Turf renovation and repair is sometimes harder than starting from scratch, says Kathy Richardson, landscape designer for Grant & Power Landscaping in West Chicago, Illinois. “You’re typically trying to match new turf to the turf already in place; it’s hard to get it to match up and look as though it belongs there. If the homeowner started with a seeded lawn, it develops a much better turf over several years than a sodded yard does.”
Whether you’re installing turf on new construction or installing landscape elements on an existing lawn, it’s important to have turf renovation methods that work for turfgrass in your area of the country.
“The main challenge with turf renovation in the Pacific Northwest is the typical development scenario where a developer comes in and strips off the topsoil to about 95 percent so it can support the structure,” says Will Bailey, landscape management operations for Signature Landscape Services in Redmond, Washington. “Then they come back with a 4-inch layer of topsoil over the compacted fill dirt; that’s a recipe for drainage issues down the road because the water has nowhere to go.”
Know your turfgrass
Between October 15 and mid-June of each year, the Seattle area gets about 60 inches of rain. When you layer different soils, such as topsoil over compacted fill, the topsoil has to be saturated before it will drain to the layer below. “We face serious topsoil dept challenges,” Bailey says. “It’s so wet here, that poor soils limit our effectiveness onsite.”
Signature Landscape Services focuses on improving drainage and the stability of the surface so they can grow good turf without it shearing off from mower tires or from people walking on the slope.
On new construction jobs in the Chicago area, Grant & Power Landscaping often installs hardscape elements such as paver patios, outdoor kitchens and outdoor living spaces. The lawn has to be fine graded either before or after the hardscape work, depending on the situation. “Sometimes we have to wait several weeks to get final grade approved,” Richardson says. “That’s one of the hardest things about turf renovation, because during the approval process weeds start to grow and you’re making more work for yourself.”
In existing landscapes, if you’re putting in a patio you have to over-dig the area where you’re laying the brick or stone to ensure it gets strong placement, Richardson explains. Plywood is usually put down across the yard to bring in small pieces of equipment – cutting down on a lot of ruts and turf damage on an existing lawn. “It’s usually a simple repair if we’ve taken measures to protect the turf,” Richardson says. “Sprinkle a little grass seed and some topsoil, and it usually grows back in nicely.”
Have a technique
“Our most common first step is to aerate,” Bailey says. This includes two passes with a core aerator and a topdressing with a 60-percent sand/40-percent compost mix. He says the benefit is hard to see sometimes in the first year, but after three to five years you’re providing a way for the water to drain away from the surface and into the bottom layer.
In conjunction, overseeding is done to improve the grass species. The most common Pacific Northwest grass species are perennial rye and fine fescue. Over time, as with any turf, it reaches a climax situation where non-desirable grasses infiltrate. “When we overseed, we’re trying to fill in areas where weeds have been or areas that were killed or damaged by crane fly, thereby increasing the desirable species within a turf,” Bailey says.
A lot of seeding Signature Landscape Services provides is done with a slice seeder, which has a vertical raking implement on it much like a dethatcher. “We don’t put a lot of energy into raking thatch off,” Bailey explains. “We mow with collection-type mowers to pick that up. It’s not a big problem if we’re addressing the topdressing issue regularly because it provides an insulation layer and nutrient microbial basis.”
Some homeowners make the mistake of spraying chemicals on their lawns, thinking it won’t affect the grass itself. There are certain chemicals that are for specific issues, so sometimes it ruins the lawn and it needs to be replaced. It’s important to read chemical instructions before application.
“We had one client who had a lot of invasive mint in their yard, and had removed some of it and applied chemicals to get rid of it,” Richardson says. “They needed that part of the yard repaired with turf, but because it is a very invasive plant, we spent a lot of time trying to remove the remnants before we could repair the lawn.”
Both companies agree some turf damage is inevitable, but “We build everything out, do our cleanup, and turf repair is the last thing we complete,” Richardson says. “Usually sod is placed to finish the job, and the customer can enjoy their landscape right away.”
