Minnesota Lawn Care Advice

Restore your lawn with overseeding

Regrow your patchy lawn and restore dead brown spots in your yard with overseeding. Overseeding revives plants damaged by summer heat, heavy foot traffic, and other wear and tear. Here's what our landscape professionals have to say about overseeding your lawn.

What is overseeding?

Overseeding is when you spread grass seed over your existing lawn. Because it's customary to mow grass before it reaches the seeding part of it's lifecycle, we have to add additional seed ourselves in order to replenish worn and thinning spots.

When to overseed your lawn:

In northern climates, spring and fall give the right conditions for overseeding. We prefer overseeding in the fall because weeds have finished their life cycle, but the soil and air conditions are still optimal growing conditions for grass.

The best time is the first two weeks of September. In general, the 15th of September is your last chance for getting seeds on the ground. This gives you about six weeks where you can count on the temperature to cooperate.

How to overseed your lawn:

1. Prepare. Mow your lawn to about 1-1/2 inches and bag the clippings. After mowing, rake to remove debris, dead grass, and loosen the soil. This will allow the seed to come into contact with the soil.
2. Analyze your soil. In order to determine what kind of fertilizer is right for your lawn, test your soil. You can use a kit from a garden center or send a sample to the U of M soil lab. Soil tested at the U of M will not only let you know what kind of soil you have, they will also make recommendations on what amendments to add to your soil, if necessary. Test kits from garden centers and big box stores may not have accurate results, or give you any recommendations on what actions to take. (Here's what the U of M has to say about fertilizer)
3. De-thatch. Grass clippings collect at the base of the plant and form a matted layer called thatch. If the thatch is too thick it prevents water and nutrients from reaching the soil. Break up and remove thatch with a rake before seeding. This allows seeds to reach the soil.
4. Aerate. Core aeration fights compaction and allows water, fertilizer, and oxygen to enter the root zone. This process is best done with an aerator, which can be rented from garden supply or hardware stores. At the end of the process your yard should be littered with 2-3 inch plugs. Leave the plugs (don't rake them up) to give your yard a boost in nutrients as they decompose. Aeration doesn't need to be done every year, but every other year is usually about right.
5. Select and spread your seeds. Choose species that are right for the conditions in your yard. It is shady or sunny? Extra wet? Low maintenance? There is a grass seed or seed blend for every situation. Consult the U of M extension or your local garden center to determine the right variety and quantity for your lawn. Before seeding, cover bare spots with some good black dirt for best results. You can spread your seeds by broadcasting with your hand (no tools required, but not the most consistent), or using a hand held seed spreader or push spreader for even distribution.
6. Water. To revive your lawn, water once or twice a day based on weather conditions. Ideally, the top 2 inches of the soil will remain moist. This encourages deeper root growth which will make your mature lawn more resistant to heat and drought. Sandy soil dries out faster, clay retains water more. Not sure what type of soil you have? Have your soil tested at the U of M, or perform this simple mason jar test yourself.

While it may seem daunting at first, overseeding is a project that anyone can tackle with a bit of research and planning. If you take the time to to do it right, you will be rewarded with a thicker, greener yard. And that's worth celebrating.