If you plan to start your new lawn from seed, it is critical to know the best temperatures for seed germination. Before you purchase seeds and prepare your lawn for planting, research the best seed varieties for your particular climate zone and time of the year, and keep in mind that some varieties may do better when planted with plugs or sod.
Warm-season grasses keep your lawn green during the hot and dry summer months. Plant seeds in mid-spring or early summer. Keep in mind that some warm-season grasses, including some cultivars of bermudagrass and St. Augustine grass, don't do well when planted from seed. The soil temperature range for most warm-season grasses is between 65 and 75 degrees Fahrenheit and sometimes higher. Optimal air temperatures for warm-season grasses are 80 to 95 degrees Fahrenheit.
Start cool-season grasses in the late summer and early fall, when temperatures are warm and the chance of rainfall is higher than usual. Seed that is sown in the spring is almost certain to fail, according to the University of Missouri Extension. Air temperatures for cool-season grasses should be between 60 and 75 degrees Fahrenheit, with soil temperatures between 50 and 65 degrees Fahrenheit.
Temperature is one of the most important factors in grass-seed germination, but there are also other crucial elements to remember. Water grass seed lightly to avoid drowning the seeds or washing them away from the planting site. If the seeds receive a lot of water from rainfall, take that into account when you decide how much and when to irrigate. Preparing the soil site by weeding, tilling, fertilizing and grading if necessary, will also go a long way toward preventing problems.
Temperature requirements can make planting grass from seed seem intimidating, but with adequate preparation and planning, it's possible to establish a healthy lawn. Additionally, costs tend to be significantly lower when the seed is planted at the right time and temperature. Other alternatives, such as sod and plugs, may be more feasible if you missed the window for planting grass from seed. Sod may also require more water than seed, since grass seeds need minimal moisture before they emerge.
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