When to Seed High Altitude Grass Seed?

Location

• Grass seed grows best when planted at certain temperatures. Temperatures at higher elevations tend to be lower than temperatures at lower elevations. Therefore, you need to adjust your planting times in these areas to coincide with your climate zone, which is based on your annual low temperature. Do not assume what works in the valley works in the highlands.

  Check with your local extension office for information about your USDA Plant Hardiness Zone. There are 11 climate zones in the United States. Generally, the coolest zones are in the North, and the warmest zones are in the South. In high-altitude areas, though, the zone is often much lower than in adjacent lowlands. For example, much of California is in Zone 9, but the highest elevation areas are in Zone 6.

Fall Planting

• According to AllAboutLawns.com, the best time to plant cool-season grasses such as Kentucky bluegrass, fine fescue and perennial rye is between Aug. 15 and Sept.15, when daytime temperatures are 65 to 75 degrees F. Because temperatures turn cold earlier in higher elevation areas, target early to mid-August for planting. You need to give your seeds enough time to develop into mature grass before winter's harsh weather arrives. Immature grass lacks root development, which limits the plant's ability to take in nutrients that sustain it. A poor root system can lead to starvation through the cold winter months.

  The window of opportunity, though, is narrow at higher elevations. Planting too early in the summer months leaves seedlings susceptible to the effects of drought. Follow weather forecasts to make sure drought conditions do not exist before applying seed.

Spring Planting

• Spring planting requires patience. You need to wait until the weather warms enough to ensure that cold blasts and the frost that comes with it is unlikely to affect your seedlings. If you plant your grass seed too early and a frost comes, it could damage your seedlings. If this happens, there's a good chance you'll need to plant them again. Once your seedlings have developed into grass, the plants are less susceptible to the effects of cold weather. Therefore, you want to maximize the speed with which your seedlings develop.

  The best time to plant cool-season grasses is when daytime temperatures reach 60 to 75 degrees F. For many higher elevation cities, it is better to wait until temperatures reach the higher end of the margin. This means applying seed in mid to late May. Your exact date will vary based on your elevation and resulting hardiness zone.