Time to Seed Lawns
Over the past week there has been a little more moisture and somewhat lower temperatures. As we head into September, these conditions are ideal for cool season grasses like tall fescue to germinate. The best results for establishing or renovating lawns with a cool season grass occurs when seeding before the end of September. Keep in mind, spring established tall fescue is more susceptible to fungal diseases, drought, heat and weeds. Spring seeding is not like to result in a year long stand of healthy tall fescue.
The best growing conditions for young seedlings are when soil temperature is greater than 60 degrees and air temperatures range between 70-80 degrees. If you can not be on-time when planting, it is better to seed earlier than later. Tall fescue may exhibit thin turf stands going into the winter if seeded in less than ideal conditions. If seeding is postponed until October there is a good chance of slow and even low germination. A tall fescue seeding rate of 5-6 pounds of seed per 1,000 square feet is recommended. Germination can be expected within 7 to 21 days if there is suitable moisture and soil temperatures.
Cultivar selection is extremely important. There are many cultivars on the market. Recommendations for specific cultivars can be found at NC State University’s Turf Files or in the NC State University publication “Carolina Lawns”. The cultivar name can be found on the seed bag label. If you buy a tall fescue blend, try to select one with at least one of the cultivars from the list of recommended cultivars from NC State University. These are recommended for North Carolina and have proved to be of the highest quality for our area. It is common to find Kentucky bluegrass in the mix. It provides a darker color and finer texture to the mix but keep in mind it typically does not hold up well in the heat of summer. It begins to turn brown with our high summer temperatures leaving brown areas in an otherwise green lawn. Also, it is not a good idea to add ryegrass to the mix.
The seed label will list the grass cultivars included in the mix. Look for a germination rate percentage of 85% or higher. The higher the germination rate, the more seeds that will come up. The value for percentage of weed seed is also an indicator of the quality of seed in the bag. Choose mixes with very low weed seed levels. Ideally, percentage of weed seed should be less than 0.25%. The label will also list the sell-by date. The fresher the seed the higher the germination rate. Choose seeds packaged for sale this year or next year.
Soil areation is recommended before seeding to reduce soil compaction. One of the most important things for good germination is having good soil to seed contact. Without this, germination may be spotty. Getting the right amount of moisture is crucial as well. The core aerification holes will capture seed and hold moisture – as a result of the tall fescue, seedlings often come up as a tuft of turf from aerification holes. It is always recommended to take a soil test.
Soil samples can be sent to North Carolina Department of Agriculture and Consumer Services to be analyzed and are free until November. Results will help identify the correct amount of fertilizer and lime to apply. If this has not been done before grass is sown, NC State University provides general fertilization practices that can be followed. They can be found in the Carolina Lawns publication.
As mentioned earlier, adequate moisture is crucial. It is important to keep the top 1.5 inches of soil moist after seeding. This may require light watering once or twice a day for 7 to 21 days depending on your soil type and weather conditions. As the seedlings grow and root, water less often but for longer periods, working up to the recommended fall irrigation rate of 1/4 to 1/2-inch water per week (via rainfall or irrigation). The best time to water the germinating lawn is early morning. This helps reduce water loss due to evaporation. Resist applying “weed and feed” or herbicides until the grass has been mowed a minimum of three times. These product could damage seeds and the young seedlings. If applying herbicides to kill weeds before seeding, be sure to check the label for any waiting periods that should be followed before sowing new seed.
Tall fescue needs to mature before winter and have few weeds present to prevent competition. A proper mowing height of 3.5 inches should be maintained to provide the best growth conditions. This height helps minimize the presence of diseases and weeds. Begin mowing newly seeded fescue when it reaches 4.5 inches in height. The first time can be clipped back to 3 inches. The mowing frequency will depend on how quickly the turf grows. This will depend on the temperature, fertility, and moisture levels. There is no need to cllect the clippings. They are beneficial by supplying nutrients back into the soil for the grass to reuse. This action alone can reduce the need for fertilizer by 20-30 percent. What are you waiting for? September is almost gone. Get to work in your lawn.