How do I care for a newly hydroseeded lawn?

A new hydroseeded lawn needs three things in its first few weeks: steady moisture, no traffic, and patience with weed control. After that, care shifts toward building deep roots before its first summer. Here is the routine in the order you will need it.

Weeks one to four: keep the seedbed moist

Water is the job that makes or breaks new seed. Virginia Tech's guidance is to irrigate lightly and frequently until germination and early establishment are complete.^[1] The goal is a damp surface, not a soaked one. Too much water can wash away or drown the seed,^[1] and puddles or runoff mean you have watered too long.

Newly seeded lawns need more frequent watering for the first three to four weeks^[2] than an established lawn. In practice:

• Water in short sessions, often in the morning and again in the afternoon when it is warm and sunny.
• Check by touch. The top of the mulch and soil should feel damp.
• Watch low or shady spots. They stay wet longer, and newly germinating seedlings are very susceptible to several soil-borne fungi that thrive in wet conditions.^[1] Water those areas less.
• Let rain count. Skip a session after a good soaking rain.

Keep people, pets and vehicles off the area. Soft soil takes footprints easily, and each one can bury or crush seedlings.

Leave the green mulch alone. Hydromulch does not need to be removed,^[6] and the grass grows up through it.

After the grass is up: water deeper, less often

Once the grass is up and filling in, gradually cut back on the amount of water to start promoting a deep root system.^[1] Move toward the pattern for established lawns, deep, infrequent watering that soaks the root zone to a 4-inch depth,^[2] instead of daily sprinkles that keep roots shallow.

Do not stop entirely. Lawns less than a year old have little to no drought tolerance,^[2] so a fall-seeded fescue lawn will still need water during dry spells the following summer.

The first mowing

Mow when the grass is tall enough to cut without scalping it. The rule is to never remove more than one-third of the leaf blade at a mowing.^[1] For tall fescue, Virginia Tech's example is to begin mowing when the new lawn reaches 3 inches.^[1] Wait for a day when the soil is dry enough that the mower leaves no ruts. The mower blade should be sharp and the soil surface firm,^[1] because a dull blade can tear young plants or pull them out instead of cutting them cleanly. Our guide on what height to mow fescue in Virginia covers the mowing height once the lawn is established.

Weeds: wait

New seedings usually show some weeds. Promoting fast establishment of the new grass helps you avoid most weed problems,^[1] so put your effort into watering and mowing and resist spraying early. Seedlings are much more sensitive to chemical applications than mature plants,^[1] and broadleaf weed killers usually cannot be applied until the new grass has been mowed at least twice.^[1] For annual bluegrass, there are no selective herbicides that can be used soon after seeding to control emerged annual bluegrass;^[1] a fast, dense stand is the defense.

Be careful with spring crabgrass control. Henrico County's Extension office notes that most crabgrass preventers also prevent turfgrass seed from germinating,^[4] so do not apply one where you have just seeded or still plan to patch. For later weed problems, see how to get rid of weeds without killing the grass.

Fertilizer through the first year

If the soil test was followed at seeding, the new lawn already has a starter dose. For cool-season grasses, the main feeding season in Virginia is fall, remembered as SON: September, October and November.^[1] Once the lawn is established, Virginia Tech's calendar allows up to 0.7 pound of water-soluble nitrogen per 1,000 square feet every three to four weeks^[3] during that period, and says to never apply fertilizer to frozen soil.^[1]

Skip summer feeding: cool-season grasses should not be fertilized from late May through July.^[5] On newly established areas, full establishment usually requires refertilization in the second growing season,^[5] guided by a soil test. Grass that looks yellow might be nitrogen deficient.^[5] More detail is in when to fertilize a lawn in Virginia.

Patch thin spots in the next fall window

Some unevenness is normal in a new seeding. Fill the gaps rather than letting weeds take them. Henrico County's SMART Lawns checklist lists overseeding between September 1 and October 15 as a lawn-care practice.^[4] Loosen the soil in thin areas first so the seed reaches it. If whole sections never came up, work through why hydroseed is not growing before reseeding.

Stop and call a pro if

• Runoff is cutting channels through the new seeding or carrying soil off the property.
• Large areas stay bare or die back after the first few weeks despite steady watering.
• Water pools near the foundation or the yard drains toward the house.
• You need the whole area re-prepared and resprayed. A contractor can redo it; see what hydroseeding costs in Virginia.

Browse more lawn and landscaping answers or see hydroseeding services. If you need help, describe the job once and local businesses quote it.