Is too much rain bad for grass seed? Typically, yes. Heavy rain often leads to soil erosion, which means the top layer of soil is worn down by water. If you seed right before a rainstorm, your fresh grass seed could get washed away through erosion.
New Grass Seed
Heavy rain can wash grass seed away. Keep seeds in place by covering it with peat moss, organic mulch or a biodegradable burlap. Covering your grass seed will also help conserve moisture and hide it from hungry birds.
The top inch of soil should stay moist at all times. This may take only 2-6 minutes, or longer, depending on your sprinkler system and the soil type. Use your best judgment, but moist, but not soggy is the plan!
Grass seed, when first planted has no roots or any way to stay attached to the ground or area it has been planted. This means, with too much rain, all that precious grass seed can easily be washed away!
Keep an Eye on the Weather
If it's sunny, 90 degrees and windy, you should be watering at least 3 times a day. Rain is a great way to get water on new grass seed but be careful! A light rain in the morning will dry out by the afternoon. Make sure the grass seed stays damp the entire day.
Dormant grass seeds can go without water for months. But once you plant and water the seed and it starts germinating, it can only last a day or two without water, depending on the soil type and the weather.
Overseeding can help you get back to the thick, lush, green lawn you're looking to achieve. By spreading grass seed over your existing lawn, you can thicken up the thin areas and get your lawn looking terrific again. (This is different from reseeding, which is when you start over and plant a completely new lawn.)
In conclusion, consistent watering is crucial for the growth and survival of grass seed. While newly planted seeds can survive for one day without water, it's best to maintain a regular watering schedule to ensure optimal germination and growth.
The answer not very cut and dry, but here is the bottom line: The vast majority of the time, rain after a fertilizer application is not a problem at all. In fact, it is usually a good thing. Keep in mind (I have said this before), your lawn needs about 1/2" of water after you fertilizer.
Standing water or prolonged heavy rain could ruin some of the seed or possibly wash the seed away. If overseeding a lawn where you have established grass, be sure to keep the seed moist by watering lightly twice a day. Occasional deep watering is okay to maintain grass health.
Very Small Patchy Areas: For tiny bare spots (think a few inches in diameter), throwing a small amount of seed and keeping the area moist might suffice. However, even in these cases, lightly raking the soil to create some seed-to-soil contact can significantly improve results.
What Happens If a Day of Watering Grass Seed Is Missed? Missing a day of watering in the critical germination phase can impact the health and growth of your new grass. If the soil dries out, it can halt the germination process or kill the young seedlings.
Don't overdo or cut corners. Too much grass seed causes undue competition for resources such as light, water and nutrients, and grass seedlings struggle as a result. Too little seed leaves lawns thin or bare.
Heavy rain can dislodge seeds (especially small ones, like lettuce), reduce the necessary air pockets in your soil for seed respiration, and promote fungal issues like damping off (which can prevent germination, kill germinant plants, and lead to low quality in the survivors).
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.
Some rain will help the grass to grow, but if your sod is subjected to heavy and sustained rainfall shortly after you've laid it, it may not be able to take root properly.
I'd try to throw a thin layer of peat moss or top soil/mulch on top. Thin as in . 25 in or less. I've had seed wash away from heavy rain.
One issue with heavy rains or floodwaters is that the water can wash away nutrients in the soil. If your grass is looking yellow or faded, you may need to add some fertilizer beyond what you normally use.
It's best not to overseed a wet lawn.
Eventually, they'll establish a schedule of soaking the lawn 2-3 times a week. Experienced lawn care providers monitor weather conditions and adapt watering schedules, skipping sessions after heavy rain.
The seed won't sprout without moisture, and if you water enough to break the seed coating but then let the seeds and seedling grass plants dry out, the young plants will die. Your goal is to apply enough water so that the soil surface stays damp at all times.
'There are several possible causes that may prevent the grass seed from growing, such as poor soil quality, inadequate sunlight or water, temperature extremes, bad seed, and pests,' says Susan Brandt, Co-Founder of Blooming Secrets.
Remember, lawn grass seeds only need to be lightly raked into the soil, or even just scattered directly on the soil surface. Any seeds buried more than the length of the seed will have a hard time germinating successfully.
While grass clippings themselves won't sprout new grass, they can play a significant role in supporting new grass growth and even contribute to natural reseeding under certain conditions.
Birds eat grass seed for a variety of reasons, but the most common reason is that it's easily accessible. When a freshly seeded lawn is left unprotected, it becomes an easy meal for birds of all sizes.