How to Protect New Grass from Frost (All You Need to Know)

In Gardening, Tips by Jamie

As with any other plant, grass requires the proper conditions to grow. Too hot and dry, and it will get scorched before it even takes root. Too cold, and the roots won’t be able to grow at all. But sometimes, a late spring frost or early fall frost can throw off your plans. So, how do you protect new grass from frost?

There are three main ways to protect new grass from frost. First, you can cover the area, either permanently with peat moss or straw, or temporarily with a tarp. Second, you can wet the ground down to add extra warm water. Third, you can avoid walking on the grass until the frost has melted.

Let’s take a look at how and why these methods work. We’ll also talk about some other questions, such as how to protect seeds from frost, and how to mow when it’s cold out. By the time we’re done, you’ll know everything you need to know about the effect of frost on your grass.

Will Light Frost Kill New Grass?

It depends on how bad the frost is. Juvenile blades of grass are particularly vulnerable to frosts that freeze the surface of the soil. This makes it too hard for their roots to penetrate, so they can’t absorb any new nutrients. As a result, the grass can die off before it even has a chance to take root.

When is New Grass Safe from Frost?

If the frost is only very light, and the top of the soil doesn’t freeze, your new grass will be safe. That said, you don’t want to walk or drive on the grass until the frost is gone. Otherwise, you could still cause damage to the seedlings.

Can I Water New Grass Before a Freeze?

Yes! In fact, it can often be a good idea. If you water the day before a frost, the water from the tap will be far warmer than freezing. And if the soil has a ton of moisture, there will be more mass to freeze. As a result, the odds of the root system freezing will be very low.

That said, this only works when it’s reasonably warm outside when you water. If it’s below 40 degrees, you should forego watering before a frost. You also shouldn’t water if it’s forecasted to drop below 25 degrees for four or more hours.

frost on new grass frozen

How to Protect New Grass from Frost

The first step to protecting your grass from frost is planting at the right time. In the fall, make sure to seed at least six weeks prior to the first forecasted frost. In the spring, wait until at least two weeks after the last frost. This will reduce your odds of having to deal with frost in the first place.

Another way to protect your grass is to insulate it. You can lay down a tarp or a heavy canvas and use it like a blanket. Weigh down the edges with stone or scrap wood, and let it sit overnight. But make sure to remove it in the morning, so your new grass can continue to grow.

Finally, avoid walking on your lawn when it’s frozen. This applies not just to new grass, but to all your grass. When the blades freeze, they become brittle, and you can snap them when you step on them. This causes severe damage, and can even kill your grass.

What About Grass Seeds and Frost?

Will Frost Kill New Grass Seed?

No, frost will not kill new grass seed. Grass seeds go dormant in freezing weather, and will not sprout until it warms up. If you’ve seeded in the spring and got a sudden frost, you should be fine.

How to Protect New Grass Seed from Frost?

Assuming you’ve planted your grass at the appropriate time of year, the ground temperature will be well above freezing. You can use this to advantage, and put a layer of peat moss over your new grass to help trap that warmth. Many people spread ¼-inch of peat moss when first planting their seeds. But it doesn’t hurt to apply a little bit extra if there’s frost in the air. You can achieve the same result with straw, but be very careful that it’s straw, and not hay. Hay has seeds in it, and you can end up with oats or even weeds growing in your new grass.

If you need a quick and dirty fix for a single night, you can even throw down a tarp. Just make sure to take the tarp up in the morning. Otherwise, your fresh grass won’t be getting any sun.

How Cold is too Cold to Plant Grass Seed?

You should only plant grass seed when the average daytime high is above 60 degrees. If it’s cooler than that, there’s a possibility that the soil is cooler than 50 degrees. Once it gets that cold, your seedlings won’t be able to take root. And even if the seeds lie dormant all winter, they might get washed away by spring rains before they have a chance to sprout. This, among many other reasons, is why it’s a terrible idea to plant grass seed in the winter.

Does Straw Protect Grass Seed from Frost?

Yes, provided the frost isn’t too severe. That said, keep in mind our earlier warning about seeds. To make sure you’re not getting any, you need to use actual straw – not hay.

Grass & Frost FAQs

How to Protect Ornamental Grass from Frost?

The best way to protect ornamental grass from frost is with a thick layer of mulch. On sedges and rushes, you can actually mulch all the way over the top of the grass. Be careful about prairie grasses like fescues, though. If you mulch all the way around the crowns, they’re liable to sprout fungus.

Will Frost Damage Fresh Cut Grass?

Yes, frost will damage fresh cut grass. In fact, cutting your grass before a frost can be just as bad for your lawn as cutting immediately after one. To be safe, try to cut at least five to seven days before the first forecasted frost.

Does it Harm the Grass to Rake Away Leaves When There is Frost?

Yes it does. After a hard frost, your grass is easily vulnerable to damage. This is not the time to be dragging a bunch of metal or plastic tines through it. If you want to do a little late cleanup, use a leaf blower instead. It’s gentler on your lawn, and you can leave any aggressive de-thatching for the spring. Just make sure your grass isn’t actually frozen while you’re working, and you’ll be alright.

Is it Bad if My New Grass is Turning Brown After Frost?

It depends. If there was only a light freeze, the grass might just be turning brown as a defensive mechanism. In this case, care for it as normal, and it should come back to life after a couple of days. That said, if the discoloration persists or worsens, there might have been a hard freeze. In that case, you’ll need to reseed in the spring. However, it’s also worth checking for signs of fall brown patch fungus. In this case, you could apply a treatment, and potentially save your grass.

What Temperature Do We Get Frost on Our Lawn?

Your lawn will start to frost as soon as the temperature drops to 32 degrees Fahrenheit. That said, it needs to stay cold for a few hours before the soil actually freezes.