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Cover Crops on the IntensiveMarket Farm
John Hendrickson, CIAS Outreach Specialist
with support fromthe Pesticide Use and Risk Reduction Projectat the Center for Integrated Agricultural Systems
University of Wisconsin-Madison College of Agricultural and Life Sciences
September, 2003
2This report is made possible by the collective effort of several public agencies:
The report is funded through a grant from the Wisconsin FarmersUnion Foundation, working with the US Environmental ProtectionAgency - Region V in Chicago as part of their Agricultural StewardshipInitiative. Based in Chippewa Falls, WFUF supports projects and programsfor all ages that foster family farming, rural life and public education onthe important role of cooperatives and agriculture in society. For moreinformation on EPA, its regional offices and their programs, go tohttp://www.epa.gov/epahome/locate2.htm
The report is a product of the University of Wisconsin – MadisonFresh Market Team serving the Pesticide Use and Risk ReductionProject (PURR). The Fresh Market Team is made up of researchers andUW Extension outreach specialists who work with fresh market growersthroughout Wisconsin. Many are associated with the UW’s Integrated PestManagement Program.
The Integrated Pest Management Program expands the use of IPMin Wisconsin crops to reduce the use of chemical pesticides, increase theuse of cultural and biological pest control tactics, improve productionefficiency and maintain the competitiveness of Wisconsin growers byproducing crops with the lowest pesticide inputs necessary. Go tohttp://ipcm.wisc.edu for more information.
PURR is the collective effort of 14 agricultural organizations that areworking together to reduce pesticide use and risk through Integrated PestManagement and other system strategies. For more information on PURRand its member organizations, go to http://www.thinkIPM.org
PURR is administered by the Center for Integrated AgriculturalSystems (CIAS), a research center for sustainable agriculture in theCollege of Agricultural and Life Sciences, University of Wisconsin –Madison. In addition to its role in facilitating the development of thisreport, CIAS provided layout and publishing services. CIAS fostersmultidisciplinary inquiry and supports a range of research, curriculum,and program development projects. It brings together university faculty,farmers, policy makers, and others to study relationships between farmingpractices, farm profitability, the environment and rural vitality. Go tohttp://www.wisc.edu/cias or call 608.262.5200 for more information.
Publication design and layout by Ruth McNair, Center for Integrated Agricultural Systems.
This report is printed on recycled paper.
1
Cover Crops on the Intensive Market FarmJohn Hendrickson, CIAS Outreach Specialist
Cover crops at work: winter-killed oats on the left and ryeon the right
IntroductionCrops that are grown solely to provide soil cover or for the purposes of increasing soilfertility are referred to as cover crops or green manures. In general, these crops areincorporated into the soil while green or just after flowering. Due their ability toprotect and enhance soils, cover crops are considered a fundamental aspect of anysustainable cropping system. The benefits of cover crops extend beyond soil health,however, as described below. In particular, more and more growers are realizing thepest management benefits of cover crops.
This publication is meant to serve as a practical guide to using cover crops in small- tomoderate-size fresh market vegetable operations—farms that may not always haveaccess to “conventional” equipment when it comes to managing cover crops. Formore complete and thorough information on cover cropping principles, see theResources section on page 11.
The Benefits of Cover CroppingCover crops bring a host of benefits to farms of all types. Due to the intensive natureand high fertility needs of fresh market produce farms, cover crops assume a vital role.As vegetable grower Dan Guenthner notes, “vegetable farms export a significantpercentage of their nutrients in the form of harvested crops each year.” By using covercrops and rotations, growers can begin to “close the nutrient loop” on their farms andrely less on purchased and imported fertilizers. The soil health benefits of cover cropsinclude:
• protection against soil erosion
• building and maintaining both active and stable organic matter
• improving soil structure and tilth
• improving the capillary action within soils (the upwardmovement of water in soils)
• increasing the biological activity in soils
• the fracturing of hardpan by deeply rooting cover crops
• the addition of nitrogen to the soil by legume cover crops (peas,clovers, vetch, etc.)
On market farms using organic and other sustainable agriculturalpractices, cover crops also can play an extremely important role inmanaging weeds, insects and diseases. One fundamental way to minimize the impact
4
2
Oats and peas are a greatcover crop combination
of pests is to ensure overall plant and crop health. By improvingsoil health and fertility, cover crops contribute to pestmanagement. However, there are more direct benefits as well.Cover crops can:
• smother or suppress weeds
• break insect and disease cycles, and provide habitat, pollen, andnectar for beneficial insects
Additional benefits of cover crops include:
• providing animal feed
• providing a source of mulch
• adding beauty to the farm
• helping balance the stress of increased production with thesatisfaction of soil building
Questions and ChallengesThe benefits of cover crops seem clear. But questions and challenges remain asvegetable growers at different scales of operation try to maximize those benefits, giventhe limitations of time and equipment. One challenge, as outlined by Dan Guenthnerat the Upper Midwest Organic Farming Conference (1), is the relationship betweensoil building and tillage. “The most commonly employed implements on most marketfarms—namely the rototiller, moldboard plow, and disc—can damage soil structure,”says Dan. “It is easy to overwork the soil, especially when growing on a small scale andrelying on a rototiller for field preparation.” In response to the situation, Dan asks,“How can green manure crops best be incorporated? Can tools and implements beredesigned to deal effectively with higher amounts of surface residue (or ‘trash’)? Canthe amount of exposed soil area in a market garden be reduced?”
Another challenge facing market growers is how to balance soil building and fertilitymanagement with the demands of succession planting and harvesting. The demands ofmaking a living on the land may not always align with the needs of the soil. Further-more, many market growers lack enough land to develop adequate cover croprotations—especially longer term rotations involving season-long cover crops.Market growers who farm near urban areas with high land prices can be pressured intopushing the land to produce as much as possible.
Finally, how can growers maximize the pest management benefits of cover crops?There is much anecdotal evidence about cover crops reducing weed, insect anddisease pressure, but far more research and experimentation is needed.
3
A small seed drill works well for plantingcover crops
The Market Farmer’s AdvantageWhile market farmers face the real challenges of time availability, lack of necessaryequipment, land availability, and economic pressures, they have some advantages aswell. Dan’s list includes:
1. Short season vegetables lend themselves perfectly to cover cropping.
2. Small fields are ideal for experimentation.
3. Cover cropping can create curiosity and open doors with neighboring“conventional” farmers.
4. Cover crops keep a garden/farm looking lush and dynamic throughout the fulllength of the growing season.
5. Cover crops help keep growers’ busy lives in balance by keeping them focused onlong-term soil building in addition to the next day’s produce delivery.
There is no shortage of creative, devoted market growers who are adept at findingnew solutions to age-old problems. The rest of this publication is devoted to sharingideas and information that will help both new and experienced growers make the bestuse of cover crops in their farming systems.
Equipment Needed to Effectively Manage Cover CropsSeeding: A simple broadcast seeder can be used on a small (garden) scale with goodsuccess. A drag, harrow, or cultipacker helps cover seeds and provides adequate seedto soil (seed to moisture) contact. Many small farms use old six-foot grain drills toplant cover crops. These can be found at auctions or used equipment dealerships for areasonable price ($100-400). With a drill, more uniform stands can be achieved thanby broadcasting. Even with a drill, a cultipacker will hasten germination.
Residue management: A flail chopper (or stalkchopper) is the implement of choice for cutting orclipping cover crops before the residue is incorpo-rated into the soil. A small (6’) used flail chopper canbe purchased for around $300 to $1,000. Theserequire a tractor with sufficient horsepower, 30 to40hp. Tractor-mounted sickle bar mowers are lessexpensive but do not chop as finely and can leave arelatively thick mat of vegetation. Without tractor-mounted implements, it is wise to clip more often soas to avoid a tall, dense stand. A good tool for clippingat a small scale is a walk behind sickle bar mower—although these can be expensive. Rotary mowers canalso be used, especially for cover crops that become
6
4
too tall or dense for a flail chopper. In a smallmarket garden, it is best to stick with low-growing,“succulent” covers such as oats, peas, and low-growing clovers. Avoid dense, matting cover cropssuch as hairy vetch that are very difficult to deal withusing small scale equipment. Appendix A on page 12includes notes on which cover crops are best suitedfor smaller scale growers.
Tillage: Cover crops are most commonlyincorporated with rototillers at smaller scales and
tractor-mounted rotovators at larger scales. Spaders (walk behind or tractormounted) can also be used. These are less damaging to soil structure than rototillers.A traditional approach would be to turn cover crops under using a moldboard plowand then follow this with a series of cultivations using some combination of a disc, fielddigger, and spike tooth harrow. Turning the cover crop under, however, places it in ananaerobic environment (lacking oxygen)—not the ideal condition fordecomposition. Inverting the soil also brings weed seeds to the surface where they cangerminate. Field diggers and power harrows are more gentle on the soil and can beused effectively. The following basic sequence, used by Dan Guenthner at CommonHarvest Farm, will incorporate most cover crops and create a nice seed bed:
1. First, flail chop the cover crop.
2. At least 24 hours later, follow with a five-foot field digger with sweeps that operateat four to six inches deep.
3. Follow with a Lely Rotera power harrow (this stirs the soil and lightlyincorporates the residue without inverting the soil).
4. Finally, use a chisel plow (that operates at 18 inches deep) to aerate the soil and layout your beds.
Between stages 3 and 4, you can elect to express some weeds and use the harrow againto create a clean seed bed.
At a small scale, rototillers or small spading tillers are about the only options (asidefrom hand digging). Because rototillers can be damaging to soil structure—especially if they are overused—it is generally best to use them at shallower depths andat lower revolutions per minute (RPMs). Another option is to find a neighboringfarmer to do primary tillage for you (with a tractor-mounted digger and/or chiselplow) before using a rototiller for final seedbed preparation.
A flail chopper works well for clipping covercrops
Regardless of the tools employed, keep themin working condition so that when the timecomes to plant, clip, or till, you can actquickly and efficiently. Timing is importantand you need to be ready to take advantageof relatively short windows of opportunityduring various seasons and betweenrainstorms. It is also important to have seedon hand and a well thought out plan. Thefollowing section provides several sequenc-ing options for planting cover crops.
Cover Cropping SequencesThere are several different windows ofopportunity for planting cover crops and a variety of cropping sequences, based onthe length of the cropping season. For example, in a field or section of a field that willbe planted to early spring crops (peas, spinach, radishes, etc.), it is best to plant acover crop the preceding fall that will winter kill, making it easy and quick to till andplant in the early spring. In an area that will be planted later with main season crops(such as tomatoes, peppers, or squash), a perennial cover such as winter rye workswell. This strategy will prevent soil erosion and keep weeds in check during the earlyspring until it is time to till and plant. There are many different options for a fullseason of over cropping. The following are sample sequences that Dan Guenthner andother market growers in the Upper Midwest have found useful and successful.
Cover crop options by season (more specific planting times are included in Appendix A)
Spring Summer FallMow fall seeded rye/vetch Rape RyeOats and peas Millets Rye and vetchNitro alfalfa with oats Sudangrass Winter rapeBerseem clover Oats and peas Peas
Buckwheat TurnipsClovers OatsFallow cycle (for weed control)
5
A field digger and spike tooth harrow can be usedto prepare the ground for seeding
8
6
Given the diversity on most fresh market vegetable farms, there are many different po-tential cover cropping sequences depending on when a cash crop is planted and howlong it remains in the ground. In addition to fitting cover crops in before and after acash crop, season-long cover cropping (full fallow season) is a highly recommendedpractice to improve soil health and to address weed, insect and disease problems.
Cover crop options by length of garden crop season1
Full Fallow SeasonSpring Summer FallRye from previous fall Buckwheat or Sudangrass Oats and peas(2-3 bu/acre) (100#/acre) (2:1 ratio)
Crop residue from previous fall Buckwheat Winter ryespring sown oats, peas, vetch (100-150#/acre)(2:2:1 ratio)
Oats and Nitro alfalfa Mow oats Winter rye
Clover or clover grass mixture Mow, plow, fallow Rye/vetchplanted previous July
Early Spring Garden(peas, radishes, lettuce, spinach, etc.)
Spring Summer FallWinter killed oats Early to mid July Winter ryeWork ground early Buckwheat or oats and peasPlant spring gardenFall plowed field Clover, oats/peas, Sudan or millet Rye/vetch
Main Season Garden(peppers, tomatoes, onions, leeks, vine crops, etc.)
Spring Summer FallRye or rye/vetch Garden planted in May/June Winter rye or oatsfrom previous fallClover or clover grass mixture Garden planted in May/June Winter rye or oats
Fall Garden(fall brassicas, carrots, lettuce, etc.)
Spring Summer FallClover or rye from previous fall or Fall garden Leave crop residuespring sown oats and peas planted July and August or seed winter rye
on crops harvestedbefore Oct. 1
1Adapted from a handout created by Dan Guenthner, Common Harvest Farm, Osceola, WI
7
Cover Cropping Sequence Notes:
• Between each cover crop and garden crop is aone- to three-week fallow cycle as a transition.This fallow cycle is an opportunity toexpress weeds. Just after weed seeds germinate, ashallow cultivation provides a stale seed bed forthe coming garden crop. Over time, these fallowperiods can be reduced as weed pressurediminishes.
• Garden crop foliage should be flail choppedquickly after harvest is complete inorder to seed an appropriate cover crop.
• Most cover crops (except buckwheat) are clipped one to three times to encouragetillering (tillers are shoots that sprout from the base of grasses). Clipping alsoprevents the cover crop from going to seed and becoming a weed in the nextgarden crop. It is also important to clip cover crops to avoid a dense stand thatmakes cutting and incorporating difficult using smaller scale equipment. This isespecially true for Sudangrass and millets.
• Buckwheat can become a weed problem if the seeds are allowed to mature. Thechallenge is to walk a fine line between providing flowers for pollinators andclipping the stand before it has set too much seed.
• Winter rye is an aggressive plant that can regrow under moderately moistconditions. It is best to clip rye before it gets too tall. If the rye exceeds 10 to 12inches before the first clipping, its regrowth potential has diminished.
• Annual rye and perennial rye are two different things. If the goal is weedsuppression, an allelopathic effect can be achieved from cereal (grain) rye.Allelopathy refers to chemicals in some plants that inhibit the germination orgrowth of other plants. Unlike cereal rye, ryegrass has no allelopathic effect.The allelopathic effect lasts four to six weeks after turning it under … well worthremembering if you plan to seed a market crop behind it.
Maximizing the Pest Management Benefits of Cover CropsResearch and experimentation on using cover crops to manage pests is increasing asboth growers and researchers recognize the potential for biological and farmingsystem approaches to address pest management challenges. Specific cover crops,cover cropping sequences, and practices have been identified that can helpaddress disease, insect and weed problems. However, some weed, insect and diseasesuppression research results have proven difficult to replicate. Someinformation about pest management benefits is purely anecdotal. The following is apartial overview of what is known about using cover crops to manage pests, butgrowers may find it challenging to get the same results in all circumstances.
Buckwheat can become a weed problem if theseeds are allowed to mature
10
8
Cover Cropping for Weed Management
Cover crops suppress weeds by competing for light and nutrients or, in some cases,releasing compounds that inhibit the germination or growth of weeds. The latter iscalled “allelopathy.” Weed suppression by cover crops varies by species, management(planting dates, planting densities, tillage, and residue management, etc.), existingweed populations and weather conditions. Particular cover crops and managementapproaches can suppress, have no effect, or even stimulate weed growth. Accordingly,shifts in weed populations can occur when using cover crops in annual rotations.Because of this, it is best to match cover crops and management to the particular weedproblems in a given situation (2).
Cereal grains and grasses are excellent choices to suppress late fall and spring weedsbecause they establish themselves quickly in cooler temperatures, cover the soil,remain in place through winter, and grow rapidly in the spring. Legumes grow tooslowly to be effective but they can be used in combination with grains and grasses toachieve both weed suppression and nitrogen fixation. To achieve the best results,
drilling is the recommended planting method (rather thanbroadcasting) because this hastens germination and resultsin a more even stand. Higher seeding rates (by as much as50%) are also recommended (2, 4).
The tillage required to incorporate winter cover cropscan bring new weed seeds to the surface, however. Somegrowers are experimenting with leaving cover crop resi-dues on the surface as mulch, but this can create obviouschallenges with direct seeded crops (particularly thosethat require a fine seed bed) as well as transplanting.Summer weeds can be smothered with warm seasonannual cover crops such as buckwheat or Sudangrass, orby season-long cover crops.
As mentioned above, some cover crops have an allelopathic effect, cereal rye being themost notable. Rye and rye/vetch combinations are common winter covers that aretilled before transplanting or seeding large seeded crops such as beans. Anotherapproach is to bale the rye and then use it for mulch. In addition to rye, oats andbarley can inhibit germination and root growth (4). Simply incorporating largeamounts of residue, especially if succulent, often causes a sharp increase in soil-bornepathogen populations, especially damping-off fungi, which attack seeds as theygerminate. This may account for some of the reduced weed and crop germinationobserved shortly after killing and/or incorporating cover crops (2). Because of thiseffect, it is wise to wait three weeks or so after incorporation before plantingdirect-seeded crops.
Clover interseeded in corn helps keepdown weeds
9
A swath of spring-sown oats and peas next to arecently plowed bed
Many new vegetable growers face enormous weedpressure as they convert old hay fields, pastures, andlawns into vegetable gardens. Appendix B on page 16contains several cover cropping scenarios to ease thistransition.
Cover Cropping for Insect Management
Cover crops can affect a farm’s insect community inseveral ways. They can attract both insect pests andbeneficials by providing shelter and food as well asmaking cash crops more difficult to locate. Manage-ment is complicated given that cover crops can act as a source and/or a sink forbeneficial and pest insects (3). Given this complexity, careful observation, planningand timing are important.
The simplest strategy to achieve insect management benefits is to provide a diversearray of vegetation (3). Diversity in plant species and habitats contributes to overallfarm diversity and helps ensure a balanced insect community, including beneficialpredators. Increasing diversity can be achieved by:
• selecting a diversity of cash crops
• utilizing a diversity of cover crops (such as planting both buckwheat andSudangrass as summer cover crops since each has unique insect associations)
• establishing permanent or semi-permanent hedgerows
• planning cover crop plantings and mowings to ensure that something is always inbloom (such as waiting until buckwheat has flowered before plowing a rye/vetchcombination or mowing/plowing only portions of a stand at a time)
• strip cropping (the practice of growing crops in strips between adjacent stands ofcover crops)
Strip cropping can be a particularly useful strategy because it provides beneficialhabitat close to cash crops. For example, a solid stand of rye/vetch or clover can bemowed and plowed in strips, leaving habitat for ladybugs and other predators. The listof cover crops in Appendix A includes notes on whether various cover crops aresuitable for strip cropping.
Planting special hedgerows to attract beneficial insects is another approach. Someseed companies (such as Johnny’s Selected Seeds) offer packets that can be used tocreate borders or strips of beneficial habitat. Some growers have created morepermanent hedgerows that not only attract and harbor beneficials, but also yield a
12 marketable crop such as curly willow or various types of perennial flowers and herbs.For example, members of the Umbelliferae family (such as caraway, dill and fennel) areattractive to parasitic wasps. Flowers in the Compositae family (sunflowers, asters,goldenrod, daisy, cone flower, etc.) attract insects such as ladybugs, pirate bugs, andspined soldier bugs, can be maintained in permanent beds, and are readily marketedas cut flowers (3).
The following table, published by Plotkin, list insects (both pest and beneficial)attracted to common cover crop species.
In addition to above-ground interactions, plants can impact soil-dwelling species.Oats, barley, and sorghum-Sudangrass have been shown to reduce root-knotnematodes—a pest that can reduce carrot quality and affect other vegetable cropssuch as onions and potatoes. Research on various sorghum-Sudangrass hybrids andcultivars reveals that the leaves of these plants produce a nematicidal compound. Totake advantage of this, sorghum-Sudangrass must be mowed and well-incorporatedbefore first frost and while still green (4).
Other species may actually increase detrimental species. Vetchcan cause increases in root-knot nematodes as well as thesoybean cyst nematode.
Cover Cropping for Disease Management
Cover crops can help reduce disease problems in vegetables invarious ways. Most obviously, cover crop rotations breakdisease cycles in the soil. Other benefits can come from stripcropping or utilizing cover crops as mulches. Mulches candelay the onset of early blight in tomatoes by reducing soil
Insects attracted to common cover crop species
Cover crop Beneficial insects Pest insectsBuckwheat Parasitic wasps, ladybugs Tarnished plant bugs and
tachinid and hover flies, aphids (note: aphids can actlacewings as a food source for
beneficials)Clovers Parasitic wasps, big eyed Spider mites & flower thrips
bugs, minute pirate burgs, (note: flower thrips can preyladybugs, tachinid flies, and on spider mites and provideaphid midges food for several predatory
insects)Hairy vetch Minute pirate bugs, ladybugs Tarnished plant bugs
predatory and parasitic waspsCereals Ladybugs Aphids
Peas grow in a new seedbed where covercrops have been incorporated
splash onto leaves. Preliminary research suggests that oats may help reduce vegetablecrop diseases caused by Rhizoctonia (4). Because some cover crop species are relatedto cash crops (most notably field peas), it is wise to rotate cover crops. Pea diseasessuch as Sclerotinia can build up quickly if peas are planted in successive years in thesame location (4).
Seed sourcesSome cover crop seed, such as oats and rye, can be bought from neighboring farmers.Other types, such as oats and peas, clovers, and sorghum-Sudangrass, are readilyavailable at a local co-op elevator or feedstore. More specialized seed, such as hairyvetch, rape, ryegrass, berseem clover, annual alfalfa, and millet, is available fromvarious seed companies. Upper Midwest sources include:
• Premium Seed Co., Shakopee MN, 800-752-0407
• Albert Lea Seed House, Albert Lea, MN, 800-352-5247
• L.L. Olds Seed Co. Madison, WI, 800-356-7333
Citations1. Dan Guenthner, Common Harvest Farm, 212 280th St. Osceola WI 54020;
715-294-2831. Dan has given several presentations on cover crops at the UpperMidwest Organic Farming Conference. An earlier version of this publication wasco-authored by Dan and this paper borrows extensively from his workshophandouts.
2. Cover Crop Weed Suppression in Annual Rotations, Edward Peachy et al., Oregon StateUniversity Extension Service, 1999. www.eesc.orst.edu
3. Using Cover Crops and Green Manures to Attract Beneficial Insects, Jeremy Plotkin,University of Connecticut Integrated Pest Management Program.www.hort.uconn.edu/ipm
4. Managing Cover Crops Profitably, Sustainable Agriculture Network, 1998.www.sare.org
Other Recommended Resources• Anne and Eric Nordell; Rd. 1, Box 205, Trout Run, PA 17771; (717) 634-3197.
52-minute video and booklet on cover cropping and soil building, $10.
• Appropriate Technology Transfer to Rural Areas (ATTRA). Call and ask for freeinformation about cover crops and green manures. 1-800-346-9140.www.attra.org
• Green Manuring: Principles and Practice, 1989, Woods End Agricultural Institute.
• Green Manuring: Principles and Practice, 1927 (out of print and hard to find but worththe search).
11
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gro
wth
. M
ow h
igh;
it is
into
lera
nt o
f low
mow
ing.
Plo
w
unde
r in
fall
if an
ear
ly v
eget
able
cro
p w
ill fo
llow
in
sprin
g. If
ove
rwin
terin
g, p
low
bef
ore
flow
erin
g; d
o no
t allo
w to
set
see
d. M
atur
e sw
eetc
love
r is
fibro
us a
nd b
reak
s do
wn
slow
ly. E
xcel
lent
cho
ice
for i
nter
crop
ping
if p
lant
ed b
efor
e th
e ve
g. c
rop
or
1-ye
ar s
oil b
uild
ing
crop
. Mix
with
oat
s fo
r add
ed
biom
ass.
Che
ap a
nd e
asy
to p
lant
.
No,
requ
ires
plow
ing
to
inco
rpor
ate.
Ber
seem
C
love
rE
xtre
mel
y vig
orou
s, ta
ll an
nual
whi
te c
love
r. To
lera
nt o
f wet
con
ditio
ns.
Exc
elle
nt n
itrog
en fi
xer.
Use
alfa
lfa/c
love
r ino
cula
nt.
Spr
ing
or
late
sum
mer
(if
moi
stur
e is
ade
quat
e)
1/2
to 2
15 to
25
Bes
t if d
rille
d bu
t can
be
harro
wed
in. M
akes
ex
celle
nt h
ay o
r hea
vy q
uant
ities
of m
ulch
. Cut
w
hen
7-20
inch
es. D
on't
mow
clo
se; l
eave
1-3
in
ches
of s
tubb
le. B
erse
em le
aves
a fr
iabl
e se
edbe
d so
spr
ing
tilla
ge re
quire
men
ts a
re
min
imal
. Tra
nspl
ant d
irect
ly in
to b
eds.
Exc
elle
nt
wee
d su
ppre
sor.
Goo
d fo
r int
erpl
antin
g be
caus
e of
slo
wer
sum
mer
gro
wth
. Mix
with
oat
s fo
r bi
omas
s or
1-s
easo
n so
il bu
ildin
g.
Yes
. Can
be
cont
rolle
d by
m
owin
g an
d no
he
avy
tilla
ge is
ne
eded
.
See
ding
rate
:
* Ada
pted
from
info
rmat
ion
publ
ishe
d by
Cha
rles
Mar
r, R
hond
a Ja
nke
and
Paul
Con
way
in "
Cov
er C
rops
for V
eget
able
s G
row
ers"
Kan
sas
Stat
e U
nive
rsity
, 199
8.
13
Pla
ntin
gSu
itabl
e fo
r Cr
opCh
arac
teris
tics
Tim
e#/
1000
ft2
#/ac
reM
anag
emen
t and
Com
men
tssm
all s
cale
?S
oybe
anU
prig
ht b
ushy
legu
me.
M
ust b
e pl
ante
d in
war
m
soil.
Stro
ng N
fixe
r. G
row
on
mos
t soi
ls. U
se
soyb
ean
inoc
ulan
t.
Late
May
th
roug
h ea
rly
Aug
ust
2 to
450
to 1
50D
rill o
r har
row
in. E
xcel
lent
for p
lant
ing
afte
r an
early
veg
etab
les;
mow
ed re
sidu
e le
aves
fria
ble
seed
bed
next
spr
ing.
Ear
ly p
lant
ings
bes
t in
corp
orat
ed b
y S
ept.
to m
axim
ize
bene
fits.
If
field
is n
ew o
r wee
dy p
lant
a fa
st-g
row
ing
cove
r cr
op fi
rst (
buck
whe
at).
Let b
eans
gro
w 8
0-10
0 da
ys to
max
imiz
e bi
omas
s. C
an b
e pl
owed
, di
sked
or m
owed
(lea
ving
resi
due
on th
e su
rface
). C
ost,
avai
labi
lity,
rapi
d gr
owth
and
N fi
mak
e it
an e
xcel
lent
cho
ice.
Yes
.
Fiel
d P
eas
Gro
w li
ke g
arde
n pe
as o
nly
talle
r. V
ery
cold
tole
rant
an
d go
od N
fixe
rs (m
ost N
fix
ed b
efor
e flo
wer
ing)
. Use
pe
a/ve
tch
inoc
ulan
t.
Spr
ing
2 to
850
to 2
00D
rill o
r bro
adca
st a
nd h
arro
w. F
or m
ax. b
iom
ass,
N
, and
wee
d su
pres
sion
, see
d he
avily
. Mow
and
di
sk to
inco
rpor
ate.
Hea
vy s
tand
s w
ill c
log
sick
le
bar m
ower
s. P
rodu
ces
so m
uch
biom
ass
that
sm
all s
eede
d cr
ops
cann
ot b
e so
wn
imm
ed.
follo
win
g. P
eas
mix
wel
l with
oat
s or
bar
ley.
Pea
, oa
t, an
d ha
riry
vetc
h m
ixtu
res
are
exce
llent
for
soil
build
ing
and
avai
labl
e fro
m s
ome
supp
liers
. B
est u
se is
on
grou
nd to
be
plan
ted
in J
une/
July
.
Yes
, mow
to
cont
rol p
eas.
Ti
lling
is e
asie
r if
vines
rot 1
-2
wee
ks o
r are
re
mov
ed a
nd
used
as
mul
ch.
Ann
ual
Whi
te
Clo
ver
Sim
ilar t
o ye
llow
-blo
ssom
sw
eetc
love
r. D
eep
tapr
oote
d an
d a
stro
ng N
fix
er. U
se a
lfalfa
/clo
ver
inoc
ulan
t.
Spr
ing
or
early
fall
1 to
215
to 3
0D
rill o
r bro
adca
st a
nd h
arro
w. G
row
s ra
pidl
y an
d ca
n be
com
e w
oody
whe
n m
atur
e an
d di
fficu
lt to
in
corp
orat
e. M
ow a
s ne
eded
. Mix
with
oat
s fo
r a
nurs
e cr
op. L
ater
pla
ntin
gs m
ake
good
gro
wth
be
fore
bei
ng w
inte
rkill
ed. S
eed
is h
ard
to fi
nd
(mos
t com
mon
var
iety
is H
ubam
). A
s m
ost
clov
ers
are
bien
nial
, mak
e su
re w
hat y
ou a
re
getti
ng is
ann
ual s
wee
tclo
ver.
Yes
.
Oat
sFa
st g
row
ing
and
frost
to
lera
nt a
nnua
l. E
xten
sive
, fib
rous
root
s ho
ld s
oil a
nd
prod
uce
biom
ass.
Tol
eran
t of
wet
soi
ls a
nd lo
w p
H. I
f al
low
ed to
mat
ure,
oat
s w
ill
rese
ed a
nd n
ew g
row
th w
ill
win
terk
ill.
Late
win
ter
(fros
t se
edin
g)
and
sprin
g or
fall
2 to
410
0 to
14
0 (1
-2
bush
els)
if
mix
ed;
up to
4
bush
els
if se
eded
al
one.
"Fee
d" o
r "se
ed"
oats
are
acc
epta
ble
for c
over
cr
op u
se. D
rill o
r bro
adca
st a
nd h
arro
w. T
o pr
oduc
e m
ulch
, mow
whe
n ne
eded
. Oat
stra
w
deco
mpo
ses
rapi
dly
and
acts
like
leaf
mul
ch in
th
e fo
rest
. Oat
s ar
e a
good
trap
cro
p; la
te
sum
mer
pla
ntin
gs w
ill h
old
N fr
om m
anur
e ap
plic
atio
ns. O
ats
prov
ide
good
win
ter e
rosi
on
cont
rol.
Oat
s ar
e ex
celle
nt fo
r mix
ing
with
le
gum
es. V
ersa
tile,
ava
ilabl
e an
d ch
eap.
Yes
.
See
ding
rate
:
16
14
Plan
ting
Suita
ble
for
Crop
Char
acte
ristic
sTi
me
#/10
00ft
2#/
acre
Man
agem
ent a
nd C
omm
ents
smal
l sca
le?
Buc
k-w
heat
Fast
-gro
win
g, w
arm
se
ason
ann
ual (
mat
ures
in
40-5
0 da
ys).
Not
dro
ught
or
frost
tole
rant
.
Late
spr
ing
to la
te
sum
mer
2 to
350
to 1
00D
rill o
r bro
adca
st a
nd h
arro
w. F
ast g
row
th
enab
les
buck
whe
at to
sm
othe
r wee
ds a
nd fo
r se
vera
l seq
uent
ial p
lant
ings
to b
e m
ade
in o
ne
seas
on. O
nce
mow
ed, r
esid
ue d
ecom
pose
s ra
pidl
y an
d so
il is
fria
ble;
littl
e til
age
is n
eces
sary
fo
r nex
t cro
p. W
ill re
seed
itse
lf an
d ca
n be
com
e a
wee
d if
flow
ers
mat
ure
to s
eed.
Buc
kwhe
at
resi
due
can
be a
goo
d w
inte
r cov
er if
late
pl
antin
gs a
re th
ick
and
grow
th is
ade
quat
e.
Yes
. Exc
elle
nt
choi
ce to
follo
w
early
ve
geta
bles
or
to h
elp
clea
n up
a w
eedy
fie
ld.
Japa
nese
M
illet
Fast
gro
win
g su
mm
er
annu
al g
rass
. Lim
ited
frost
to
lera
nce
and
will
win
terk
ill.
Req
uire
s fe
rtile
soi
l for
ra
pid
grow
th. T
oler
ates
fre
quen
t clip
ping
s an
d m
akes
exc
elle
nt
fora
ge/h
ay. T
oler
ant o
f bot
h dr
ough
ty a
nd w
et s
oils
.
Late
spr
ing
thro
ugh
Aug
ust
1 to
1-
1/2
25 to
30
Dril
l or b
road
cast
and
till
shal
low
. Man
ure
or
ferti
lize
for b
est r
esul
ts. W
hen
inte
nded
as
sum
mer
long
trap
cro
p, m
owin
g is
impo
rtant
. Clip
be
fore
hea
ding
out
(~60
day
s) a
nd le
ave
3" o
f st
ubbl
e. N
ot s
uita
ble
for m
ixin
g bu
t a g
ood
choi
ce
for a
full
seas
on s
mot
her c
rop
follo
win
g ea
rly
vege
tabl
es. G
ood
choi
ce fo
r cle
anin
g w
eedy
fie
lds
or c
onve
rting
land
to v
eget
able
pro
duct
ion.
A
lso
exce
llent
if th
ere
is a
nee
d fo
r mul
ch o
r fee
d.
Yes
, but
mak
e su
re s
oil i
s fe
rtile
eno
ugh
to s
uppo
rt m
ultip
le
cutti
ngs.
Sor
ghum
-S
udan
- gr
ass
Fast
gro
win
g, d
roug
ht
tole
rant
ann
ual g
rass
. Will
gr
ow o
ver 6
' if l
eft u
ncut
. G
row
s on
mos
t soi
ls b
ut
need
s fe
rtile
soi
ls fo
r bes
t re
sults
. Win
terk
ills.
Late
spr
ing
thro
ugh
July
1 to
215
to 4
0D
rill o
r bro
adca
st a
nd h
arro
w. A
goo
d N
trap
cro
p an
d ex
celle
nt s
mot
her c
rop
that
pro
duce
s tre
men
dous
bio
mas
s (m
ore
than
any
oth
er c
over
cr
op) e
ven
with
mow
ing.
Dec
ompo
ses
slow
ly;
allo
w 1
mon
th b
efor
e pl
antin
g ne
xt c
rop.
Nee
ds
plen
tiful
man
ure
to re
ach
full
pote
ntia
l. If
left
too
long
it c
an b
ecom
e un
man
agab
le.
No,
too
rank
in
grow
th h
abit.
E
ven
larg
e-
scal
e fa
rmer
s ne
ed h
eavy
du
ty m
ower
s to
cu
t for
hay
or
sila
ge.
Fora
ge
bras
sica
s (c
abba
ge
fam
ily
crop
s)
Mos
t com
mon
type
s ar
e tu
rnip
s, ra
pe a
nd k
ale.
Use
re
adily
ava
ilabl
e ch
eap
varie
ties
such
as
Pur
ple
Top
Turn
ips.
Will
tole
rate
lo
w fe
rtilit
y bu
t do
best
un
der f
ertil
e co
ndiit
ons.
R
ape'
s lo
ng ta
p ro
ot
loos
ens
heav
y so
ils.
Spr
ing,
su
mm
er o
r fa
ll
1/4
for
turn
ips
1/3
for
rape
or
kale
5 to
7 fo
r tu
rnip
s 8
to 1
5 fo
r ra
pe o
r ka
le
Dril
l or b
road
cast
with
ligh
t inc
orpo
ratio
n. N
ot
reco
mm
ende
d if
vege
tabl
e br
assi
cas
are
grow
n ne
arby
. Will
tole
rate
mow
ing
or g
razi
ng.
Will
trap
N
and
oth
er n
utrie
nts
and
prov
ides
gro
und
cove
r af
ter w
inte
rkill
. Val
ue a
s a
cove
r cro
p is
lim
ited
unle
ss li
vest
ock
fora
ge is
nee
ded.
Bes
t use
d fo
llow
ing
early
veg
etab
les,
mix
ed w
ith s
umm
er
legu
mes
, or i
n m
ixes
with
pea
s, o
ats,
vet
ch, e
tc.
Can
als
o be
use
d un
der s
wee
t cor
n.
Doe
sn't
requ
ire
heav
y eq
uipm
ent b
ut
valu
e is
lim
ited
unle
ss
lives
tock
fora
ge
is n
eede
d.
See
ding
rate
:
15
Plan
ting
Suita
ble
for
Crop
Char
acte
ristic
sTi
me
#/10
00ft
2#/
acre
Man
agem
ent a
nd C
omm
ents
smal
l sca
le?
Hai
ry
Vet
chC
old
tole
rant
vin
ey le
gum
e.
Exc
elle
nt N
fixe
r (10
0 lb
s/ac
re).
Nee
ds p
H o
f 6 o
r 7
for b
est r
esul
ts. T
oler
ates
m
ost s
oils
but
will
not
su
rvive
floo
ding
. Dro
ught
to
lera
nt o
nce
esta
blis
hed.
To
lera
nt o
f mow
ing
but
into
lera
nt o
f sha
de. U
se
pea/
vetc
h in
ocul
ant.
Spr
ing,
S
umm
er o
r Fa
ll (s
umm
er
plan
tings
ge
nera
lly
less
su
cess
ful)
1 to
225
to 5
0B
est i
f dril
led
but c
an b
e ha
rrow
ed in
. Sow
with
a
nurs
e cr
op o
f sm
all g
rain
in 1
:1 o
r 1:2
ratio
by
volu
me
(vet
ch to
sm
all g
rain
). Fo
r ove
rwin
terin
g,
plan
t 3-4
wee
ks b
efor
e a
hard
fros
t. A
wet
spr
ing
can
dela
y in
corp
orat
ion
and
a m
atur
e sm
all g
rain
m
ay h
inde
r bre
akdo
wn
of th
e ve
tch
follo
win
g in
corp
orat
ion.
Mow
vet
ch/s
mal
l gra
in m
ixtu
res
if in
corp
orat
ion
is d
elay
ed. I
ncor
pora
te in
Apr
il fo
r a
May
-pla
nted
cas
h cr
op. P
low
to in
corp
orat
e or
us
e he
avy
disk
and
chi
sel p
low
. Spr
ing-
sow
n ve
tch
is e
asie
r to
man
age
and
can
be le
ft st
andi
ng, t
illed
und
er o
r dis
ked
in th
e fa
ll.
In g
ener
al, n
o.
It ca
n be
m
owed
unt
il it
dies
, but
oth
er
crop
s ar
e ea
sier
to
man
age.
Vin
ey
grow
th w
ill
quic
kly
clog
a
roto
tille
r.
Oth
er
Vet
ches
Less
win
ter h
ardy
than
H
airy
. All
requ
ire p
ea/v
etch
in
ocul
ant.
Sam
e as
H
airy
Sam
e as
H
airy
Sam
e as
H
airy
Sim
ilar t
o H
airy
but
not
as
exac
ting.
See
d pr
ices
ar
e hi
gher
.Y
es.
Gra
in R
ye
(win
ter
rye)
Ver
y ha
rdy
smal
l gra
in.
Gro
ws
long
er in
fall
than
ot
her g
rain
s an
d re
sum
es
grow
th e
arlie
r in
sprin
g.
Gro
ws
on m
ost s
oils
. E
xtre
mel
y ef
ficie
nt n
utrie
nt
scav
enge
r mak
ing
it an
ex
celle
nt N
trap
cro
p.
Den
se, f
ibro
us ro
ots
help
bu
ild o
rgan
ic m
atte
r and
m
ake
soil
mor
e fri
able
.
Late
su
mm
er to
fa
ll. C
an b
e sp
ring
plan
ted
but
will
die
be
fore
flo
wer
ing
and
chea
per
optio
ns
exis
t.
2 to
550
if
mix
ed
with
le
gum
e.
60-2
00 if
se
eded
al
one
Can
be
broa
dcas
t and
tille
d bu
t bes
t if d
rille
d.
Can
ger
min
ate
on th
e su
rface
if m
oist
ure
is
adeq
uate
. In
Spr
ing,
till
whe
n ry
e is
6-8
" or
wai
t un
til it
flow
ers.
Can
be
used
as
win
dbre
ak b
y le
avin
g st
rips
betw
een
beds
. Ofte
n so
wn
with
H
airy
vet
ch b
ut th
is m
ixtu
re c
an g
et a
way
from
yo
u un
less
soi
l is
sand
y or
ver
y w
ell d
rain
ed. R
ye
show
s w
eed
supp
ress
ing
(alle
lopa
thic
) abi
litie
s (in
clud
e ry
e st
raw
) and
is u
sefu
l to
help
cle
an
wee
dy a
reas
. Tre
men
dous
bio
mas
s pr
oduc
tion
can
crea
te c
halle
nges
for i
ncor
pora
tion
and
prob
lem
s w
ith p
lant
ing
and
germ
inat
ing
smal
l se
eded
veg
etab
les.
Mai
n ch
alle
nge
is h
avin
g tim
e fo
r ade
quat
e in
corp
orat
ion
betw
een
sprin
g ra
ins.
It ca
n be
m
anag
ed
with
out p
low
s or
hea
vy d
isks
if
inco
rpor
ated
ea
rly e
noug
h.
Or l
et fl
ower
, m
ow, a
llow
to
deco
mpo
se,
and
plan
t su
mm
er
legu
me
or fa
ll ca
sh c
rop.
Ann
ual
Rye
gras
sFa
st g
row
ing
cool
sea
son
gras
s. T
oler
ates
mos
t so
ils, i
nclu
ding
wet
. Den
se
root
sys
tem
is e
xcel
lent
for
trapp
ing
N, h
oldi
ng s
oil a
nd
loos
enin
g he
avy
soils
. G
row
th h
abit
com
plim
ents
cl
over
s. N
ot d
roug
ht
tole
rant
. Will
sel
f see
d.
Spr
ing
or
late
sum
mer
to
ear
ly fa
ll
1 to
218
to 4
0B
est d
rille
d bu
t can
be
tille
d in
sha
llow
ly. E
asy
to
esta
blis
h an
d gr
ows
rapi
dly.
Mow
ing
is n
ot
nece
ssar
y ex
cept
to a
void
set
ting
seed
. Unl
ike
othe
r mat
ure
smal
l gra
ins,
ann
ual r
yegr
ass
stay
s gr
een
and
is e
asie
r to
inco
rpor
ate,
alth
ough
the
dens
e ro
ot s
yste
m c
an ta
ke ti
me
to d
ecom
pose
(s
mal
l see
ded
vege
tabl
es a
re n
ot re
com
men
ded
follo
win
g ry
egra
ss).
Exc
elle
nt c
hoic
e as
a n
urse
cr
op w
ith le
gum
es o
r for
pat
hway
s.
Yes
, eas
ily
inco
rpor
ated
if
tille
d ea
rly in
S
prin
g.
See
ding
rate
:
18 Appendix B: Bringing Land into Production and TacklingPersistent Weeds *
Getting off to a good start is important in any new enterprise. In organic vegetableproduction, decisions made early in your planning process can have significantinfluence on the success of the farm for years to come. Rather than delve into thequestion of how to find land suitable for vegetable farming, this handout assumes youalready have a site selected.
The first question to answer is: Has the land been in crop production in thepreceding year? If a row crop (corn or beans) or a small grain has been grown in theprevious season, the tillage necessary to convert the land to vegetables will beconsiderably less than if you are following extensively rooted crops such as alfalfa,pasture, or grass hay ground.
In Dan Guenthner’s experience—after relocating his farm operation five times—it isdifficult to find certifiable organic ground that has been recently cultivated. As aresult, many market growers are forced to follow a deeply rooted sod. It is also likelythat this sod will contain Quackgrass and other rhizomes with well-established rootstructures. These grasses are difficult to control using organic methods. However, inthe process of preparing your ground for intensive vegetable production, these samegrasses can teach you about your soil structure, weed pressure, and how water movesover and through your soil.
Here are some general guidelines for bringing fallow ground into production:
1. Start early. Plan on starting this process a full season before you intend to gardenon this land. Dan likes to bring new land into production in July or August of thepreceding year. This allows time to cultivate the ground a number of times so that hecan dry up the rhizomes in the sod. By starting this process in mid-summer, he alsoavoids having too much exposed ground during the traditionally rainy months of Mayand June. In most cases he then follows this four- to six-week cultivating process witha fall-seeded cover crop of winter hardy rye. The fast-growing rye assists in breakingup the remaining residue.
2. Be careful not to overwork the ground. A heavily matted sod may require theuse of a moldboard plow. If you do not own one, consider hiring a neighboringfarmer to plow your field or garden for you. If you do plow, do so only to the depthof the root zone of the sod. In this process the plow is used as an under cutter. Theresulting action will turn the sod up to dry rather than burying it deep where it may
16
not fully decay and may create a sponge-like mat that disrupts the capillarity of the soil.Many gardeners use rototillers to dice up this heavy sod structure. In doing so, theycan spread the rhizomes rather than keeping them intact and effectively dry them up.Dan’s main tillage tools include a 5-shank field cultivator with 16” sweeps. This toolundercuts the residue at a depth of four to six inches. He then follows with a LelyRoterra (power harrow) that stirs the soil and knocks off the roots of the sod residue.
3. Fall apply nutrients. By starting early to bring land into production, you willhave an opportunity to learn about your soil. Dan likes to begin with a croppinghistory going back as far as possible. He may choose to have a soil test conducted, butif a leguminous sod precedes the crop he may not. Correcting the pH level, ifnecessary, is important. Dan typically fall applies turkey manure at a rate between 5and 8 tons/acre. He then covers the ground with a fall cover crop. But he oftenleaves a small area fallow. This allows him to plant garlic the first fall as well as havesome ground bare for the earliest spring crops.
“I cannot underscore enough the importance of starting early with this process,” saysDan. One of the most important reasons for this is to gain a better understanding ofthe variety and amount of weeds to anticipate your first season. This window oftime allows you an opportunity to express weeds and identify areas of you field thatmay be better suited for specific crops. Carrots and onions in particular benefittremendously from being planted in areas with less weed pressure.
Dan also likes to use the late fall and early winter to pace off a new field and mark rowlengths and room necessary for headlands and roadways. Getting to know the texture,slope and general qualities of your soil a full season ahead will pay immediatedividends to you.
Tackling Persistent Weeds
Even after a year of cover cropping, troublesome weeds may remain. Dealing withgrassy areas—and Quackgrass in particular—can be a challenge but there arecover-cropping methods that can greatly reduce if not eliminate these weeds. Hereare several approaches that have worked for other growers:
• Buckwheat – Buckwheat – Rye.1 This method will sacrifice growing amarketable crop but can be very effective. It also contributes nutrients and improvessoil structure and tilth. Till the area in the spring as soon as the area is dry enough. Ifthe area is small, you can walk over the area and remove exposed rhizomes and roots.When the weather turns warm and all danger of frost is past, plant the first crop ofbuckwheat. It will likely be necessary to till again immediately before planting toeliminate grassy regrowth and early spring weeds that may have sprouted. Seed the
17
20 buckwheat heavily (60-90 pounds per acre or 3 pounds per 1,000 square feet). Thebuckwheat must form a dense canopy in order to be effective. Till the buckwheatwhen it just begins to flower to prevent it from setting seed. Allow weeds togerminate and then till the area again and reseed buckwheat at the same heavy rate.This second crop should be tilled under in late summer or early fall, at least 3 weeksbefore first frost.
Let the area rest for one week before seeding winter rye at a rate of 90-120 poundsper acre or 3 pounds per 1,000 square feet. It will germinate and grow a few inchesbefore going dormant for the winter. In early spring, the rye will green up with newgrowth. Till in the rye at least two weeks before planting vegetable crops. In any case,do not let the rye grow much beyond 12 inches as it will become very difficult to tilldown with small-scale equipment.
• Winter cover – Fallow – Winter cover.2 Anne and Eric Nordell in Pennsylvaniagrow back-to-back winter cover crops to manage weeds. A brief stint of aggressivesummer tillage between the two cover crops keeps annual weeds from setting seed.First, yellow blossom sweetclover is overseeded at 20 to 24 lb./acre into early cropssuch as onions or spring lettuce. Lettuce is overseeded a week or two after plantingbut before leaves open up to trap sweet clover seeds, while onions are overseedednear harvest. The Nordells walk up and down every other row with a hand-crankbroadcast seeder. They harvest the cash crop, then let the clover grow throughsummer. Yellow blossom sweetclover (one of the best cover crop choices for warm-season nitrogen production) puts down a deep taproot before winter if seeded in Juneor July, observes Eric. Note: the clover alone will not suppress weeds. It works ontheir farm because of their successful management efforts over a decade to suppressoverall weed pressure by crop rotation and varied cover crops.
The following spring, the sweetclover grows until it is about knee-high in mid-May.Then the Nordells clip it just before it buds. They let the regrowth bloom to attractpollinators and beneficial insects to the field, before clipping it again in July. Inearly- to mid-July, the Nordells moldboard plow the sweetclover to kill it. They thenleave the ground in bare fallow, working it with a spring tooth harrow to hit perennialweeds at the weakest point of their life cycle. Harrowing every two to three weeksbrings weed roots and rhizomes to the soil surface, where they bake in the summersun. The harrowing also kills flushes of annual weeds before they can set seed. Afterfive years in this weed-killing rotation, the Nordells have been able to cut back onharrowing. In mid-August, the Nordells plant a second, overwintering cover crop. Inthis rotation, they seed a mix of rye and hairy vetch. They broadcast and lightlyincorporate about 80 pounds rye and 30 pounds vetch per acre. The rye establishesquickly, putting on good growth both above and below the surface, while the vetchfixes nitrogen. Another combination is yellow, red and white clover in a 2:2:1 ratio by
18
volume. Rye and vetch are a popular combination to manage nitrogen. The rye takesup excess N from the soil, preventing leaching. The vetch fixes additional nitrogenwhich it releases after it is killed the following spring prior to planting the next cashcrop. With the August seeding, the Nordells’ rye/vetch mixture produces most of itsbiomass in fall. The Nordells plow the rye/vetch mix after it greens up in late Marchto early April, working shallowly so as not to turn up as many weed seeds. They foregomaximum biomass and N for earlier planting of their cash crop—tomatoes, peppers,summer broccoli or leeks—around the end of May.
• Spring fallow – Pumpkins – Fall/winter cover. This method allows amarketable crop to be grown. First, allow weeds/Quackgrass to grow in the springuntil six- to eight-inches tall. At this point the Quackgrass begins transferring energyresources away from its roots and into producing a seed stalk and head. While it isvulnerable, moldboard plow and disk the area lightly. A series of cultivations with aspring tine harrow (field digger) will knock back regrowth, bring rhizomes up to thesurface to dry out, and can also drag rhizomes to the edge of the field. Pumpkins arethen transplanted into the field. Cultivate again as necessary before the pumpkinsbegin to vine. The pumpkin vines will quickly form a closed canopy and suppressweed growth. You may want to consider a closer spacing than normal (four to five feetbetween rows rather than six feet) to be assured of a quick-forming, dense canopy. Asthe pumpkin vines die back in the fall, a late fall cover crop (oats and peas, rye, or ryeand vetch) can be overseeded. This method requires a sufficiently long growing seasonto achieve a decent pumpkin harvest (the transplants may not go into the field as earlygiven the series of cultivations prior to planting) but it has been used successfully insouthern Wisconsin.
Mulching
Another non-chemical means of removing weeds is mulching heavily for a year. Note:this method is more feasible and appropriate on smaller scale gardens. First, apply athink layer of organic mulch (hay, leaves, even fresh manure ... but only if the areawon’t be producing crops for a year). Then top this with some kind of material thatwill block out light (black plastic, layered newspaper, or old tin roofing). Leave thison for one full year. An exception is plastic. This should be removed before winter orelse it will begin to break apart. After the spring thaw, remove the covering and pullback the mulch. Check to see if any roots or rhizomes survived their year of darkness.The soil should be ready for planting, but if not, cover the garden plot back up foranother year.
Plan only a fall garden
If you are unable to cultivate the ground during the preceding season, a garden is stillpossible, albeit more difficult. One consideration would be to not push for a spring
19
22crop. Rather, give yourself time to get the land adequately ready and plan for asummer or, better yet, a fall garden. On a small scale almost anything is possible. Onecan plant into spring-plowed sod within three weeks. However, yields are usuallycompromised and weed pressure can be significant.
Don’t be afraid to ask neighboring farmers for advice. Many will offer it whether youask for it or not! Remember to start small, be realistic, and enjoy the work.Good luck!
* Prepared by John Hendrickson, Center for Integrated Agricultural Systems,UW-Madison and Dan Guenthner, Common Harvest Farm. 2002
1 Adapted from Weed Ending Secrets, Rodale Press Inc., Emmaus, PA, 1994.
2 Adapted from Managing Cover Crops Profitably, Second Edition, by the Sustainable Agriculture Network, reprinted 2000, SAN, Beltsville, MD, pp. 34-42. Complete text: www.sare.org/handbook/mccp2/index.htm
To order: http://www.sare.org/htdocs/pubs/ToOrder.html
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