What’s the Best Temperature to Start Working on My Lawn?

Like other lawn care tasks, patience is a virtue when planting grass seed. Reseeding your lawn too early will not get you faster results.

Depending on where you live, spring may be in full swing right now. Our friends in Kansas City and Louisville, for example, are watching tulips pop and grass seedlings sprout. In some parts of the country, like Florida and California, spring work takes on an entirely different feel. The distinctive seasonal changes don’t exist. They’re more subtle.

Here we’ll focus on that magical time when cold winter weather loosens its grip and brownish grass begins to green up and grow.

What Is the Best Temperature to Begin Working on My Lawn?

The best thing to do as March fades and gives way to April is … nothing. Until the snow is gone, the ground firms up and soil temperatures warm, nothing is going to happen with your lawn.

It can be painful to remain idle when you envision all the things you want to do. Don’t try to force it. Leave the rakes, spreaders and mowers in the garage for now. Spend your time planning, purchasing supplies and witnessing Mother Nature’s beautiful work unfolding before your eyes. Let your lawn wake up on its own. You have the entire summer to work on it.

When Does Grass Begin Growing?

As simple as it may sound, the first indicator your grass has awakened is when it starts to green up again. Some grasses are slower to green than others, so be patient. Most lawn work shouldn’t be done until you mow the first time. That’s your signal that it’s okay to start fertilizing, applying weed killers and possibly sowing some grass seed.

Your lawn wakes up once soil temperatures reach about 55 degrees F. How quickly this happens depends on ambient temperatures, soil moisture content, your lawn’s proximity to direct sunlight and soil type. Sandy, lighter soils will warm up quicker than heavy, clay soils.

Get yourself a soil thermometer. They’re available online or at many garden centers. One like the Vee Gee Scientific Soil Thermometer is inexpensive and easy to use. Sticking it four inches into the ground for about 15 minutes will give you an accurate reading.

Once soil temperatures remain in the upper 50s, it’s time to apply pre-emergent herbicides. Reliable meteorological indicators will help you time these crabgrass control applications. Watch for lilacs or forsythias beginning to bloom, or three consecutive days with highs reaching 70 F. Then it’s game on!

What Is the Best Time to Start Planting Grass Seed?

Like other lawn care tasks, patience is a virtue when planting grass seed. Reseeding your lawn too early will not get you faster results.

Soil temperatures need to be warm enough to trigger seed germination. That can vary depending on the grass species. Perennial ryegrass will germinate when soil temperatures are still in the upper 40s; they’ll be the first seedlings you see. Kentucky bluegrass and tall fescue like warmer soils, so seeding these too early can yield disappointing results.

While you can grow grass in the spring, soil temperatures are most conducive to seedling emergence in late summer or early fall. That’s the best time by far to focus on thickening up your lawn. As much as you want to focus on lawn care in the spring, some things are best left for fall. Seeding is one of them.

How Does Cold Affect the Lawn?

All things green and growing need warmer springtime weather to promote growth and plant health. Plant growth slows down in cooler weather. That’s a good thing, especially during the dog days of summer when many plants, including lawn grasses, are simply trying to survive the heat. But in the spring, it can be frustrating when you’re anxious to get going on your yard work and everything is sluggish to grow.

Cold weather will delay weed growth in your lawn, too. It’s difficult to predict crabgrass germination with calendar dates, since spring’s arrival varies from year-to-year and location-to-location. Green Industry researchers have found daytime temperatures offer a more precise way to predict weed seed germination. The accumulation of Growing Degree Day (GDD) units can predict the likelihood of weed germination and even some insect development.

Tracking growing degree days with the GDDTracker Tool can take the guesswork out of planning pre-emergent applications. It’s a handy tool that uses your zip code to match weather history data to current growing conditions, telling you exactly when to apply your crabgrass control.

Joe Churchill
Joe Churchill is a Senior Turf Specialist for Reinders, Inc. in Plymouth, MN with a passion to promote realistic and environmentally-sound turfgrass maintenance practices through responsible use of water, fertilizers, pesticides and other inputs. Joe's client base includes professional turf managers serving the lawn care, sports turf and golf course industries. His lawn is the envy of the neighborhood and, in his free time, he enjoys kicking back on the Northshore of Lake Superior.