Lawn help - Ask Extension
Last fall we were able to aerated our lawn but we're not able to dethatch and oversees. My question is, where do we start this spring? Seed? Weed and ...
Knowledgebase
Lawn help #894410
Asked March 14, 2025, 12:00 PM EDT
Last fall we were able to aerated our lawn but we're not able to dethatch and oversees. My question is, where do we start this spring? Seed? Weed and feed?
Howard County Maryland
Expert Response
We received a similar question from you (with photos) on March 7, which we responded to. We can copy the information below in case you didn't receive that reply:
We could use more information to help answer your questions. What kind of lawn do you have, cool-season (tall fescue, mainly) or warm-season (zoysia, usually)? While sometimes we'd be able to tell given how brown the grass looks in the photos, which is what zoysia would look like this time of year, this winter has caused even fescue lawns to turn more brown than usual during dormancy, so it's harder to tell them apart. Zoysia requires different care than fescue. For instance, zoysia needs regular dethatching, while fescue does not because it barely forms a thatch layer. Fescue should ideally be overseeded annually in early autumn, while zoysia tends not to be overseeded at all (because it's rarely sold as seed, and zoysia seed is harder to grow than fescue seed), and instead is plugged or sodded in late spring or early summer (May-June) if lawn repair is needed.
Weed-and-feed products are not recommended, in part because they don't allow for customization in applying the right type of fertilizer at the ideal time of year for the grass (which will depend on turf type), as well as the proper timing for the herbicide application (which will also depend on the weed(s) in question). Lawn fertilizer in Maryland cannot contain phosphorus (the P in the N-P-K nutrient analysis) if a laboratory soil test doesn't show a P deficiency. Now is a good time to submit soil samples for testing if you haven't had the lawn tested in the past 3 years. Do you know what particular weeds you're trying to prevent? Which species are a problem will dictate what herbicide (if any) is the most effective, and when it's applied. If you don't know which weeds are present, you can use the linked page to compare them, and send us photos for ID once they resume growth.
If you want to even-out a lawn, which will help avoid scalping it with a mower, you may need to renovate it (or the uneven portion of it). Information about renovation steps are included in the page linked above about overseeding. Moles and voles tend to be temporary issues since the animals don't live that long, or they move on to new habitat once they're run out of resources. Plenty of wild predators eat them, like hawks, owls, foxes, and snakes, so the problem often resolves itself. If management is needed, you'd probably need to use lethal traps to reduce the population; we do not recommend the use of any type of poison bait, which can harm predators and other wildlife. The resources below provide more information on mole/vole control:
We could use more information to help answer your questions. What kind of lawn do you have, cool-season (tall fescue, mainly) or warm-season (zoysia, usually)? While sometimes we'd be able to tell given how brown the grass looks in the photos, which is what zoysia would look like this time of year, this winter has caused even fescue lawns to turn more brown than usual during dormancy, so it's harder to tell them apart. Zoysia requires different care than fescue. For instance, zoysia needs regular dethatching, while fescue does not because it barely forms a thatch layer. Fescue should ideally be overseeded annually in early autumn, while zoysia tends not to be overseeded at all (because it's rarely sold as seed, and zoysia seed is harder to grow than fescue seed), and instead is plugged or sodded in late spring or early summer (May-June) if lawn repair is needed.
Weed-and-feed products are not recommended, in part because they don't allow for customization in applying the right type of fertilizer at the ideal time of year for the grass (which will depend on turf type), as well as the proper timing for the herbicide application (which will also depend on the weed(s) in question). Lawn fertilizer in Maryland cannot contain phosphorus (the P in the N-P-K nutrient analysis) if a laboratory soil test doesn't show a P deficiency. Now is a good time to submit soil samples for testing if you haven't had the lawn tested in the past 3 years. Do you know what particular weeds you're trying to prevent? Which species are a problem will dictate what herbicide (if any) is the most effective, and when it's applied. If you don't know which weeds are present, you can use the linked page to compare them, and send us photos for ID once they resume growth.
If you want to even-out a lawn, which will help avoid scalping it with a mower, you may need to renovate it (or the uneven portion of it). Information about renovation steps are included in the page linked above about overseeding. Moles and voles tend to be temporary issues since the animals don't live that long, or they move on to new habitat once they're run out of resources. Plenty of wild predators eat them, like hawks, owls, foxes, and snakes, so the problem often resolves itself. If management is needed, you'd probably need to use lethal traps to reduce the population; we do not recommend the use of any type of poison bait, which can harm predators and other wildlife. The resources below provide more information on mole/vole control:
- Effective Mole Control -- Ohio State Extension
- Moles -- Penn State Extension
- Controlling Voles -- Virginia Tech
My question number is 0164326. You have several questions that I need to answer. We have cool-season, tall rescue grass. According to a plant identified app, we have common blue violet, common plantain, and common cchickened. I really appreciate your help.
Thank you for the additional information. Fortunately, if the lawn is predominantly or entirely tall fescue, you probably don't need to do any dethatching. (If for some reason it has lots of thatch, late summer or early autumn would be a good time to dethatch it.)
As a perennial, violets can be harder to manage without herbicide, since removal of their top growth won't keep the roots from regrowing new foliage, and they won't end their life cycle this summer like the winter annuals will. However, violets are largely native (including the type you mentioned), and they provide food for several pollinators and the caterpillars of a few local butterflies (in the fritillary group). If you are amenable to leaving them, we recommend letting them mingle with the lawn. Otherwise, they will need to be dug out or spot-treated with a systemic herbicide, possibly more than once. (Always follow herbicide label directions for use, as they can vary from one product to another.)
Plantain will require a similar approach as the violets -- digging up or herbicide treatment. Although those in lawns are not native, they can support one or two species of caterpillar as well. Use of a more organic herbicide, like some products using iron as their active ingredient, might be sufficient to weaken the plant, since that ingredient tends to have a greater impact on broadleaf weeds compared to grasses.
Common Chickweed is a winter annual and will die out on its own in about two months or less. Winter annuals germinate in late summer or autumn, overwinter, and then bloom and go to seed in spring as they die out. Therefore, you don't need to do anything now, but if you felt the need to intervene, you can treat them with a contact broadleaf herbicide (a systemic is overkill) that is labeled for use in turfgrass (so it won't damage the grass in the process). The main focus for winter annual weed control is discouraging seed germination next autumn. This can be done chemically with pre-emergent herbicides, but it's best to avoid herbicides where possible. Instead, focus on making the lawn more dense and vigorous so it out-competes most weeds on its own in the future. The overseeding you want to do is one main way to achieve that, and you can look for recommended cultivars of turfgrass (sometimes it's hard to find more than one at a time) to sow around next September.
Even though we don't recommend its use regardless, a weed-and-feed product won't be useful if applied this spring for any of the three weeds you mentioned. More useful steps to take include soil testing (if it's been about three years or more since your last test, if any has been done), making sure you're mowing the lawn high (cutting too short encourages more weeds; aim for a 3 to 4-inch mowing height for tall fescue), and consider fertilizing (after the soil test results come back) if the lawn looks a bit anemic or weak. (If it looks lush, you can wait to fertilize in late summer or early autumn.)
Miri
As a perennial, violets can be harder to manage without herbicide, since removal of their top growth won't keep the roots from regrowing new foliage, and they won't end their life cycle this summer like the winter annuals will. However, violets are largely native (including the type you mentioned), and they provide food for several pollinators and the caterpillars of a few local butterflies (in the fritillary group). If you are amenable to leaving them, we recommend letting them mingle with the lawn. Otherwise, they will need to be dug out or spot-treated with a systemic herbicide, possibly more than once. (Always follow herbicide label directions for use, as they can vary from one product to another.)
Plantain will require a similar approach as the violets -- digging up or herbicide treatment. Although those in lawns are not native, they can support one or two species of caterpillar as well. Use of a more organic herbicide, like some products using iron as their active ingredient, might be sufficient to weaken the plant, since that ingredient tends to have a greater impact on broadleaf weeds compared to grasses.
Common Chickweed is a winter annual and will die out on its own in about two months or less. Winter annuals germinate in late summer or autumn, overwinter, and then bloom and go to seed in spring as they die out. Therefore, you don't need to do anything now, but if you felt the need to intervene, you can treat them with a contact broadleaf herbicide (a systemic is overkill) that is labeled for use in turfgrass (so it won't damage the grass in the process). The main focus for winter annual weed control is discouraging seed germination next autumn. This can be done chemically with pre-emergent herbicides, but it's best to avoid herbicides where possible. Instead, focus on making the lawn more dense and vigorous so it out-competes most weeds on its own in the future. The overseeding you want to do is one main way to achieve that, and you can look for recommended cultivars of turfgrass (sometimes it's hard to find more than one at a time) to sow around next September.
Even though we don't recommend its use regardless, a weed-and-feed product won't be useful if applied this spring for any of the three weeds you mentioned. More useful steps to take include soil testing (if it's been about three years or more since your last test, if any has been done), making sure you're mowing the lawn high (cutting too short encourages more weeds; aim for a 3 to 4-inch mowing height for tall fescue), and consider fertilizing (after the soil test results come back) if the lawn looks a bit anemic or weak. (If it looks lush, you can wait to fertilize in late summer or early autumn.)
Miri
