Solved! How Long Does Grass Take to Grow?
Your perfect lawn is right around the corner. Here’s all you need to know about growing grass from seed.
Q: I recently had work done in my yard that left a large area of bare soil. If I reseed the area, how long does it take to grow grass?
A: We all want a good-looking lawn around our homes, but not everyone wants to spend hundreds or even thousands of dollars installing sod. Planting grass seed is a budget-friendly way to repair a damaged lawn or establish a new lawn. Although starting from seed won’t give you immediate gratification, in favorable conditions grass grows from seed to lawn in about two months.
Cool-season grasses grow fast.
The fastest grasses to grow from seed are the cool-season grasses. These grasses grow best when soil temperatures are between 50 and 65 degrees Fahrenheit, which corresponds with air temperatures between 60 and 75 degrees. With proper care, all of these grasses are capable of growing from seed to lawn in as little as 30 days.
- Annual or Perennial Ryegrass, 5 to 10 days to germinate
- Kentucky Bluegrass, 7 to 10 days to germinate
- Tall fescue, 7 to 12 days to germinate
Warm-season grasses take more time.
Due to longer germination time and the amount of time it takes for root development, warm-season grasses grow more slowly than cool-season grasses. As you may expect, warm-season grasses like it hot. Cold weather can interrupt the germination process and possibly kill young grass plants. For fast germination, warm-season grasses need soil temperatures between 60 and 75 degrees Fahrenheit, and daytime temperatures consistently above 80 degrees. While these grasses may be tall enough to mow within two months of seeding, full, dense establishment takes up to a year.
- Bermuda grass, 10 to 30 days to germinate
- Zoysia grass, 14 to 21 days to germinate
- Centipede grass, 14 to 21days to germinate
- Buffalo grass, 14 to 30 days to germinate
How fast your grass will grow depends on several factors other than the type of grass you are planting. Sunlight, time of year, site preparation, and irrigation all affect how quickly grass seeds sprout and become established.
Grass needs full sun to grow best.
Grass grows best in full sunlight. As soon as the grass seeds sprout, the tiny leaves begin using that sunlight to make energy that grows deep roots and lush leaves. If there’s plenty of light, grass plants grow full and fast. If there is too much shade, the lawn will grow sparsely. Before planting grass seed, make sure the area receives at least six hours of full, direct sunlight each day, or choose a shade seed mix if that’s not possible.
Plant grass seed at the right time of year.
Match the time of year with your choice of grass seed.
- Plant cool-season grasses while temperatures are cool, and when they will remain cool for a couple of months so that the lawn can become well established before the weather heats up. For many of us, that means late summer or fall, or possibly later winter. For some it means spring.
- Warm-season grasses, on the other hand, should be planted in late spring or early summer. They take a long time to germinate, and that time must not be interrupted by a late cold snap. But don’t wait too long! These heat lovers need to be well established before the first frost in fall.
Prepare the soil before planting and protect the new seeds.
Whether you are repairing an existing lawn or planting a new one, site preparation is key. Kill any existing weeds, but take care: Chemical weed killers have wait times between application and seeding new grass. Each one is different. Follow the manufacturer’s directions. Create a hospitable root zone for the new grass seedlings by spreading a 1- to 2-inch layer of compost and tilling it into the top inch of soil. Rake out a smooth seed bed, removing rocks and other debris. After spreading grass seed, cover with a thin layer of straw mulch, and then avoid foot traffic until the first mowing.
Consistent watering makes all the difference.
Watering new grass seed is arguably the most important factor in speedy development. Beginning on the day you spread the seed, water daily with your irrigation system or a hose-end sprinkler until it has germinated. At this stage, your goal is to keep the soil surface moist. Do not water to the point of runoff or pooling or you may wash away the seeds before they have a chance to root. You may have to water two to four times daily for only a few minutes each time.
After the grass seeds germinate, your goal is to promote deep root development. Gradually decrease the frequency of watering and increase the duration. Here’s how that may look:
- Days 1 (seeding day) to 14 (germination observed): Water for 15 minutes four times each day.
- Days 15 to 21: Water 30 minutes one time each day.
- Days 22 to 28: Water 40 minutes one time on alternate days.
- Days 29 and beyond: Water 45 minutes three times per week, or enough to deliver 1.5 inches of water per week (skip watering when you receive sufficient rainfall).
Sprinkler systems, climate variables, soil types, and grass types all affect watering requirements. Contact your county’s Cooperative Extension Service for detailed guidance on lawn irrigation in your area.
Your beautiful new green lawn will be walkable and mowable when the grass is 4 inches high. Don’t mow too soon! Mowing before the grass is fully established slows root development and could ruin your hard work. Your lawn will continue to grow thicker as long as growing conditions are favorable.