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When To Fertilize Cool Season Grasses

To achieve optimum turf health, it's important to apply fertilizer at the proper times.

In this FAQ, Christina Burton, Maintenance Channel Manager for Horizon, describes when to fertilize cool season grasses like Kentucky Bluegrass, Perennial Ryegrass, Tall Fescue and Bent Grass.

Cool Season Grasses And Fertilization - Video Transcript

So as we talked about, cool season grasses include those such as Kentucky Bluegrass, Perennial Ryegrass, Bent Grass, Tall Fescue. They are the grasses that, generally speaking, are most actively growing in the spring and in the fall.

In true seasonal climates, particularly those that receive snow (The Midwest, the mountains). Those grasses are actually going to go dormant during the winter. In a lot of coastal, more temperate regions, where these grasses might grow. They still are growing although typically a lot slower in the winter than in the spring and in the fall.

You might ask why it’s a bad idea to fertilize in the summer versus keeping it more concentrated more towards these spring and fall windows. And the reason is in the summer, particularly when you’re going through a hot spell, those grasses are really kinda stressed out. They’re trying to slow down. They’re trying to conserve energy and they do this through their root system.

So when you fertilize, particular heavy or with a quick release, you’re having that plant expend a lot of energy creating top growth and they can only do that at the expense of the root system. So you end up with a weakened stand. So that’s why you avoid summer.

And same for winter. In those areas where it’s growing, although not that actively. It’s fine to fertilize then. It’s not really that important to overall turf health. It’s more about esthetics. And often times contractors are sort of forced to fertilize more in winter because the consumer wants to see green turf.