Too Early To Fertilize Lawns

Passions run deep where lawn care is concerned. Most of us know someone who obsesses over their lawn, mowing at neat alternating diagonals, and avoiding footprints and out-of-place wheel tracks which would mar the picture-perfect ambience. The rest of us just want the grass green.

Fertilizing is a big part of the lawn care ritual. National fertilizer manufacturers promote their product with a frenzy, as though your lawn will die a quick and painful death if you don’t hurry. Should we rush to fertilize our lawns in early April so they’ll “green up” more quickly?

No, according to recent research reports from North Dakota State University, South Dakota State University, University of Minnesota, Iowa State University, Purdue and Cornell. All agree that lawns Should not be fertilized in April. In fact, all recommend waiting until the grass is green and growing in mid-May or towards Memorial Day before applying fertilizer.

Fertilizing early in the season, like April or early May, causes a rapid flush of lush green grass growth at the expense of the root system. The over-production of grass blades stresses the grass plant, leaving the roots in a weakened state. Waiting until Memorial Day allows the grass plant to grow naturally, begin normal growth, and better utilize the fertilizer once it’s applied.

This is contrary to the hurry-up-and-fertilize philosophy that is very prevalent. Lawns are being fertilized while they are still brown with just a few green shoots starting. And that’s not good.

Oh, the grass will green up and look nice when fertilized early, but over time the stressed-out grass plants cause the lawn to be more susceptible to weeds and disease. Over-fertilized lawns become weaker in the long run. More weed killer and other chemicals are needed. Then more fertilizer is applied to coax the grass to fill in areas left bare from weeds and disease. The vicious cycle revolves.

Here’s the preferred fertilizer recommendation: The best time to fertilize is in fall, around Labor Day. That’s when fertilizer has the most benefit for a healthy grass plant with healthy roots. If you’re going to fertilize once a year, do it around Labor Day. The secondary fertilizer application can be made in spring around Memorial Day.

By the way, if you don’t bag your grass clippings, but instead allow them to filter back into the lawn, the clippings release nutrients into the soil, giving the equivalent of almost one fertilizer application per year.

Happy Gardening!

2 Responses

  1. I never know when it is right to put fertilizer on my lawn, so sometimes I don’t do it. So May is the earliest that someone should put it on their lawn. I will have to do that, so my lawn can look the best it can.

    1. Don Kinzler

      Even if you don’t add other fertilizer, allowing the clippings to return to the lawn while mowing, rather than removing them equals about one fertilizing per year, so that helps also. Good luck with the lawn

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