Warm-Season Lawns: When It Comes to Spring Green-Up Soil Temperatures Matter!

The primary factor in Bermuda and Zoysia spring green-up is the soil temperature. Bermuda and Zoysia thrive in hot summer temperatures. When soil temperatures at 4” reach 75-80 degrees, it creates optimum root growth. When the soil temperature reaches 80-90 degrees, we have optimum shoot growth.

Why do soil temperatures matter?

While we have experienced some warm days this spring, we have also experienced cool nights. As a result in full sun at a 4” depth, we are seeing soil temperatures on average at 63 degrees, and in shade, we are seeing soil temperatures at 4”  at 58 degrees. In full sun, your Bermuda and Zoysia lawns are starting to show green-up and starting to grow; while in the shade, some Bermuda and Zoysia lawns are thin and have very little spring green-up. We need soil temperatures to consistently average in the 70-degree range in order to achieve full green-up.

Unfortunately, over the next 7 days, our nighttime temperatures range from a low of 38 degrees to a high of 53 degrees which will not help increase current soil temperatures. The good news is the extended forecast does predict an increase in day and nighttime temperatures. Warm-season lawns in full sun will benefit first then as nighttime temperatures increase to 60 degrees, partly shaded lawns will green up.

Good news if you have a Tall Fescue lawn, which is a cool-season grass, it is thriving with these cooler soil temperatures (50 -70 degrees) and will do so until Summer when soil temperatures reach 80 degrees plus.

The Difference in Soil Temperatures

        Bermuda Lawn in Shade – Soil Temp 58°                 Bermuda Lawn in Full Sun – Soil Temp 63°