Watering Grass Seed: Everything You Need to Know

Farmer sowing seeds in a green field

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While many gardeners are tempted to grow as many edible plants as they can, and others love to plant many perennial flowers, sometimes we're just doing our best to maintain a healthy lawn. A large lawn can surely be time-consuming and expensive in terms of care and upkeep, but small areas of lawn can be manageable and add a nice neutral area between flower beds and other landscaping features. Lawns are also great for kids and pets for playing and lounging, or a game of croquet, bocce or badminton.

Planting a lawn for the first time can be daunting. Most lawns contain plants other than grass, including invasive weeds that can take over (like ground ivy or crabgrass). But you can remove these weeds and add some new soil and plant grass seed to start over. Once you've selected your grass seed and prepared your soil, then plant your seed, the next and in many ways most important step is watering your grass seed. If freshly planted grass seed isn't watered properly, it won't germinate and you'll have to replant it.

The best time to plant grass seed is in mid spring, after danger of frost and before it gets too hot: this timing offers the best conditions for germination and growth. That said, you may find you have to plan later in the season for various reasons, such as construction of landscaping projects. Also it's not uncommon to overseed your lawn in the late summer or early autumn to fill in bare spots. In any case, proper watering will be key to successful growth.

Rain or Sprinkler?

In a perfect world, we'd get the adequate rainfall we need, and only on days when we don't have outdoor plans. But Mother Nature has Her own ideas, so we have to plan our watering schedule around the weather. If at all possible, plant your grass seed just before rain is due, but not harsh or heavy rainfall. It's also best not to plant just before a stretch of hot (above 80) sunny days, as this makes it harder for grass seeds to germinate.

Consistent, even but gentle watering is best for newly-planted grass seed. To sporadic and it may not germinate evenly, too heavy and it may get dislodged and wash away. An average rain shower is perfect. But in the absence of rain you can use a sprinkler to get a good even soaking on your new grass seed. Set it on medium and move it every twenty minutes or so, making sure all seeded areas are covered. Don't overwater. If you're "old school" and want to walk around with your hose, resist the urge to walk on the planted areas. If you have pets or kids, tying some tape or string with poles around the newly planted seed areas to keep them from trampling it is not a bad idea. Once the new shoots are two inches high you can remove the barrier.

Dark green rain barrel and hose by white porch on green lawn
Rain barrels come in many different sizes and designs and can help conserve water.  Inge Knudson / Flickr / CC BY 2.0

If you have a very large lawn, or find you are away a lot, you may consider investing in an irrigation system that can be programmed to use on a timer. Buying or building a rain barrel is also an environmentally-sound option and you can recoup your investment over time by saving on your water bill.

Check the Soil

If your seed is germinating slowly, maybe the soil needs a nutritional boost. Try sprinkling a mix of compost and peat moss lightly over the top of the seed area before watering. Composted manure, mushroom compost, used coffee grounds and wood ash are also suitable but be sure to mix them together well.

When to Water?

The best time to water your grass seed is early in the morning or after the sun has begun to go down. Night time is fine also. Watering when the sun is directly overhead is counterproductive and on a very hot bright day not only can be wasteful, as water evaporates faster in heat, but can actually be harmful. After a cool night, there may be plenty of dew on the grass in the morning, so watering later in the day offers a more consistent and regular amount of moisture for your lawn while also helping conserve water. Watering at night also draws earthworms to the surface (sign of a healthy lawn and garden!) so be careful walking.

Watering with Compost Tea

If your soil is less than optimal, this can make it harder to have a lush green lawn. One relatively simple solution to this problem, which is easier and less expensive than replacing your soil or adding lots of amendments, is to water with what is called compost tea. Other versions of this are manure tea or vermicompost tea. Essentially you're taking your compost and adding water, then straining it out with some fabric. You can put this in a watering can that had has the small-holed sprinkler/filter removed from the spout. You can also spread the moistened compost directly on your lawn. This nutrient-rich "tea" is a good addition for lawns that lack nitrogen and organic compounds.

Water Regularly!

You'll want to water your grass seed regularly for at least two weeks until it's established. Every other day is fine, but if it's very hot, every day is better. Watering in the evening ensures a longer period of moisture.