Grass seed can be planted in a weedy lawn. However, if the weeds are very thick, you will get better results if you deal with the weeds first. If there are just a few weeds, pull the largest ones, then apply the grass seed.
You may have a few weeds. It happens to everyone. Will grass seed still be able to thrive and grow amidst a few weeds?
Surprisingly, planting more grass is helpful to fend off the weeds! If those annoying weeds have less area to grow, they won’t spring up as fast. You asked, and I answered. Find out everything you need to know about weeds and grass seed!
Fall is a great time to overseed! The weeds should be dying down at this point. Check your local weather forecast for frost warnings. It is best to plant grass seed at least 45 days before the first frost. This will allow the new seed to take root before it goes dormant.
Author: Matt Hagens
Remove the weeds from the area by either manually pulling them out of the ground or applying weed killer to the area. Hand-pulling weeds is safer for the soil, but removing all the roots can be difficult. Chemical weed killer kills the weeds and their roots, but may damage grass seed and leave pesticide residue in the soil, if you plant the seeds too soon after the herbicide application. If you choose to use weed killer, wait 2 to 3 weeks before planting new grass seed.
Trying to grow grass in a weeded area is a frustrating task that generally provides undesirable results. Weeds are aggressive and invasive plants that choke out grass and flowers. They quickly take over an area and are notoriously hard to get rid of. When you choose to grow grass in an area overrun by weeds, you essentially have to start fresh by establishing new turf.
Till the top 6 inches of soil with a soil tiller. You can rent or purchase soil tillers at home improvement centers and rental yards. After the tiller turns under the dead weeds and soil, rake the soil with a garden rake to level the area as much as possible. Remove large rocks and break up clumps of soil.
Cover the soil with the correct grass seed for your location and the amount needed to cover the area. For example, some parts of the San Francisco Bay area work best with warm-season grasses — such as St. Augustine, buffalo or zoysia grass — while other Bay areas thrive with cool-season grasses such as tall fescue and perennial rye. Use your gloved hands to distribute the seeds evenly over areas smaller than 150 square feet. For larger areas, use a seed spreader.
Apply a thin layer – about 1/4 inch – of high-quality topsoil over the grass seed. Applying too thick and the seeds have a hard time germinating. Attach a garden hose sprayer with a mist option to a water hose. Dampen the top 6 inches of the soil with the water hose set on mist. Using a mist of water instead of a stream will prevent the seeds from washing away.
Read our handy guide on how to restore a weedy, patchy lawn to its former glory.
How soon you can plant seed depends on the type of weed treatment you choose. Pre-emergent herbicides will prevent grass seeds from growing just as much as weed seeds, so it would be no good to sow seeds immediately after.
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Then, it’s time to add starter fertilizer. Your best bet is to use a starter fertilizer high in phosphorus. However, due to concerns about water pollution, many states prohibit the use of phosphorus in fertilizers. Some states may allow phosphorus in fertilizers for establishing new lawns. If so, you’ll find fertilizers labeled “new lawn” or “starter fertilizer.”
Deep, infrequent watering can help establish your lawn by allowing it to grow deep roots, which can compete against weeds. Try to water your lawn about twice a week, in the morning before the heat of the day sets in. Lawns typically need about 1.5 inches of water per week, but that could vary based on the climate you live in and the type of grass seed you chose.
Always set the spreader to half the recommended drop rate and spread the seed in one direction, then one or two more in different directions to make sure the coverage is nice and even. You don’t want your lawn to have weird patterns or stripes.