Let it warm up before you fertilize your lawn

By Larry Williams, UF/IFAS Extension Agent, Okaloosa County

It’s too early to fertilize our warm-season lawngrasses in February. This includes the use of fertilizers contained in weed-and-feed products. Fertilizing too soon can cause more problems than it solves.

There are a number of reasons why it’s best to wait to fertilize your lawn.

First, the soil temperature is too cool for grass roots to have access to some of the fertilizer elements. Certain elements such as iron and potassium are poorly available to the roots until the soil warms up in spring. Some nutrients will leach below the grass roots because the grass can't use them yet. This results in a waste of fertilizer, time and money.

Secondly, fertilizing too soon can induce nutrient deficiencies and off color areas in your lawn. This is why many lawns have bright yellow areas in early spring. Nitrogen is readily taken in even under cool soil conditions. The nitrogen then stimulates new green leaves. The new green leaves that are forced by the early application of nitrogen then become dependent on iron being readily available. But it’s not under the cool soil conditions. So ultimately, you cause a nutrient deficiency by fertilizing too early. Many times, as the soil temperature warms, iron becomes available and the lawn turns green. But why cause this scenario in the first place by fertilizing too early?

It takes consistently warm night temperatures to allow the root area to become warm enough for best root growth and subsequently optimal uptake of the fertilizer.

Thirdly, the young, tender grass roots that are beginning to grow in early spring are easily burned by the fertilizer.

Fourthly, fertilizing too soon can result in tender top growth which is easily injured by a late frost. The average date for our last killing frost is mid March.

Also, be very cautious about using weed-and-feed lawn products that recommend a late winter application. These products are usually very high in nitrogen, which will cause your lawn to begin growing too early. Our southern lawns do not need fertilize during the winter because they aren’t growing. If you’re trying to control weeds, it’s best to apply your herbicides separately from fertilizer, anyway.

In North Florida, it’s best to wait until your lawn has completely greened up in spring before applying any fertilizer.

Some people want to “jump start” their lawns before our weather will allow our grasses to grow. Waiting allows for more efficient use of the fertilizer. You will not injury you lawn by waiting to fertilize but you can certainly injure your lawn by fertilizing too early.

So, have patience, allow your lawn to green up on its own and then fertilize, even if it’s not until April or May.

Originally published Feb., 2006