Pre-Emergent Or Overseed? The Best Spring Solution For A Lush Lawn

Every homeowner dreams of having a beautiful, lush lawn that makes them the envy of the block. Now that spring has arrived, many are taking a hard look at their grass and deciding how they want to balance weeding with growing new grass. Laying down a pre-emergent herbicide to fight weeds will relieve you of pulling them, but there is a major tradeoff. 

So what is a pre-emergent herbicide? A pre-emergent herbicide aims to prevent weeds like crabgrass and ragweed from sprouting in your yard. Once applied, it forms a chemical barrier below the surface of the soil, which works to disrupt seed germination. Timing is everything here. You need to apply the herbicide early enough in the season to stop weeds from sprouting, but not so early that the chemical barrier wears off. This timing will vary by your location, but most experts recommend this treatment sometime between late February and April. If you opt for this approach, then that chemical barrier will also prevent grass seed from germinating.

Another method for growing a healthy lawn is overseeding. This involves laying down grass seed over an existing, yet thinning lawn, and is a great way to change your grass without removing it. Choose the patch you want to overseed and mow the existing grass short, and then aerate or rake the space if needed. This breaks up the soil so seeds can make better contact with it to germinate. Spread the seed evenly over the area, then fertilize and water it. Water two to four times a day, depending on your area, using a gentle spray so you don't knock the seeds out of the soil. Stay off that patch of your lawn, and in about two to three weeks, you'll see young shoots establish themselves. When the new grass reaches about 3 inches, then you can start mowing it.

Good news for gardeners: neither a pre-emergent or overseeding is inherently better or worse for your lawn. The difference between the two strategies comes down to your lawn, time, and money. If weeds regularly overrun your lawn, then a pre-emergent will give you some relief. You'll also spend less time this year pulling every dandelion that dares poke its head out of the soil, and you can hire a professional to lay down the herbicide if that fits your budget. This may also be a better option if your grass is already healthy and has few patches. 

Lawns that don't see too many weeds may not need a pre-emergent herbicide. In these cases, it might be easier to just weed as needed and focus on overseeding to revitalize thinning patches of grass. Overseeding is also a good option if you want to prioritize growing a lot of new grass without waiting until the herbicide wears off.

Depending on the timing, you can use these strategies one after the other. Pre-emergents last between 8 to 12 weeks. If you lay it down early enough, the herbicide will wear off around August or early September. Crabgrass specifically dies in the early fall, which makes it the best time of the year to reseed the lawn. The new seedlings will have a chance to establish themselves, and in the spring, they should help stop crabgrass and other weeds from germinating in the first place, thus eliminating the need for a pre-emergent herbicide at all.