There are four conditions to understand when grass grows:
- Dormancy describes the stage when grass does not grow.
- Seed to Germination describes the growth from new seed to grass plant.
- Active Growth describes the spring and summer months when regular lawn mowing is required.
Lawns beautify your property, protect against erosion and provide a habitat for many animals, insects and pets. Caring for your lawn in spring is important to overall health throughout the year. Your most vital landscaping tool is understanding how the grass of your lawn grows throughout the seasons.
All species of grass have unique growing seasons and dormant months. Across the United States there is a clear line between regions with cool-season grasses in the north and warm-season grasses in the south. Cultivation and care vary slightly between types but dormancy is the primary factor.
All lawns are dormant during the winter months. The ability to go dormant under duress defines a quality grass species. Cool-season grasses will go dormant when temperatures fall below 40 degrees and during dry conditions above 90 degrees. Warm-season grasses typically tolerate higher temperatures. They also tend to be more adaptive than cool-season grasses-halting growth during cold dips and responding when temperatures rise. In spring when temperatures reach a stable range of 60 to 75 degrees Fahrenheit, grass will begin growing.
Nearly every spring, cool season grasses will germinate in very late March and flourish throughout April and May. Regions north of I-70 typically feature cool-season grasses like Kentucky Blue grass, perrenial rye grass and blue fescue. Ground and air temperature trigger the growth of these plants. When the ground temperature reaches 55 to 65 degrees, the roots begin absorbing moisture and ground nutrients. When air temperature maintains 60 to 75 degrees, the grass plant begins to grow. As all of us who live in the cool-season region can attest, once growth begins these lawns are incredibly healthy.
Species like Bermuda grass and St. Augustine grass require much higher temperatures before emerging. Soil temperatures above 70 degrees are needed for most warm season species. When daytime temperatures reach 80 degrees and nighttime temperatures don’t dip below 65 degrees, warm-season grasses will thrive. In southern regions of the United States, these grasses will remain hardy from the first of March through September. Warm-season grasses are a bit more agile than cool-season counterparts. Because these species may stunt growth in response to dips and spikes in temperature, I like to add blend warm season species into sunny spots, high traffic areas and along hills even in cooler regions. When temperatures stabilize, warm-season grass will quickly recover and prevent bare patches.
Spring seed tips
During the spring, germination of new seeds is easier. The conditions in the spring are typically cooler and regular rain helps new seeds germinate.
Whether recovering or planting new seed in your lawn, consider when and what to plant. Many weeds grow like warm-season grasses. So cool-season grass seed is ideally planted in the fall and early spring when temperatures are still mild. The new grass seed will germinate before weeds have a chance to grow. Warm-season grass seed won’t grow until temperatures rise. If these species are planted too early in the season, the seeds may wash away or simply be pushed out by weeds. Also consider planting the right grass for the needs of your lawn. As I mentioned earlier, I like to blend my lawn with a mix of cool and warm season species.