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when do lawn weed seeds germinate

Whether you’re repairing bare spots, overseeding an existing lawn or starting from scratch, you can generally expect grass seedlings to emerge within seven to 21 days when grown under proper conditions. It may take another three to four weeks of growth before grass is long enough to mow. For fall-planted seed, this can mean waiting until spring for your first mowing. Some grasses, such as Zoysia grass, may need several months of growth to fully establish.

1. Mugaas, R. and Pedersen, B., “Seeding and Sodding Home Lawns,” University of Minnesota Extension.

Even when you plant your grass seed at the best possible time, your lawn still needs help to thrive. Whether this is your first lawn or you’re the neighborhood expert, take some advice from turf professionals and get to know your grasses and your soil before you start seeding. Follow through on best practices for preparing and planting, and don’t neglect traditional tasks, such as fall lawn care, that help keep your grass and soil healthy, well-nourished and ready to support new growth.

Why Spring is Best for Warm-Season Grasses

Newly planted seed needs consistent soil moisture, and fall planting offers benefits on that front, too. Fall typically brings more precipitation, which lessens the chance that cool-season seeds may dry out, and reduces the need for extra watering on your part. Using premium drought-tolerant, water-conserving grass seed products, such as Pennington Smart Seed and Pennington One Step Complete, lowers the risk of problems even more.

Proper timing allows all types of grass seedlings to root well and get established before natural stresses hit. What that looks like in your lawn can vary depending on your grass type, your growing region and the conditions in any given year.

2. Patton, A. and Boyd, J., “Seeding a Lawn in Arkansas,” University of Arkansas Cooperative Extension Service.

Several distinct advantages make fall the best time to plant cool-season grass seed. In early autumn, the soil is still warm from months of summer sun. This combination of warm soil, moderate day temperatures and cool evenings encourages fast germination and establishment of newly sown cool-season grass seed.

For both pre- and post-emergent herbicides, timing is critical. For post-emergent herbicides, you’ll have the best success spraying young, actively-growing weeds. Mature weeds may require repeated applications for total kill. Most post-emergent herbicides should not be applied to dormant lawns. If applying in spring, wait until the lawn is actively growing and has been mowed at least twice.

What Is A Weed?

Fact: Many perennial grassy weeds form rhizomes, fleshy roots that resprout if left behind in soil during hand-weeding.

A weed is a plant that’s growing where it’s not wanted. Weeds aren’t something you plant intentionally; they just appear. Often they grow vigorously, outpacing and overrunning desirable plants. There are several types of weeds:

Pre-Emergent Herbicide: Prevents seeds from germinating or kills germinating seeds before seedlings emerge from soil; must be applied before weed seeds germinate. A common example of a pre-emergent herbicide is a Crabgrass preventer, which prevents Crabgrass seeds from establishing new plants.

Fact: Annual weed seeds can lie dormant in soil from 4-40 years.

Perennial Weed: Lives for two or more years; plants grow as long as conditions are favorable and frequently die back to soil level with hard frost; new growth emerges at the start of the growing season, originating from roots or stem remains; in warmer regions, some perennial weeds can be green year-round.