Warm weather may feel far off, but it’s important that we’re looking ahead to what spring grass seed our lawns will need. In all-natural organic turf care, thick grass is the best defense against weeds. In the Northeast, spring is primetime to top dress and over-seed thin spots. Although, if this spring shapes up like recent years, topdressing and over-seeding will not be an easy task.
Soil temperatures affect seed germination. Seeds will not germinate until the soil temperature reaches 50°F or greater, and soil temperatures run roughly 10°F lower than the air temperature. In recent years, our seeding window has been shrinking as soil temperatures are staying cooler longer. Temperatures have then drastically jumped to a hot summer. We cannot discount these factors when we look at our spring seed selection. When choosing grass seed, recognize the germination time required and choose accordingly.
Types of Grass Seed
Perennial Ryegrass germinates in 5 – 7 days and is useful for quick reestablishment of damaged areas on lawns and athletic fields. Perennial ryegrass does well in soils in the 6.0 – 7.0 pH range. Establishment rate: fast.
Tall Fescue germinates in 7 – 14 days and can have very good drought tolerance. Tall Fescue will also handle more acidic soils in the 5.5 – 6.5 pH range. Establishment rate: medium – fast.
Fine Fescue germinates in 7 – 14 days, and are a shade-tolerant cool-season grass that will do well with more acidic soils in the 5.5 – 6.5 pH range. Establishment rate: medium – fast.
Kentucky Bluegrass can take up to 28 days to germinate under normal weather conditions. This would put new seedlings germinating around the middle of June, and it’s likely that these new plants will not be established before we encounter soil temps favoring the germination of crabgrass seeds. Kentucky Blue produces rhizomes, and is therefore a good choice when over-seeding in the fall. Kentucky bluegrass prefers soils in the 6.5 – 7.0 pH range. Establishment rate: slow – medium.
Given the germination time for these seeds, we recommend using blends higher in Perennial Rye and Tall Fescue for repairs this spring. Both of these grasses are primarily bunch grasses and will not spread much laterally to fill in areas. These blends will provide the best chance of germination and some establishment before the summer heat.
With any spring grass seeding, keep in mind that it can take 1.5 years for grass to become fully established from seed. Without regular watering through the summer, you can anticipate that the newly established grass will have a low survival rate, which is why fall aeration and over-seeding is also critical for lawns. Spring seeding should be approached as a way to minimize weed pressure in bare areas, not as a means to establish a lawn.