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
