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““Rehabbing Troubled Rehabbing Troubled Lawns”Lawns”
Rob Golembiewski, Ph.D.Rob Golembiewski, Ph.D.
OSU Oregon State University
Reasons for Turfgrass Failure
Improper cultural practices Drought, heat, or cold stresses Weeds, insects, or diseases Excessive thatch Unfavorable growth environment (shade,
poor soil conditions) General neglect, abuse, or overuse
Turf Improvement Programs
1.Initiate a program of sound cultural practices
2.Renovate turf by planting into existing live or dead vegetation
3.Totally reestablish the turf area
Assessment
Turfgrasses present Soil conditions (fertility, pH, and
drainage/aeration) Thatch levels Environmental conditions (light quanity,
quality, and duration) Existing perennial grassy weeds
Program 1 - Sound Cultural Practices
Turf has many acceptable characteristics, but in undesirable condition
Turf areas brought to acceptable quality by altering turf management practices
Successful Program
Existing turf must have: acceptable turf species/cultivar adequate density (potential for) acceptable soil conditions thatch level of ½” or less small number of perennial grassy weeds
Implementation
Integrate the following practices to bring turf into desired condition:mowingirrigationfertilizationcultivationpest control practices
0.5” 1.0” 1.5”
.5” 1.5”
0.5” 1.0” 2.0”
Unfertilized Balanced NPK + Fe
Balanced NPK
Program 2 – Partial Renovation
Often, poor turf requires more than improved cultural practices
Planting new seed into existing live or dead turf provides better turf appearance, density, disease/insect resistance, wear tolerance, and shade/drought tolerance
Successful Program
Should have proper: soil drainage/aeration pH fertility thatch levels less than ¾” small number of perennial grassy weeds if large number, apply nonselective
herbicide
Implementation
1a. Overseeding into live turf, mow short and remove debris to reduce canopy
competition for germinating seeds
1b. Overseeding into dead turf, use nonselective
herbicide to kill vegetation then mow to remove debris
Implementation
2. Open soil to enhance seed-soil contact via: hand raking vertical mowing core aerification slit seeding
3. If not slit seeding, broadcast seed
Vertical Mowing
1. Rotating blades physically extract thatch.
2. Blades should be set 1/8 to 1/4” soil depth.
3. Traverse area in at least 2 directions or until 30% of soil is exposed.
4. Seed applied by broadcasting or slit-seeding.
Core Cultivation
1. Hollow cylinder cones mechanically forced down into turf and soil plug is removed.
2. Removal of cores exposes soil which provides a mean for seed-soil contact.
3. Seed usually applied
by broadcasting.
Slit Seeding
1. Disk-like device slits the turf and seed is deposited.
2. Method most effective for obtaining good seed-soil contact.
3. Should be done minimally in 2 directions for effective coverage.
Broadcast Seeding
1. Not very successful method for good germination.
2. Spreading seed on a non-renovated turf results in little seed-soil contact.
Implementation
4. Incorporate seed with a drag mat or rake
5. Mulch
6. Irrigate daily until germination
complete
7. Mow once turf at intended height of cut
Program 3 – Complete Renovation
Sometimes turf so poor or the environment is unsuitable to support turf growth
Successful Program
This drastic method necessary when: soil conditions unsuitable to sustain turf
growth thatch levels greater than ¾” and
uncontrollable existing vegetation unacceptable and can’t
be improved
Implementation 1. Use a non-selective, short residual herbicide
like glyphosate (Roundup) or glufosinate (Finale) to kill existing turf and weeds
*Effectiveness of herbicides enhanced by: a. Skipping a mowing prior to treatment
b. Apply to actively growing turf
Implementation
2. Correct soil pH, drainage, and/or fertility problems by properly preparing the planting bed
3. Seeding or sodding can be initiated 3-5 days after treatment with non-selective herbicides
Post-Renovation Care
Once renovated turf has been seeded, turfshould be maintained as if it was a newly
established turf
Complete renovation: Kill/dethatch/reseed
Partial renovation: Dethatch/overseed
17 days after planting
Sod
SeedDethatched
SeedKilled/
dethatched
Summary
1. When turf unacceptable, determine reason for decline, select and implement program for upgrading turf
2. After turf improved, maintain sound turf management
program
Contact Information
Rob GolembiewskiOregon State University4017 ALS BuildingCorvallis, OR 97331
Phone: (541) 737-5449Email: [email protected]