Soil Temperature and Your Grass
As we’ve seen this spring, air temperature can be very volatile. One day it can be 70 degrees, and the next, 40! March and April in Iowa can be a trial for your lawn and garden. This can be very confusing when it comes to deciding how to care for your lawn. Lawn care is highly weather-dependent, after all.
It was below freezing last night! What should I look out for?
Even as soil temperatures slowly rise, the air temperature rises and dips, which is hard on newly-budding plants and the crowns of your grass. Was it close to or below freezing last night? Take care to wait until the sun has been on your lawn for a few hours before going out on your lawn. The top part, or crown, of grass blades are vulnerable to breakage, which stunts or even halts their growth.
Should I seed in spring?
Grass, like all plants, need water, light and warmth to survive. If you have a lawn shaded by trees, spring is an excellent time to seed with shade-tolerant grasses, as the trees haven’t yet leafed out, allowing for maximum sun exposure. You can also seed in spring if you have not put down crabgrass pre-emergent, like what is present in our Early Spring and Spring Lawn Health Care applications. Have a Spring application upcoming and you’re planning to seed? Let us know and we can change your application to fertilizer-only. Though a weed, crabgrass is an annual grass that grows from seed, just like the seed you want to put down – pre-emergent unfortunately doesn’t know the difference between the two! If you’ve already put down pre-emergent, either you can seed in the fall, or break the pre-emergent barrier by breaking up the soil with an aeration, seeding machine or hard rake and seed where the barrier is broken.
But is it too cold to seed?
Not at all! As the world emerges from winter, there is a much more dependable indicator of when to seed, and that is soil temperature. The temperature of the air can rise and fall quickly, but soil and ground water retain and lose heat much more slowly than the air, and soil temperature is a major factor in cuing your grass seed to germinate, or sprout, along with moisture and sunlight.
The most common turfgrass species in this area are Kentucky bluegrass and perennial rye, both cooler-climate grasses, often mixed in your lawn and mostly indistinguishable from each other. Kentucky bluegrass germinates between the soil temperatures of 59-86 degrees and takes 20-30 days to germinate, while perennial rye needs a range of 68-86 degrees and 5-10 days to sprout. This means that in spring your lawn is already beginning to green up as soon as the soil warms to spring temperatures, even if the air is still cold.
How can Quality Care help me?
We’re your neighborhood experts and we’re here to help! We offer overseeding with aeration in the spring and fall depending on your lawn’s needs, which is great for filling in thin spots or making your healthy lawn thicker. We have seeding machines for bare spots, or if you’ve already put down pre-emergent for crabgrass. Not sure what your lawn needs are? Drop us a line!