Spring arrives none too soon for most new Englanders, and anticipation for the arrival of warm weather and the green growth it heralds inspires us to get out in our lawns and gardens. Some winters are almost unbearably long- snowy and cold- but at last the snow will melt. Once more we anticipate a welcome green-up as the weather eventually warms up. In early spring lawns may look a dismal brown after sitting under snow cover during the winter. The question is, will the grass be all right, or is there a reason for concern?
Salt damage to lawns can be an issue year after year where deicing salts are used along roads and sidewalks. Kentucky Bluegrass and perennial ryegrasses are more prone to salt damage than fine-leaved fescues and turf- type tall fescues. If salts are not flushed past the root zone, especially as snow melts or rains come in the spring, grasses may be killed and reseeding may be necessary. Before seeding areas where salt has killed the grass, make sure to flush the salts from the soil or else grass seed may not germinate well and seedlings may be injured by absorbing any salts that remain in the soil. Consider planting fescues where salt damage is a chronic problem.
Vole activity under snow cover can cause damage to lawns as well. These mouse- sized rodents are active all year and are safely hidden from predators during the winter if there is snow that covers the ground. Grass can be killed if voles feed on the crowns of the plants, and runways where they travel can be worn down to the soil surface. Rake up any dead grass and seed these areas as well as runways worn down to the soil. See the fact sheet Mice, Voles, and Moles.
As soil temperatures climb above 50 degrees, grass will begin to show signs of life. Sunny areas will be the first to green up while areas having some shade may lag behind. Certain grasses, such as Kentucky Bluegrass, are slower to green up in the spring, while perennial ryegrasses are quicker, both in green- up and regrowth. If the lawn does not respond to extended periods of warmer weather and some spring rain, it may be due to snow molds that attacked it under snow cover, or it may be dead. Snow molds are fungal diseases that infect grasses under snow cover or during cool, wet winters where grass was fertilized in late fall with a fast release nitrogen fertilizer. They can be severe where snow has been piled up along sidewalks or driveways providing the insulation needed for the fungus to grow. Snow melt reveals areas where turf was subjected to the disease. Pink snow mold may kill grass, and can be identified by tan patches having a pinkish border. Gray snow mold will not have pink borders and close inspection will show small dark fruiting bodies on leaves and stems. Gray snow mold is not usually fatal. Rake up these areas to remove dead leaves, and the grass should recover. Areas affected by pink snow mold may need to be raked up and seeded.
It is tempting to want to fertilize as soon as lawns start to appear green, but wait until the grass actually is growing, especially if a fast- release nitrogen source is used. This is because grass roots have been storing carbohydrates since last fall, and are using them to produce growth in early spring. As these carbohydrate reserves are depleted when growth resumes in the spring, an application of fertilizer is of better use to the plant when it has actually used up some of its own resources. If an organic fertilizer is used, wait for the soil surface temperatures to consistently remain above 50º, as the microbes in the soil that break down the fertilizer are more active as soils warm up.
If areas of the lawn are thin and seeding is considered, there is a tendency to want to rush out and do something before soils are warm enough to provide good seed germination. The grasses we use for lawns in New England are cool season grasses, and soil temperatures above 50º for the seed to germinate. Usually soil temperature lags a little behind air temperatures, but catch up quickly. If crabgrass has been a problem where spring seeding will be done, there are two pre-emergent herbicides available for homeowners that will prevent crabgrass from invading from seed while allowing the desirable grass seed to germinate and develop. The herbicides are Tupersan™, with the active ingredient siduron, and Tenacity™, with the active ingredient mesotrione. Tenacity can also be safely applied at the time of seeding to control broadleaf weeds of over 40 species. Use these products as directed on the labels.
Spring seeding can have mixed results. Grasses need time to establish a good root system and hot weather usually arrives before this can happen. If hot, dry conditions occur newly seeded areas may need a deep watering once a week. If supplemental irrigation is not used grass will go dormant and may die if the roots are shallow.
Pre- emergent crabgrass control can be considered for chronic problem areas. Note that many products will prevent not only crabgrass germination, but also desirable seed germination as well, sometimes lasting on the soil surface for several months. The ideal time to apply a pre- emergent crabgrass control product is between forsythia full bloom and lilac/ flowering dogwood bloom. After that time, crabgrass has probably germinated and it is too late for any pre-emergent herbicide to be effective. See the fact sheet on Crabgrass Control.
Warm spring soils also bring earthworms and grubs to the upper soil levels, and mole activity may be noticed. If mole activity occurs, check the areas of greatest activity and see if grubs may be what is drawing them there. If none are discovered, then earthworms are probably what they are after. This is especially the case along the edges of deciduous woods, where worms abound under the leaf litter. Moles may encroach into the lawn areas as they find worms and tunnel anywhere and everywhere looking for more worms. Spring traps may be used to try and control heavy mole activity. No baits are required, just make sure to set the trap with the support stakes straddling a main tunnel. Hand removal is an option if killing is not. Look for moving ground as the mole tunnels along, and insert a spade or a thickly gloved hand about 12 inches behind where the mole is moving. This will prevent it from doing a U-turn and escaping. Take your other thickly gloved hand and open up the ground where the mole should be. Either fling him out or pick up by the tail- carefully as they will bite. Then do with it as you see fit, being mindful not to toss it into the neighbor’s yard. See the fact sheet Mice, Voles, and Moles.
Grub control in spring can be hard to achieve. The grubs that return to the root zone are different physiologically than they were last fall. They are larger and getting ready to pupate. Most rescue products are not very effective in the spring. The best way to control grubs that are in the same areas of lawn year after year is to either apply a preventative product between June 15- July 15, or use an appropriate biological control product when grubs are known to be present. Make sure to water the product to the root zone of the grass, whatever method of control is used. See the fact sheet Grub Problems in Turf.
It is a good idea to get the lawn mower blades sharpened, if you haven’t done it yet. Sharp blades prevent shredding the leaf tips, which promote disease development in some cases and prevent quick healing to cut leaves. Mowing causes moisture loss to happen until the leaf tips can close, and a clean cut heals the fastest.
Despite good cultural practices, pests and diseases at times may appear. Chemical control should be used only after all other methods have failed.
For pesticide information or other questions please call toll free: 877-486-6271.
All photos ©Pamm Cooper 2016
Revised by the UConn Home and Garden Education Center 2016