Gardening Tips: August 27, 2014
A New Lawn
This is my annual lawn column. We have had a great summer season, with just enough timely rainfall to keep the grass green, but not so much rain as to turn it into a jungle. Mid to late August is the best time to completely redo or establish a new lawn in our part of the world. It takes at least four to six weeks of good weather for desirable lawn grasses to become fully established. The grasses we grow in the Northeast are known as “cool season” grasses, which means they grow best when soil and air temperatures are in the 60s and 70s. Up until earlier this week conditions had been a little too dry to plant grass seed, but the showers and storms we had recently have helped that situation.
Before you go out and buy grass seed, you should evaluate your existing lawn to see if it is necessary to start from scratch or whether a renovation will suffice. If your lawn is more than 50 percent weeds or undesirable grasses, it may be best to start over. A properly planted and cared for lawn should last indefinitely. Most broad-leafed weeds such as dandelions, clover, ground ivy, plantain, violets, Shepard’s purse, chickweed, wild thyme and dollar weed can usually be eradicated with several treatments of broadleaf lawn killers containing 2-4 D and other chemicals that do not affect grasses. Grassy weeds, like crabgrass and tall fescue are unharmed by these chemicals. If they are the main problem, you may have to kill off all the existing vegetation with a non-selective weed killer such as glyphosate (Round Up and others). If you do decide to use one of these non-selective weed killers, make sure it is not a product that is designed to prevent any new growth for several months. The chemicals in these products will prevent the grass seed from growing as well.
After spraying the existing vegetation with weed killer, wait three or four days before you till the soil or sod. The grass and other weeds will still appear green, but they will be dead. You will need a pretty powerful rototiller to break up existing sod, but be sure to till enough to break it up completely, or even remove the top layer of sod and till the soil beneath it. It is sometimes a lot easier to just remove the top layer of sod. If you do this, you will not need to use any chemicals to kill it off. Just shake out as much soil from the roots as you can and compost the sod.
Test for PH
If you have not applied lime in many years you should have the soil tested for pH to see how much should be applied before you do anything else. Local offices of Cornell Cooperative Extension perform this service for a small fee and some garden centers may do it for free. Apply no more than 100 pounds of pelletized lime per 1,000 square feet at any one time. You can apply a second dose if warranted in a couple of months when the grass is well established. Broadcast 10 pounds of 10-10-10 fertilizer or the equivalent per 1,000 square feet and till that in with the lime, if needed.
After raking the newly tilled soil smooth, you can broadcast the grass seed. The best grass seed for our region will be a mixture of several different types. For lawns in full sun, chose a blend that is mostly Kentucky Bluegrass with some fine fescue and perhaps some perennial ryegrass included. For somewhat shady areas, choose a blend that is mostly fine fescues. Avoid annual ryegrass since they will die with frost. Buy good quality grass seed and apply at the rate specified on the bag label. Do not over apply the seed because this may allow the less desirable grasses to become dominant.
Before seeding, lightly sprinkle the area with water, which will allow the seed to stick better. After the soil dries out, if possible, roll the grass seed with a rented roller to insure good soil to seed contact. Mulch the newly seeded area with good quality straw that is free of seeds. Do not use mulch hay or any other type of hay since that will completely ruin your efforts. Clean straw should have no evidence of any seed heads whatsoever. Apply about one bale per 1,000 square feet. You should still be able to barely see the soil beneath the straw mulch. You will have to keep the newly seeded lawn moist until the grass is up and growing but don’t blast it with a garden hose and risk washing away the seed. It will take two to three weeks for most of the seed to emerge. Do not mow it until at least 60 percent of the new grass is more than three inches tall. Generally you will not need to rake up or remove the mulch. If all goes well, your new lawn will be fully established by mid October.