How long should grass seed take to sprout?

Perennial ryegrass 5 to 7 days, tall fescue 7 to 12, bermuda 7 to 14, Kentucky bluegrass 14 to 21. Most bags are a blend, so germination arrives in waves rather than all at once.

Will grass seed germinate if it dries out?

Not once it has absorbed water and started the process. A seed that swells and then dries is dead, which is why one missed watering on a hot afternoon can cost the whole seeding.

Can grass seed be planted too deep?

Yes. Seed needs light contact with soil, not burial, about a quarter inch at most. Raking it in hard or covering it with topsoil puts it deeper than the seedling can climb out of.

How long before I give up and reseed?

Wait three weeks past the slowest species in your mix. Bluegrass is still coming up at day 21, and reseeding on top of viable seed wastes both bags.

Why Is My New Grass Seed Not Germinating?

Two causes account for most failed seedings. The soil was the wrong temperature, or the surface dried out once after the seed had taken up water. Everything else on this list is comparatively rare.

First, check you have actually waited long enough

Grass	Days to germinate
Perennial ryegrass	5–7
Tall fescue	7–12
Bermuda	7–14
Kentucky bluegrass	14–21

Most bags are a blend. The ryegrass comes up first and makes the lawn look patchy and disappointing while the bluegrass is still working, so plenty of people reseed at day 10 on top of seed that was about to germinate.

Give it three weeks past the slowest species in the mix before calling it.

Cause 1: soil temperature

Seed responds to soil, not air. Cool-season grasses need soil consistently above about 50°F. Bermuda wants 65°F or more. A warm week in March does not warm soil, and a cold snap after sowing stalls everything that was underway.

A soil thermometer at 2 inches settles this in ten seconds, and it is the same measurement that drives pre-emergent timing and spring fertilizing.

If you seeded late in autumn, the answer may simply be that it is too cold now and germination will happen in spring. That is covered in when it is too late to plant grass seed.

Cause 2: it dried out

This is the big one. A seed absorbs water and begins to germinate. If the surface dries before the root establishes, it dies. There is no recovery, and no visible warning that it happened.

New seed needs the top half-inch damp continuously, which means light watering two or three times a day rather than one deep soak. The full schedule is in how often to water new grass seed.

Cause 3: no seed-to-soil contact

Seed lying on top of thatch germinates into a dry layer that never holds moisture, and it dies there. Seed sitting on hard, unprepared soil washes into low spots at the first watering.

Before seeding, mow low and bag, then rake or core aerate so seed can actually reach dirt. If your lawn has a spongy layer, measure it first: when to dethatch.

Cause 4: buried too deep

Grass seed needs light and a quarter-inch of cover at most. Raking it in aggressively, or spreading topsoil over the top, buries it beyond what a seedling can push through. Press it in with a roller or by walking it if you want better contact. Do not cover it.

Cause 5: pre-emergent is still active

Crabgrass preventer does not distinguish between weed seed and grass seed. If any went down in the previous 8 to 12 weeks, nothing you sow will germinate and the seed is simply wasted. This catches people out every spring: why those two jobs conflict.

Cause 6: the seed itself

Check the test date on the bag. Seed loses viability with age, and bargain contractor mixes are cheap partly because of low germination percentages and high weed seed content. Look for a recent test date and weed seed under 0.5%.

Birds take some seed, though rarely enough to cause total failure. If nothing at all came up, look at the other five causes first.

What to do next

Work out which cause you hit before reseeding, or you will repeat it. That is the entire point of the exercise.

If the bare patch you were fixing has now failed twice in the same place, the seed was never the issue. Something about the site is defeating it, and why the same patch thins out every year covers what to dig up and look at before you buy a third bag.