The Time to Spring Seed Your Lawn is Now

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

Summer Lawn Woes: Reasons Why Tall Fescue Grass Declines at This Time of Year

It seems like a while ago, but it was only 5 weeks ago that we were experiencing a fairly gentle start to summer. We even had a few days in June with highs in the 60’s and it made for pretty easy lawn growing weather.

Flip the calendar to mid-July and it has been a different story. All of us knew summer would arrive eventually, and now we are dealing with high temperature and high humidity conditions very typical of mid-summer in Maryland.

For those with warm-season grass lawns, like zoysiagrass, the lawn should be thriving, as these grasses enjoy the heat. For most homeowners who have tall fescue, summer is always a challenge to minimize the heat stress and disease pressure on the lawn. Tall fescue is best adapted to growth when low temperatures are in the 50’s and highs are in the 70’s to around 80. Through July, we have had many days near or above 90 and many nights where the temperature didn’t drop below 70.

drought stress symptoms on tall fescue lawn
Drought stress symptoms appearing in tall fescue lawn. Drought-stressed plants exhibit a purple to grayish hue. Photo: Geoff Rinehart

There are a few different reasons your tall fescue lawn may be going brown or declining this time of year—the most common are related to drought stress, soils that are too wet, or brown patch disease. Typically, growth slows down a bit in mid-summer anyway as part of a grass’s natural growth cycle as it uses more carbohydrates (food reserves) than it makes. So when the grass does experience stress or disease it is slower to recover. Drought-stressed plants exhibit a purple to grayish hue, a narrower or “curled up” leaf blade, and footprints are visible for several minutes after walking across a drought-stressed area. Continue reading

Q&A: Tire Gouges in a Lawn and Planting Grass After Construction Work

lawn with tire gouges
University of Maryland Lecturer and Turfgrass Management Advisor Geoff Rinehart answers your questions about lawn care and planting. For more Maryland lawn care information, see the University of Maryland Extension Home & Garden Information Center website.

Q: I had a new shed put on my property. The delivery driver had to back onto my lawn. The weight of the truck and the flatbed put an initial 2-3 inch depression in the lawn. Where the driver had to pivot the trailer, the flatbed tires dug into the lawn 3-4 inches. In order to recover the contour of the lawn and deal with the gouges, what steps do you suggest I take? Today, after it rained all day, I went out on the lawn and attempted to press the humps down with my body weight and somewhat level the lawn back. I am worried, though, that the depressions indicate a serious compaction of the soil and damage to further propagation of the lawn.

Answer: You are correct – the gouges made by the flatbed have likely caused serious compaction to the area. You can try to press the gouges back into place and aerify now and topdress with ½” topsoil to try to smooth things out and see what happens next year. If you notice the area is struggling compared to the rest of the lawn and drying out more quickly if we have a dry summer, you’ll probably want to renovate the affected area by rototilling, re-grading, and re-seeding.   Continue reading

Q&A: Japanese Stiltgrass Management and Lawn Fertilization Tips

University of Maryland Lecturer and Turfgrass Management Advisor Geoff Rinehart answers your questions about lawn weeds and fall fertilization.

Q: What is this “grass” and is it possible to eradicate it from our lawn? It has been spreading down the hill from our neighbor’s property. What’s the best way to bring our lawn back to a nice quality grass?

Japanese stiltgrass in a lawn

Answer: Japanese stiltgrass (Microstegium vimineum) is an invasive summer annual grass that is becoming more pervasive in Maryland. While it used to be more limited to just woodland areas, we are getting more reports of it infesting lawn areas in recent summers.

As is the approach with any weeds, practicing good turfgrass cultural practices to encourage a healthy, dense stand of grass is the cornerstone of any lawn management program. Mowing taller (3”-3 ½”), fertilizing based on University of Maryland recommendations, and overseeding annually with improved turfgrass cultivars are three practices that will help create greater density.

This summer has been a particularly difficult one for controlling summer annual grasses like crabgrass, goosegrass, and, of course, Japanese stiltgrass since these weedy grasses are favored by wet, hot conditions like the weather we had in July-September. Since Japanese stiltgrass is a summer annual, it can be deterred by applying a pre-emergent herbicide in the spring at forsythia bloom (which is a similar approach to crabgrass control). When watered-in, pre-emergent herbicides form a soil barrier to seed germination. However, most of these products only last 6-10 weeks (the lower part of this range when it is wet and/or hot, the upper part when it is dry and/or cool). This May was rather rainy, so if you applied a pre-emergent in early April, another should have been applied in June. Usually, two applications are enough to get us to early August and then summer annual weed pressure decreases as early cooler weather is usually a month around the corner.  Continue reading

A Lawn Retrospective on the Summer of 2018: Looking Ahead to the Fall Season

nutsedge and crabgrass in a lawn
Nutsedge and crabgrass have been particular challenges this year with all of the late summer rain.

It seems like ages ago, but during late spring and early summer we were in the midst of a long dry spell–and then things changed! It seems once the rain started it hardly ever stopped during late July and early August and all of this rain created its own set of problems. In particular, summer annual weeds and sedges were given new life with all of the wet conditions. For many homeowners, it has been a difficult summer keeping weeds like crabgrass, Japanese stiltgrass, kyllinga, and nutsedge at bay during the wet, humid weather. Even folks who had applied a second application of pre-emergent herbicide in late spring were seeing that product break down more rapidly with the inordinate amounts of rain the region experienced.

University of Maryland (UMD) research (and others) has indicated that the best way to deter crabgrass is to mow higher. Experiment plots mowed in the 3½-4” range have consistently had less crabgrass invasion than plots mowed at 2” or 3”. While this late summer weather has led to a lot of crabgrass and sedge invasion, homeowners can take solace in the fact that relief is in sight as far as the calendar is concerned. Late August/early September is the perfect time of year to re-seed with cool-season grasses like tall fescue to undertake a full-scale renovation or a lawn “rejuvenation.” Continue reading

Lawn Tips for Summer: Don’t Overmanage!

lawn mowing height
Mowing at 3-3 ½” will reduce the potential for summer weeds. Photo by Geoff Rinehart

With summer right around the corner and gardening season in full bloom, many homeowners have been spending more time outdoors with yard maintenance activities. One temptation is to “want to do something’’ to make your lawn better since it has been a long, cool spring and it has only been in the last few months or so that things have really started growing. However, it’s important to remember that “doing something” for the sake of just “doing something” can have negative consequences, especially as we enter the hot months of summer.

Continue reading

Spring Lawn Care: How to Deal with Weeds and Bare Spots

forsythia shrub in bloomWith spring gardening season right around the corner, lawn questions have been rolling into the Home & Garden Information Center (HGIC). Here I’ll address some of the most common questions about weeds and overseeding.

Dealing with Winter Weeds

chickweed
Chickweed

In late winter/early spring, we typically see winter annual weeds in thin, under-fertilized, wet, or shady areas. These weeds germinated in the fall and will die as the weather warms up later in the spring. In my observations, this has not been a particularly bad year for winter annuals. They are favored by wet, mild winters and I think we had just enough “bitter cold” in January and a fairly dry stretch through December and January to reduce populations.

Typical winter annual weeds include chickweed, henbit, purple deadnettle, and shepherd’s purse. Options to address these winter annual weeds include hand pulling, spot spraying with a broadleaf herbicide, or waiting until they die once weather climbs to the 60’s and 70’s on a regular basis. For perennial weeds like dandelion which will start to re-emerge later this month, hand-pulling or spot spraying are the best methods for control.

Continue reading