Renovate or reestablish?
Removing existing turf and starting from scratch can be a scary proposition for a lot of clients. Typically, though, if their property has less than 60 percent of desirable turf covering the ground, they should consider reestablishment.
Renovation is the less severe overseeding of turf to achieve a more substantial lawn through scalping with a mower, and any combination of aerating, verticutting, and/or topdressing to maximize seed-to-soil contact. It can be a less intimidating option for those clients who can’t commit to a complete overhaul.
“There is no better time to give your cool-season lawn the attention it craves than in the late summer to early fall.”
2. ’Tis the season
“There is no better time to give your cool-season lawn the attention it craves than in the late summer to early fall. The cooler growing season provides turf plants a chance to regenerate themselves,” says Bruce Hellerick, senior horticulturist for Brickman’s PennDel Division. Weeds begin to wane and will pose less competition for seedlings, giving them opportunity to get well-established before cold weather sets in.
3. Out with the old
Killing out what’s left of existing turf is easily accomplished with a non-selective herbicide, such as RoundUp or Kleenup. Zac Reicher, Ph.D, professor of turfgrass science at the University of Nebraska, says that multiple applications two weeks apart may be necessary for tough-to-control grasses like nimblewill, but difficult weeds like quackgrass may never truly be controlled.
4. Timing is everything
Wait at least three days before taking the next step in reestablishment if you’ve treated the site with a non-selective herbicide. If you can wait longer, even better. “Allowing the existing dead grass to decompose for a month or more makes the next step easier and allows for repeat applications of glyphosate to ensure complete kill,” advises Reicher.
5. Prepping makes perfect
The type of soil you’re working with will define how you prepare the area for new seed or sod. Soils that aren’t compacted and that don’t have thatch: Use an aerator to expose the soil. “A power rake set to cut 1/8 to ¼ inch into the soil also will work well,” says Reicher.
If you have good soil but a thick layer of thatch: Use a power rake to get rid of as much thatch as possible. A sod cutter may be necessary for thatch that is more than an inch thick, and Reicher says that you may even need to rotary till the soil, turning under the thatch. And if it is a clay, turning in this organic layer will help improve the soil.
Compacted soils present the toughest challenge. Start by tilling the soil 4 inches or more then raking the surface smooth. Allow it to settle for a week or two, irrigating the area and compacting slightly with the wheels of a utility tractor or other implement, suggests Reicher.
6. Making amends
If you’re working with heavy, clay soils, introduce compost by tilling it into the site. Reicher recommends applying an inch of compost, tilling, then repeating, tilling in a different direction to insure uniform incorporation of a few inches of compost.
7. To seed, or not to seed
In most cases, seeding is the more practical way to go because it’s less expensive for your customer. However, there are situations where sod works better, especially in areas with a lot of traffic or high visibility.
If you do seed, follow up by lightly raking the soil to incorporate the seed in the top ¼ inch, says Reicher, and roll the area with a light roller to ensure seed-soil contact.
8. Don’t forget fertilizer
Just before seeding, apply a starter fertilizer. If you’ve done a soil sample test, fertilize to those recommendations. If not, Reicher recommends using 1.0 pounds P2O5/1000 square feet.
9. Water works
Irrigation is a critical component to establishment. Light, frequent watering is the rule, which could mean irrigating several times a day.
10. Take care
When the seedlings begin to grow, mow at 1.5 inches until they have been cut at least two times. “After that, raise the mowing height in ½-inch increments over the next three weeks until a normal mowing height of 3 to 3.5 inches is reached,” says Reicher.
Apply the starter fertilizer again at four weeks after germination, using the same rate as specified above.
Reicher advises against applying herbicides for broadleaf weeds until after you’ve completed the second mowing of the seedlings. However, there are newer herbicides like QuickSilver, SquareOne, or Tenacity that are safe on new seedlings. As always, follow the instructions on your herbicide label.
Fixer-upper
If your client can’t stand the thought of a complete reestablishment of turf, there are some things you can do to improve the overall appearance and health of turf, says Bruce Hellerick, senior horticulturist for Brickman’s PennDel Division. Here is what he recommends for clients who opt to not do a complete renovation.
• Have the soil tested by a reputable lab to determine proper pH and corresponding lime requirements to ensure good uptake of existing nutri- ents already present. Lime and fertilize only as necessary.
• Core aerate the soil, preferably in two-to-three directions and apply top- dressing in especially thin areas to add organic matter and improve soil struc- ture. “This process removes ‘plugs’of soil from the turf, which helps to reduce the thatch layer and improve air, water and fertilizer penetration into the soil,” says Hellerick.
• Top dressing the turf areas with ½ to 1 inch of organic compost will intro- duce beneficial microbes, organic material and low levels of slow-release fertilizer.
• Broadcast seed in areas that have more than 60 to 70 percent desirable turf species and use a mechanical slit seeder in areas that have less than 60 percent to insure good soil-to-seed contact and promote the best and quickest germination.
• Apply a starter fertilizer to provide immediate nutrients for newly germi- nated grass seedlings to aid in the lawn’s root development.
• Provide adequate irrigation to renovat- ed area to keep the seedbed moist but not too wet. The turf should receive approximately 1 inch of irrigation or rainfall each week.
Failure to thrive
There are a number of reasons turf withers away. When helping your customers decide if they need to renovate or reestablish, it’s beneficial to explain what went wrong in the first place, especially if it’s something they could correct in the future.
Aerating turf is an essential step. It loosens soil and provides oxygen to the roots of the grass.
• Mowing too low
• Over-irrigation
• Poor or compacted soil from initial construction practice
• Thatch accumulation
• Excessively wet, dry or shaded areas
• Disease and insect stresses
• Too much competition from crabgrass and other weeds
• Improper or poor quality grass species used at point of installation or species of grasses are out of balance
• Improper soil pH, causing nutrient deficiencies