If your lawn is patchy, thin, or has bare spots, planting new grass seed can help you get a thick, lush lawn. A full yard of grass not only looks beautiful but will help prevent weeds from growing.
Whether you’re planting a new lawn, filling in bare spots, or overseeding your existing turf, you’ll want to consider a few different aspects of your lawn in order to know the optimal time to sow your grass seed to get the best results.
Before you plant new grass seed, it’s important to know what type of grass you have in your lawn. Do you have a warm-season turf like St. Augustine, Bermuda, or Zoysia grass? Or a cool-season grass like Fescue or Kentucky Bluegrass? Warm-season grasses tend to grow in warmer climates and cool-season grasses in cooler climates, but this isn’t always the case, especially in transition areas in the middle of the country between cool and warm climates.
Knowing your grass type will be the first step to determining both the timing and selection of your new grass seed. If you don’t know your grass type, DoMyOwn.com’s grass guides or your local extension office can help you with your identification.
Warm-season grass seed should be planted in the spring when the weather is warming up and after the last frost in the area has passed. These seeds germinate best when soil temperatures are between 65 and 70 degrees with daytime air temperatures above 80 degrees. Since warm-season grasses thrive in warm weather, waiting to plant until the danger of frost has passed and your soil warms will help your new seed grow and establish faster. Based on where you are located, this may vary from mid-March through June.
The best time to seed or overseed cool-season grass is in the fall as the weather begins to cool. With the soil still warm from the summer, mild daytime temperatures, and cool evenings, cool-season grass seed will be able to quickly germinate and establish before the first frost hits.
When you plant your cool-season grass seed will depend on your location. You want to make sure to give your seed plenty of time to establish before winter. As a general rule, lay down new seed at least 45 days before first frost is expected in your area.
In the North, you’ll want to seed from mid-August through mid-to-late September. If you live in the transition zone or Southern U.S., you may be able to plant beginning in September and as late as October.
After planting the new grass seed, you will need to water the lawn regularly to encourage growth. The lawn needs to stay moist, but not to the point of puddling, before the seed germinates. Water the lawn 1 to 2 times per day for a few minutes to keep the lawn moist. If the new seeds dry out, they may not grow. Once the seeds germinate and you can see new grass forming, you can reduce watering to once per day. When the grass reaches 1.5 to 2 inches tall and becomes established, you can resume your normal watering schedule.
Depending on the results of your soil test, a fertilizer may be needed to help promote the growth of your new seed. Starter fertilizers are specially formulated to meet the nutritional needs of new grass while it establishes. These fertilizers typically have higher levels of Phosphorus to help promote root development and are typically applied with or immediately after seeding. Refer to the label of the fertilizer for application timing.
Some herbicides will kill new grass growth. Consult product labels for timing information.
If you have any questions on when to plant new grass seed and what products to use, consult your local extension office or DoMyOwn’s lawn care guides at DoMyOwn.com.
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