when is it too cold to fertilizer lawn

When is it Too Cold to Fertilize a Lawn?

If you’re going to keep your lawn in tip top condition then you’ll want to make sure that you do the right things at the right time. Fertilizing is very important but you should never do it when the weather is too cold. 

If it is any colder than 60 to 70 degrees fahrenheit, you should NOT fertilize your lawn. During periods below these temperatures, the lawn becomes dormant but the weeds do not. So, the only thing you’ll be feeding are those pesky weeds. 

If you’re wondering when is the best time to fertilize your lawn, this guide has all of the information you need to know. 

When it comes to fertilizing your lawn, you will need to make sure that you do this at the right time of year. Adding fertilizer when it is too cold is a no-no since the lawn will be dormant below certain temperatures.

Once the temperature drops below about 60ºF, fertilizer won’t have an effect on the growth of your lawn because of its dormant state. But it’s also worth remembering that your lawn may also enter dormancy when things turn hot.

red fertilizer spreader

Frost happens when moisture builds up on the lawn in cold temperatures. This creates a frozen layer over the lawn. When this happens, the growth rate of the lawn will slow down dramatically. That said, this doesn’t mean that the lawn has died and it does still need all of those important nutrients to help it thrive.

For this reason, it’s always a good idea to try to have one final application of fertilizer during the late fall before the first frost sets in. This will allow the lawn to build up nutrients before it freezes over.

Is Frost Bad For Fertilizer?

Lawns need a nitrogen rich fertilizer but the problem is that, during colder temperatures, applying this can result in softer growth which is more susceptible to frost damage.

What’s more, the fertilizer won’t have an effect on the already dormant lawn so you won’t be providing any benefits to its growth. As we have mentioned, the only real benefit will be to the weeds which will quickly take over.

Check The Soil With A Thermometer

It can be difficult to judge the temperature of the soil even if you’re confident about the air temperature. If you want to avoid fertilizing at the wrong time then it’s best to check the soil using a thermometer.

You can buy soil thermometers online and the great thing about them is that they’re incredibly easy to use. You simply take the probe and insert it into the ground by about three inches. You can check the temperature every day over a period of time to get the most accurate result.

If you don’t want to use a thermometer or you would like to back up your findings, you can also use a soil temperature map. This can be accessed online and all you need to do is pop in your location and it’ll tell you the current temperature.

Using one of these maps along with a thermometer will give you the most accurate information. Also keep in mind that the soil temperature will vary across the course of the day and will be drastically cooler in the evening.

Different Types Of Grass

Thinking about the best time to fertilize doesn’t only mean considering the temperature but also the type of grass you have in your yard.

There are two main types of grasses; warm season grasses and cool season grasses. For most people with warm season grass, there won’t be an issue with when it’s too cold to fertilize as the temperature probably won’t drop low enough for there to even be any frost.

Warm Season Grass

Warm season grasses like centipede, zoysia and Bermuda usually thrive in zones 7 to 10 as they need hot weather. But with that in mind, there are some areas within these zones, where the weather doesn’t remain hot all year round and there may be a frost.

For this reason, it’s impossible to say with certainty the best day to fertilize your grass each year. It very much depends on the local climate.

For warm season grasses, you will need to wait until the temperature of the soil goes above 70ºF. Generally speaking, you’ll want to fertilize the lawn between every four and eight weeks to keep it at its healthiest. However, if you can’t commit to this, you’ll want to at least commit to fertilizing once in the late spring.

frosty grass

Cool Season Grass

For those that live in zones 1 to 6, it’s likely that you have a cool season grass. This includes things like tall fescue and Kentucky bluegrass. These grasses thrive in cooler climates so it’s best to fertilize them outside of hot weather, avoiding summer and opting to fertilize in the spring. Of course, you will need to wait until the frost has passed.

What Time Of Year Is Best For Fertilizing A Lawn?

The best time of year to fertilize a lawn really depends on where you are. Zones 7 to 10 have vastly different temperatures to places like zones 1 to 6. Moreover, there are some zones that won’t experience frost and frost is one of the main issues when it comes to fertilizing a lawn effectively.

Since the lawn goes into a dormant state when it is frozen, any fertilizer you add will only serve as a food for the weeds which remain hardy all year around. Even when spring rolls around, your lawn might look as though it’s thriving but it won’t take long before the weeds take over.

The best time to fertilize your lawn is during the spring. However, you need to make sure that the temperature during the day is above 60ºF, preferably closer to 70ºF. This means that, in some places, early spring may still be too cold so it’s important to pay attention to the weather and plan your law fertilization around this.

drop spreader

But it isn’t only the weather, you’ll also need to make sure that the soil temperature is correct. While the air temperature may be 60 or more, the soil is likely a little cooler. That’s why it’s important to use a thermometer to check this before you apply anything.

Also keep in mind that one of the main reasons you are using fertilizer is to strengthen the roots and keep them healthy. While adding fertilizer in cold temperatures might promote shoot growth, this won’t be of any benefit to the roots.

In a lot of places, the weather in early spring is not all that dissimilar to what you’ll have seen over winter. So, it’ll still be too cold. That said, it is possible to go in the other direction and apply fertilizer when it’s too hot in the height of summer.

Final Thoughts

Fertilizing your grass is essential for healthy growth and a lush green lawn that you can be proud of. However, there may be certain times of the year that applying fertilizer is nothing but a waste of time. You see, when you apply fertilizer to frozen grass, this will do nothing to benefit it.

In fact, while the lawn may be dormant and won’t take the nutrients it needs from the fertilizer, any weeds within the lawn will thrive on this nutrient boost. Come spring, the lawn won’t be healthy but those weeds will have been given a head start.

To be sure that you’re giving your lawn the best chance, only apply fertilizer once the temperature is between 60 and 70 degrees fahrenheit. Be mindful that it’s also possible to apply fertilizer when it’s too hot so sticking to spring application is the best idea.

Further Reading

Andrew Fisher

Andrew Fisher

Andrew is a dedicated father of three who really takes pride in his lawn and garden. You'll find Andrew behind the scenes of almost everything Edge Your Lawn produces. When he's not helping readers find all the information they need, he's in his backyard working on his lawn and garden landscaping. This year he hopes to build an outdoor deck and sort out his veg patches.

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