Gardening Tips: September 4, 2013

A New Lawn
Mid-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 too dry to plant grass seed but the showers and storms we had recently have helped that situation. I recorded almost two inches of rain Tuesday night, which was perfect. It is still warm though, so tomatoes and other garden vegetables will continue to ripen.
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.

Chemical issues
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. After spraying the existing vegetation with weed killer, wait three or four days before you till the soil or sod. You will need a pretty powerful rototiller to break up existing sod, but be sure to till it thoroughly or even remove the top layer of sod and till the soil beneath it. Most lawns will benefit from additional organic matter. You can buy a bale or two of peat moss and till that into the top four inches of soil and a bag or two of composted manure will provide all the fertilizer you need, if you till that in at the same time.
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. Soil testing kits are inexpensive. 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. Till the pelletized lime in at the same time you do the peat moss.

Final preparations
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, sprinkle the area with water, which will allow the seed to stick better. 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.