This Is Why Your Grass Seed Isn't Germinating
You bought that premium bag of fescue, then spread out the seed with your broadcast spreader exactly as specified by the instructions on the bag. You’ve been watering it three times a day religiously for three weeks and all you have is bare dirt to show for it. If your seed isn’t germinating, there’s a good chance the soil is the culprit.
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Soil Temperature That’s Too High or Too Low
This is perhaps the most common reason grass seed fails to germinate. Cool season grasses need soil temperatures to to be consistently above 50°F to germinate. Likewise, grass seed cannot germinate once soil temperatures exceed 75°F. Use a meat thermometer to check the soil temperature. If it’s not in the ideal 50°F-65°F, your seed won’t germinate.
Wrong Planting Depth
Grass seed must be planted at the proper depth or it may never germinate. Grass seed that’s sitting on the surface of the soil can dry out before it ever has the chance to awaken. Grass seed that’s planted too deep in the soil won’t receive the sunlight and oxygen it needs to germinate. Even if it does manage to spring forth from its seed shell, it may not have the strength to push through the ground. Grass seed should be planted at a depth of 1/4-inch to 1/2-inch to germinate properly.
High or Low Soil pH
Don’t waste time taking soil samples and sending it off to your local Ag extension or paying a service for an expensive soil testing service. Those solutions are too pricey and by the time the results come back, it will be too late to do anything about it. Purchase a rapid-test kit from your local home improvement store. These kits typically cost less than $20 and give you immediate results.
The soil test kit will tell you if your lawn is too acidic or too alkaline. Most cool season grasses, including Kentucky Bluegrass and fescues, need a pH of between 6.0 and 7.0 to germinate. If the pH is alkaline (too high), you'll need to add sulphur to your lawn to lower the pH back to neutral. If it’s too acidic, (high pH), you’ll need to add lime to bring the pH up.
Related: This is Why Those Bare Patches On Your Lawn Keep Coming Back
Soil Compaction
If soil pH isn’t the problem, the issue may be with soil compaction, which can cause a host of problems for your grass seed. Take a flathead screwdriver and attempt to drive it into the soil. If you can’t easily plunge the screwdriver 4 to 6 inches into the soil, you have a soil compaction problem.
When soil is too compact, it won’t allow oxygen to reach the seeds, essentially suffocating them. Even if the seed does germinate, its delicate roots won’t be strong enough to penetrate the dense soil. Instead of growing deep, the roots will grow shallow, which is a recipe for a very short life. Compacted soil also repels water, causing it to run off to the side, carrying your seed with it.
If your soil is compacted, you’ll need to loosen the soil to get grass seed to grow. You can aerate the soil, or solve your soil compaction issues and plant your seed in one fell swoop by renting a slit seeder. A slit seed cuts a slit into your soil and drops a seed into the hole, aerating and seeding your lawn simultaneously.
Poor Drainage
While you may be following the specified watering schedule to a tee, if the soil isn’t draining well, it could lead to problems. If the soil is too wet, the seed can rot. Inspect the soil. It should be damp but not soggy or waterlogged. When you water, there should be no puddling.