Lawns

Early Spring Lawn Tips for Fertilizer and Pre-emergent Timing

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Speedwell is a winter annual weed. It will end its life cycle and die naturally once we have consistently warm temperatures. Photo: G. Rinehart

The warmer-than-normal weather during February had many people thinking about an early start to lawn and garden season. However, as temperatures have dropped and been below normal for much of March, it looks like we may have a couple more weeks before lawns really start growing. Lawn growth and crabgrass emergence are related to soil temperature, which is slower to change than the air temperature. While I have heard reports of soil temperatures topping out in the mid-50s for a day or two, it’s important to remember that in order to germinate crabgrass needs soil temperatures around 53-55⁰ F sustained for 5 days. These two things lead to a few questions, particularly pertinent this year when February felt like March and now March feels like late February.

Should I fertilize my lawn now?

While the legal window for applying fertilizer to lawns in Maryland began on March 1, that doesn’t necessarily mean you should fertilize your lawn just yet. Unless the grass is actively growing (which is dependent on warmer soil temperatures) it likely won’t take up and use the fertilizer—so you are better off waiting until the lawn is actively growing. Temperatures consistently around 60 and enough growth to warrant a second mowing are pretty good indicators of this. Keep in mind that if you fertilized your lawn in the fall you can probably wait until after the “flush of growth” in the spring (usually April/early May) and then schedule your spring fertilizer application for after that “flush” and leading into summer—usually around mid-late May. If you didn’t fertilize last fall it is tempting to try to “jump-start” the lawn in early spring with a fertilizer application, but hold off until the soil temperatures are consistently warmer and highs are around 58-60⁰ F on a regular basis.

Should I apply crabgrass pre-emergent now?

I would wait until soil temperatures are 53-55⁰ F sustained for 5 days. Keep in mind that your best defense against crabgrass is a dense turf that crowds out crabgrass seedlings. So, if you have good turf density and mow at 3” or higher, your overall crabgrass pressure should be lower anyway. The typical recommendation is to wait until the forsythia is “half green-half gold” (or even a little earlier), but with the warm February we had, that indicator may or may not be as accurate this year. You can check soil temperatures for your location at the following website: https://www.greencastonline.com/tools/soil-temperature. 

Is there harm in applying crabgrass pre-emergent too early?

Probably not, unless it’s applied several weeks early and the product starts to break down before crabgrass even starts germinating. If you want to maximize the period of time your crabgrass application is effective, wait until when conditions are conducive to crabgrass germination and then apply it.

grassy lawn weed called roughstalk bluegrass
Roughstalk bluegrass (Poa trivialis) is a cool-season weed that shows up in early spring. If you only have a few patches, you can dig them out by hand (including the roots) and overseed to fill in the bare spots. Photo: G. Rinehart

On another note, this is now the time of year when many winter weeds become more noticeable as they are likely producing flowers and setting seeds. While you can apply selective products to control these weeds, remember that these winter annuals like chickweed, purple deadnettle, speedwell, henbit, etc. are almost at the end of their lives and will die naturally once we have consistently warm temperatures. Another weed often noticed this time of year is the grassy weed called roughstalk bluegrass (Poa trivialis). Seeds of this grass are often a contaminant in turfgrass seed mixes (the cheaper the seed, the more likely you will have weed seeds) and this grass starts growing much earlier than tall fescue. As the temperatures warm, it is not as aggressive and noticeable. There are few selective control products that are labeled for roughstalk bluegrass and they tend to be restricted to professional sites and/or are expensive. If you only have a few patches in your lawn, digging these out (including the roots) and then re-seeding the spot with a soil-tall fescue mix is the best control approach for most homeowners.

By Geoffrey Rinehart, Lecturer, Turfgrass Management, Institute of Applied Agriculture, University of Maryland. Read more articles by Geoff.

The Time to Spring Seed Your Lawn is Now

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With springtime springing, many people are thinking about planting in their yards and gardens. While the best time of year to plant grass seed and renovate is in the fall, we have a narrow window in the spring that can be taken advantage of to try to fill in bare spots and thin areas. Thin or weak areas that may have been damaged over the winter or even last summer are very prone to crabgrass and other weed invasion as we get farther into spring and early summer. With cooler weather forecast later this week (many areas are predicted to have frost in the morning), we still have a good window over the next two weeks for spring grass planting. If you have already applied crabgrass preventer, then you’ll have to wait until fall to plant grass seed, but if you haven’t, now is a good time to try to “thicken up” some weak spots and create more density before weeds have a chance to get a foothold. 

While a “full scale” lawn renovation should only be done in the fall (unless you are using all sod), spring is a good time to rejuvenate thin or weak areas. To do this, use a hard metal rake to remove any dead plant debris from the area and expose the soil. Use a drop spreader or handheld spreader (larger area) or sprinkle seed by hand (smaller area) as you try to get good, even coverage of the area (for tall fescue seed you will want to have about 6-10 seeds/square inch seed density). You can then very lightly rake the area to get the seed worked into the soil less than 1/2″ or carefully step on seeds to ensure good seed-to-soil contact. Next, be sure to cover the seed by topdressing compost or peat moss over the newly seeded area. This will help the seed retain moisture until it starts to germinate and provide some protection from birds. Lastly, try to keep the new seed damp at least until germination. With our cooler weather and a few showers in the forecast, the upcoming weather will help with keeping the seeds moist until they germinate but you may have to do a little watering with your garden hose or sprinkler too. 

We don’t have a big window of time for spring seeding, but seeding now before crabgrass and other weeds become more active later in spring will help increase the density of the lawn and make it better able to resist weed invasion!

By Geoffrey Rinehart, University of Maryland Institute of Applied Agriculture

Lawn and Garden Tips for April

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Wildlife

Eastern box turtle
Eastern box turtle

  • Eastern box turtles and various species of snakes are coming out of hibernation and may visit your yard. Box turtles are becoming scarce throughout much of Maryland because of road mortality and habitat destruction. Observe turtles, but don’t collect them as pets.
  • The eggs of amphibians like wood frogs and toads will hatch in a couple of weeks and produce many small tadpoles. If you need to do some work in your pond, try not to disturb their eggs. Learn more about Creating a Herp Friendly Landscape and Interesting Visitors in Your Landscape.

Houseplants

(Cissus rhombifolia) Oak or grape leaf ivy
(Cissus rhombifolia) Oak or grape leaf ivy

  • This is a good time to re-pot and divide houseplants. Use lightweight, well-drained soilless potting mixes containing peat moss, vermiculite, and perlite.
  • Begin to fertilize houseplants again. The increase in natural light will prompt them to grow.
  • Fungus gnats are small, harmless black flies that hover around, breed in and feed on moist growing media. They can be controlled by being careful not to over-water houseplants. Growing media should be allowed to dry out before watering again.

Lawns

  • LawnThe height and frequency of mowing lawn are very important. Cool season grasses such as tall fescue and bluegrass should be maintained at 3.0 inches for most of the growing season.
  • Keep your mower blades sharp to prevent turf damage. Dry, white, or tan-colored grass blade tips are an indication that the mower blade is dull. Dull mower blades tear turf grass and can lead to disease problems.
  • Leave the grass clippings where they lay. “Grasscycling” eliminates bagging labor and adds organic matter and nitrogen to your soil, allowing you to apply 25% less nitrogen fertilizer.

More tips from the Home & Garden Information Center

The Home & Garden Information Center’s horticulturists are available year-round to answer your plant and pest questions. In addition to gardening questions, we cover houseplants, indoor pests, and more. Send your questions and photos to Ask an Expert!

Lawn and Garden Tips and Tricks for November

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Lawns

  • Typically, November is too late to broadcast lawn seed and expect it to survive the winter. Consider waiting until early spring.
  • This is still a good time to control wild garlic, clover, ground ivy, chickweed, and other difficult weeds with an herbicide if daytime temperatures remain in the sixties. Do not spray herbicides around ponds or on breezy days. Always read and closely follow all label instructions.
  • According to Maryland’s Lawn Fertilizer Law (PDF), the last application of fall fertilizer needs to be applied before November 15th.
  • Lawn info on HGIC

Continue reading →

Lawn and Garden Tips and Tricks for August

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For Ornamental Plants:

  • Late August through September is usually a good time to transplant, divide and plant perennials such as daylily, liriope (photo left), and echinacea.  Be sure to keep them well watered during dry periods.
  • Annuals and perennials, like yarrow and salvia, may have grown spindly and are not flowering well. Cut them back to encourage re-bloom. Deadhead the spent blooms of annuals like zinnias and marigolds. This will encourage them to continue blooming more vigorously.
  • Plant hardy mums for fall color this month so they will become well established prior to the winter.

More August ornamental tips

For Lawns:

  • In dry periods grasses go dormant but recover when rain returns. Newly seeded or sodded lawns may actually be dead and will need to be reseeded.
  • Mid-August through mid-October is the best time to start new lawns and renovate or overseed existing lawns. We recommend a turf-type tall fescue cultivar at a rate of 4 lbs. of seed per 1,000 sq. ft. of area for overseeding, or 8 lbs. per 1000 sq. ft. for new lawns.
  • If your lawn area contains more than 50% weeds, consider a total lawn renovation. Newly seeded turf must be watered regularly. See Starting a New Lawn.

More August lawn tips

Outdoor Insects:

  • You may notice the European hornet stripping the bark off shrubs (especially lilac) and trees. This stripping of the bark is usually minor and does no real harm to a shrub or tree. The European hornet is a large yellow and brown hornet (photo) that nests in cavities in trees, stumps, wood piles, sheds, etc. and feeds on insects. Unlike most other wasps and hornets this one is a night flyer.
  • Do not spray pesticides in your garden unless you’ve observed a particularly serious pest and the damage caused by the pest. Follow all label directions. Always select the shortest residual, least toxic insecticide to avoid killing beneficial insects.
  • Avoid mosquito and midge problems by turning over any pots, lids or saucers that might collect water and create a breeding site. Also check clogged house gutters another favorite breeding place for mosquitoes and midges. Many people use corrugated drain pipe attached to downspouts to help move water away from their homes. The corrugations hold water and are a prime place for tiger mosquitoes to breed. To avoid the problem, use a smooth drain pipe or securely attach the corrugated drain pipe to the downspout and cover the open end with a piece of pantyhose secured with a rubber band. This will keep adult female mosquitoes and midges out of the drain pipe.

More August indoor and outdoor insect tips