Overseeding is the type of home improvement hack we love. This process simplifies an often difficult and frustrating chore — growing a lush green lawn — and makes it both doable and affordable for the average homeowner.
What is overseeding all about?
You begin with one less than lovely lawn (yours perhaps?) that has been damaged or burned by foot traffic, heat, insufficient water, and good old Father Time. Instead of asking your landscaper to rip it all out and start over from scratch, you have him add grass seeds of a species that’s compatible with your existing lawn, so that they'll fill out patchy, dead spots and give your property a smooth, healthy look. FRINGE BENEFIT: The thick coat of turf that results from overseeding will help keep weeds at bay.
Prep for overseeding
Although overseeding is a simple procedure, it will go best if you take care of some easy DIY prep work beforehand. A month in advance, stop using fertilizer. Prepare your lawn soil by going over it with a core aerator (which can often be rented from your local home center), so that the new seeds will be able to take root readily; aeration works best after a rainfall, when the ground is still moist. You might need to dethatch as well if you have a layer of thatch more than ½ inch thick. Then cut the existing grass to a uniform height of 1-2 inches, removing the clippings afterwards, for optimal water absorption. Finally, spread a thin layer of compost to add nutrients to the soil.
Choosing the right type of seeds
Overseeding with the right species is vital for the best appearance. Otherwise, your lawn may be filled out, all right, but with two very different colors and textures of grass. Even more important, the grasses may have widely varying needs and tolerances — for water, fertilizer, sun, heat, etc. To find out what type of grass you already have, you can look it up online. Many university extension services publish identification guides. Although overseeding with exactly the same type of grass is not necessary, the seed species should be compatible. Consult a good landscaper in your area for more help.
The overseeding process
Check the label to find out how much seed to use per square foot. Broadcast the new grass seed as evenly as possible over the surface of your lawn-to-be, to avoid bare patches. For a small yard, it’s fine to do this part by hand or with a handheld rotary spreader, but for a larger area, you’ll need more powerful equipment: A walk-behind rotary spreader or a drop spreader. (You may already have one of these on hand for use with fertilizer.) Then rake the seeds into the soil — gently does it.
Water the lawn immediately after overseeding. After that, continue to keep the ground moist by sprinkling it lightly 2 or 3 times a day for the next few weeks, till the grass seeds have germinated. Don’t soak the soil, though, or your new crop may end up with root rot. Once the sprouts are established, switch to less frequent, deeper waterings. You may want to apply a starter fertilizer, particularly if your soil is low in phosphorus. Don’t cut the grass overly short before it has time to establish itself (8-10 weeks).
Best time for overseeding
The ideal time to overseed depends on the kind of grass you have in your lawn. Warm season grasses (commonest in the southern states) should be overseeded in the spring through early summer, while cool season grasses (usually found in the northern U.S.) benefit most from overseeding in the late summer to early autumn — the recommendation is about 6 weeks before the first frost is expected. If you missed that window and would like to improve your lawn this year, overseeding cool season grass in spring will also produce results.
— Laura Firszt writes for networx.com.