The Time Has Come to Seed Cool-Season Grasses

Late August to early September is the best time to overseed cool-season grasses. It may still be a little warm outside, but temperatures will quickly begin to moderate as the days get shorter.

The easiest way to get new seed into your lawn is to core aerate it first before sowing seed across your lawn. Be sure to either wait until a decent rain has fallen or the lawn is watered well before aerating.

The goal is to allow the core tines to penetrate the soil to pull up plugs of soil and leave them back on top of the grass. This opens up the lawn to more air, water and nutrients that will penetrate into the root zone to help build stronger roots. It also provides a great place for seed to come in contact with soil in order survive after germination. Throwing grass seed across a lawn without proper preparation will result in poor or no germination.

You can hire a professional to handle the core aeration for you, or you can rent a core aeration machine and tackle it on your own. Be sure to mark sprinkler heads, buried cables and electric dog fences in advance of using any core aeration machine on your lawn.

New seedlings germinate and grow best when soil temperatures are between 70 and 80 degrees Fahrenheit.  Purchase good quality seed – not a cheap bag of seed you find at a discount store. A good mix of seed will cost around $4 to $8 a pound. You may have to go to a landscape supply store or to a feed store to find quality seed. Many times the seed is available in bulk and you can purchase larger quantities.

Most seeding failures come as the result of putting too much seed in too small of an area and not keeping the area moist for a long enough period of time. Perennial ryegrass will germinate in 5 to 7 days, turf-type tall fescue and fine-leafed fescues will germinate in 7 to 14 days and bluegrass takes 28 days. Once the grass germinates, it will need continual water to develop roots and shoots. Provide ½ inch of water to your lawn each week – more if it remains hot and dry.

Depending on the mix of seed you plan to use, the amount sown per 1,000 square feet range from 3 to 6 pounds. Bluegrass is the smallest of seed, so it contains more seeds per pound. Ryegrass is the next largest, followed by the fine-leafed fescues and turf-type tall fescue. The larger the seed, the more you will need to spread per 1,000 square feet.

After your lawn has been core aerated and overseeded, a fertilizer with an analysis of 16-4-8 or similar should be applied.  In states that require phosphorus-free fertilizers, most allow fertilizers with phosphorus (the middle number on the analysis statement) to be used on newly seeded turf.

Continue mowing as the new seed germinates. You want to make sure the sun reaches the new seed to help it germinate. As far as spraying for weeds, you need to wait until the new grass has been mowed two to three times before spraying for any weeds. If you are very careful, you could spot spray a few broadleaf weeds, such as a dandelion, but do not spray across the entire lawn.

Your local lawn care professional at Spring Green can take care of aerating and seeding needs. Don’t wait, as there is a limited amount of time to get this work completed until it gets too cold for good seed germination.