By Dr. Leonard Perry Extension Nursery and Greenhouse Crops Specialist University of Vermont
Your lawn has just survived another long winter. In order to restore it to its former lush, green glory, it will need to be raked, renovated, repaired, and fertilized.
First, make sure there is good drainage. You cannot grow grass in standing water. Drainage may consist of ditches or, if underground, drainage pipe or tiles. Then rough grade the area.
Add six inches of topsoil, if needed. A normal, well-drained subsoil may be adequate if amply fertilized. This may be a reasonable gamble unless subsoil is poor. If it is, add organic matter. Figure on three large bales of peat moss per 1,000 square feet. Then mix it thoroughly into the top six inches of soil. Using any less than this amount of organic matter will have little impact on the condition of your soil.
You may need to add limestone if the soil acidity or pH is below 6.0. To find out, have your soil tested by the Agricultural and Environmental Testing Laboratory at the University of Vermont (802-656-3030) or other reliable laboratory.
Prepare a smooth seedbed free of stones, hollows, and ridges. Raking off the old leaves, sticks, and other winter debris gives your lawn a chance to breathe, as well as makes it easier to repair and reseed.
Broadcast a complete fertilizer or one of the commercially mixed fertilizers specific to lawns. The exact grade is not important if you use enough to supply two pounds of nitrogen per 1,000 square feet. This translates to 40 pounds of 5-10-5 (nitrogen-phosphorus-potassium) or 20 pounds of 10-10-10. This is double the usual lawn maintenance rate.
Uniform application at the proper rate is essential for good end results. If you are using a spreader, follow the setting on the fertilizer bag or ask your lawn and garden dealer for the proper setting.
If you are reseeding or sodding the lawn, the earlier you do it in the spring the better. Remember to prepare the seedbed well, and water the lawn thoroughly. A less frequent, heavy soaking of the lawn is better than frequent, light waterings, but don’t let the germinating seeds dry out initially.
When reseeding, choose the right mix for your growing conditions. Zoysia, for example, is not a good choice for northern New England as it will turn brown in hot weather. A Kentucky bluegrass-red fescue mixture is ideal. Choose one with 55 percent or more Kentucky bluegrass for sunny lawns in good soil. For dry soil, sun or shade, use a mixture with 65 percent or more of red fescue. Avoid any mixture containing bentgrass or tall fescue or more than 15 percent ryegrass.
Broadcast seeds with a mechanical spreader using three or four pounds per 1,000 square feet. Any more than that is wasteful.
Rake the seedbed lightly, using just the tips of the rake teeth. Go over the area with a lawn roller if convenient. Sprinkle the soil gently, and keep it moist until the seeds germinate.
Mow once the grass starts to grow. Grass kept at a height of two to two and one half inches can withstand heat stress better than closely cropped grass. This mowing height encourages deep rooting, so you don’t have to water or fertilize as often.
A healthy lawn is the best cure for weeds and pests. This includes proper culture. If problems occur, such as insects and diseases, check with your local garden center for answers. Homeowners in Vermont and northern New Hampshire also have the option of calling the toll-free UVM Extension Master Gardener Hotline at 1-800-639-2230 for a diagnosis of the problem and best solution.
Be aware that if you are using a combination fertilizer and herbicide, this may be taken up by the tree and shrub roots under the lawn and injure them, too. Or if you use residual weed killers that linger in the soil to prevent future weed growth, these may kill many soil microorganisms. This sometimes results in poorer soil, and thus, poorer lawn growth and vigor.
If applying weed killers, be sure to properly identify your weed problem before you select an herbicide. Then select the least toxic product for the job, looking at application rates and potential toxicity to plants, animals, and humans. Read and follow all label directions carefully. Always use these products judiciously to avoid contamination of water supplies and lakes, streams, and other surface waters.
Lawn pests, such as chinch bugs and Japanese beetle grubs, can be a problem in northern New England. However, control of these grubs is usually ineffective when done in the spring.
Your local garden supply store will be able to answer many of your lawn care questions. For special lawn treatments such as vertical cutting, dethatching, or coring to reduce soil compaction, consult a lawn care professional.