Winter Season Produce

Remembering What We Once Knew

Phil Hannay, Kathy Kubal and Ashley Rickards

Trumpeter Swan Farm, Buffalo, MN

phil_hannay@kaphian.com

Advantages for Minnesota Growers

• Decent Soils• Ample Moisture• Harsh Winter Reduces Pest Problems• Sunny Weather Reduces Mold Problems• Long Warm Summer Days Hasten Growth• Excessive Heat is Rare

Disadvantages for Minnesota Growers

•Short Growing Season

Year-Round Produce - Is it Possible?

• Potatoes and Squash in Root Cellar?– Sure, we could do that…

• Brussels Sprouts from the field in November?– Yeah, I suppose…

• Radishes and Leeks from ground in December?– With straw mulch and a snow shovel…

• Harvest Lettuce and Spinach in January?– Now that’s just crazy talk!

Striving For Year-Round Produce

• In earlier years, local growers knew ways to grow and maintain winter produce

• Cheap land, free water and inexpensive transportation allowed places like California to supply fresh produce, pricing out local growers

• Now tables are turning with higher land costs, water rationing and high fuel costs

Our Experiences, So Far…

• Like everyone, we’ve always tried to expand our growing in the spring and fall.

• Inspired by Eliot Coleman’s “Four Season Harvest” book – we have pursued a year-round CSA vision

• I will talk about our experiences over the last 3 seasons

Warm Germination

• In cold soil, peas take 3 weeks to germinate• In 80 degree soil, peas take 5 days• Use a warm table to germinate in trays• After germination, move into full sun• Later, place trays on ground for rooting• Radish, onion sets, radish, snap peas

Warm Germination: Our Practice• 6 foot folding table with plastic sheet cover and

2 foot overhang to catch heat• Oil filled radiator for heat underneath table• Germination bed thermostat controls radiator -

set at 75 degrees• Plastic sheet over trays to retain moisture and

heat• Foot square 4” high slotted trays hold 3” soil

Warm Germination: Our Practice• Another method is a germination tent• Uses a mini greenhouse from Menards• Homemade water tray with immersion water

heater keeps temperature constant and humidity high

• Water tray captures condensation

Row Covers - Prevent Frost• Helps block radiated heat loss• Slows down convection cooling• Watch out for Clear and Calm - especially in

Spring when low humidity allows temperature to drop quickly after sunset.

• Find the place on your land that frosts first - monitor it

• I’ve seen frost when air temp was 42 degrees

Row Covers - Keep in Heat

• Plants don’t grow well below 50 degrees• Chemical reaction speed doubles for every

18 degrees of increase• So, with ample sun, plants grow twice as

fast at 86 degrees compared to 68 degrees• Woven fabric is best (prevents overheating),

slitted plastic is okay as well• Over 90 degrees, plants suffer

Row Covers: Our Practice• Woven fabric like Agribon• Anchor with rocks or sections of steel rebar• Monitor weather service (www.noaa.gov)

watch dew point and wind speed - use “Digital Weather Forecast” panel to see predicted values every 3 hours

• In Spring - watch for surprise frosts• In Fall - try to evade the first frost

Greenhouse in High Tunnel

• Build a simple plastic green house inside high tunnel for early spring or later fall use.

• High tunnel provides wind and rain/snow protection, so inside house can be simple frame and plastic

• Can be sealed enough so a simple heater and fan circulation can prevent temps from going too low at night.

Greenhouse in High Tunnel: Our Practice

• We use our tomato high tunnel that already has a frame for securing netting for our tomatoes during the summer.

• Simple channel and wiggle wire to secure plastic.

• Roll up and store inside during summer

Mini-Raised Beds

• 2” wide raised beds made with two 8 foot 4” wide boards with 2” spacer boards

• Set on ground, fill with potting soil• Set in transplants• Warmer than underlying soil• Easy to water (bed holds in the water like a

pot)

Mini-Raised Beds: Our Practice• We use cheap 1/4” thick 4” wide wainscot

pine boards preserved with a sealer• 2” wide cedar boards on ends completes

rectangle and spaces correctly, plus 1 in middle

• Ideal for Jiffy-7 pellet based transplants• Head Lettuce, Kale, Spinach, Broccoli• Pull up beds and store after harvest

Cold Weather Holding

• Many plants hold produce well in cool air• Some hold well even thru freezes• Root crops can be held by mulching• Key is to grow enough produce in late

summer and early fall to have multiple weeks of produce ready to hold when cool sets in

Cold Weather Holding: Our Practice• Beans, Beets - for the last 3 weeks (plantings),

plant twice as many as earlier weeks• Zucchini - last planting, 4 times as much, skip

straight neck squash (not as cold tolerant)• Broccoli - last planting, twice as much• Brussel Sprouts - we’ve eaten them in

December - picked frozen• Lettuce and Spinach in hoop house - good to

15 degrees

Winter Harvest

• We get as much sun as southern France, but no ocean to moderate the climate

• High Tunnel and row covers provide that moderation – create a zone 6 climate six inches off the ground – think southern Missouri

• Heat of the day, plus water in ground, plus row covers keeps the ground unfrozen

Winter Harvest: Our Practice

• Radish from seed• Green onions from bulblets, leeks from

transplants• Bok choi and kale from transplants• Lettuce, arugula, mustard and spinach from

seed or transplants

Winter Harvest: Our Practice

• Ideal start is August 15. Growing pretty much stops end of October.

• In 2012, harvested until ran out in mid-January. Coldest night outside was 12 below.

• In 2013, did not start until Sept 15 (too hot before that). Less growth – harvested until mid-December.

Winter Harvest: Our Practice

• Manage heat early on – can be tricky in early fall

• Water well before freezing weather arrives; needed to hold latent heat, keep up the humidity, and hydrate the plants into the winter

• Use one or two layers of lightweight row cover – easy to manage since no wind issue

Winter Harvest: Our Practice

• Harvest more sensitive crops like radishes before it gets too cold

• Greens and Bok Choi freeze but will be okay – do not disturb when frozen

• Harvest in sunny afternoon when thawed and re-hydrated.

• Watch forecast to plan harvest – need that sunny day!

Winter Harvest: Our Practice

• Monitor for pests – especially aphids. Take advantage of those swarming lady bugs in fall.

• Moderate temperatures can also overwinter pests – not a bad idea to clear, open and expose once harvest done (February?) to prevent this

Hydroponics

• We have unused space (prep and packing area) in winter

• We keep it heated – why not heat with lights?

• We need a jump on transplants in late winter

• Is Hydroponics an answer for more winter harvest?

Hydroponics: Our Practice

• Farmtek 12x12 hydroponic system• 18 fluorescent light fixtures, 2 bulbs per

fixture, about 40 watts per bulb fixture = a 15 amp electric heater

• 18 more fixtures for germination tents. Sufficient to heat our 20x30 prep/pack building in the dead of winter

• Our first year – we’ll see…

Make Hay While The Sun Shines

• Start Earlier - Warm Germination, Row Covers, Mini-Raised Beds,

• Harvest Longer - Row Covers, Cool Weather Holding, Mulch Root Crops

• Into the Dead of Winter – High Tunnel and Row Covers

• Hydroponic Systems

Questions?

• Resources– monarchmfg.com- slotted trays– Menards - mini-greenhouse, lights– farmtek.com - wiggle wire, heat mat

thermostat, row cover, hydroponic– Amazon.com – NorPro immersion (cheap in

price, but not real durable)– trumpeterswanfarm.com - questions