Homesteading, Gardening, and Off-Grid Living

Using Hay as Mulch for Your Garden: Pros and Cons

By: Zac Friedman

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Hay can make a great mulch for your garden. It’s affordable and easy to spread. Hay also helps to retain moisture, suppress weed growth, and insulate your soil. It adds nutrients and organic materials to your soil as it decomposes. Of course, there are some drawbacks to consider. Hay doesn’t last as long as other types of organic mulch. It can also contain weed seeds. This guide outlines the pros and cons of using hay as mulch in your vegetable garden. I’ll also explain how to apply hay properly and when to mulch for best results.

Should You Use Hay for Mulch in Your Garden?

What is Hay?

Hay is a plant that has been cut and dried. It is usually made from a type of grass or legume. It is cut while it is still green, before it has gone to seed. After it is cut, it is dried and baled. Hay is usually used as livestock feed but can also make a great mulch. It also works well on garden paths.

Hay is different from straw. Many people confuse these two. Straw is made from plant stems from grain crops such as wheat, oats, barley, rice, etc. It is the dry stock that is left over after the grain has been harvested. Straw is basically a byproduct of agriculture. It has very little nutrients left in it. Straw is used as animal bedding because it insulates well. It can also make a good mulch. For more info, check out my guide to straw mulch here. Straw is actually a more common mulch than hay. 

Benefits of Hay Mulch

It’s Affordable

As far as mulches go, hay is one of the cheaper options. On average, a small bale of hay costs $3-$10, depending on where you live and the quality. Summer hay is cheaper than winter hay and non feed quality hay is cheaper than feed quality. 

One bale of hay will cover around 70-80 square feet at a depth of 3”. You may need to re-apply once or twice per season as the hay decomposes. For an 80 square foot garden, you might need around 3-4 bales. This would cost you around $12-$40 per year. 

To compare, 1 yard of wood mulch, bark mulch, or compost will cover around 80 square feet of space at a depth of 4 inches. 1 yard of mulch costs around $30-$40. You usually only need to apply once per year. 

On average, you might save $10-$20 per 80 square feet of garden space. If you have a lot of garden space, the savings can really add up. If you only have a small backyard garden, the cost difference is minimal. 

Hay Mulch is Easy to Apply

It’s easy to spread hay by hand. Just loosen the bale up and grab a bunch with your hands and spread it to the appropriate depth around your garden. You can use a rake to help spread it. You don’t need a shovel or wheelbarrow or any type of tool to spread hay 

Planting with hay mulch can be a bit more of a challenge. You have to move the mulch out of the way so you can reach the soil. You can’t plant directly in hay mulch. Weeding can also be a hassle. You have to move the mulch out of the way so you can get to the weeds. 

A farmer pulling a wheelbarrow of hay

Hay Provides Nutrients for Your Plants

Hay is cut while it’s still green and high in nutrients. It needs to be nutrient rich because it is used to feed animals. Animals need lots of protein to grow. 

When you use hay as mulch, it releases nutrients into the soil as it breaks down. Hay contains phosphorus, potassium, nitrogen, and magnesium. These nutrients improve the fertility of your soil. These are all important nutrients for plant growth. 

The hay also adds organic material to the soil as it decomposes. This improves the soil structure. Soil with lots of organic matter retains water better and allows for better water infiltration. The hay also helps build soil mass. When hay starts to break down, you can till it into the soil and add a fresh layer or just add more. 

Hay Helps Retain Moisture

The hay slows the evaporation of water from the soil by shading the soil from the hot sun and blockchain the wind. This moisture retention property is helpful in hot, dry, and windy climates as well as areas that are susceptible to drought. 

Moisture retention benefits your garden in a few ways. You don’t have to water as frequently. You won’t spend as much time watering and your water bill will be lower. Water conservation is also good for the environment. A consistent soil moisture level is also good for your plants. 

A bale of hay

Hay Insulates the Soil

Hay acts as a natural insulator. It keeps the soil cooler in the summer and warmer in the winter. This helps protect your plant’s roots from extreme heat or cold.  

During the summer, the hay shades the soil from the sun. This prevents the soil from overheating, which reduces stress on your plant’s roots. This is important if you live in an extremely hot environment. 

During the winter, the hay creates a barrier between the soil and the ice and snow. The hay also helps trap the remaining heat in the soil. This keeps the soil warmer. Hay mulch can actually extend the growing season slightly. Your plants will continue growing later into the season because the soil will stay warmer. It won’t freeze as early. This can improve yields.

Hay also helps to reduce soil temperature swings between the day and the night. It keeps the soil cool during the day and warmer at night. This can reduce stress on your plants. This is important in regions that experience extreme temperature swings.

It Prevents Soil Compaction

Hay is a loose mulch. It doesn’t easily compact. It allows air and water to easily pass through. Hay also absorbs the impact from rain and foot traffic to prevent the soil underneath from becoming compacted.

When the soil stays loose, your plant’s roots can easily spread and grow. Loose soil also allows water, oxygen, and nutrients to pass through the soil. This resistance to compaction helps maintain soil health.

Bales of Hay are Easy to Transport

Hay comes packed in bales. There are small square bales and large round bales. The hay bales are tied together with baling wire or twine. It’s not loose like other mulches. This makes it really easy to transport. You can carry a small bale in the trunk of a car. It’s also easy to transport the bales around your yard with a wheelbarrow. 

It Reduces Erosion

Hay absorbs some water and slows runoff. This helps keep the soil in place during heavy rain. It also reduces nutrient leaching. Hay mulch can be helpful in areas that experience erosion. It’s best not to leave the soil surface bare.

Hay is Environmentally Friendly

Hay is a natural material. It is just made from plants. Over time, it breaks down completely and turns into soil. Hay is also a renewable material. It grows quickly, unlike trees that are commonly used for mulch. You also don’t need to use fresh hay. Spoiled hay makes great mulch. It doesn’t have to go to waste if it goes bad and starts to compost.

Of course, not all hay is environmentally friendly. Hay that has been treated with chemical herbicides or fertilizers could introduce some chemicals into your soil. When choosing hay, look for an untreated, organic variety. 

Drawbacks of Hay Mulch

A flower growing in hay mulch

Hay Can Contain Chemical Residue

Hay can contain residue from chemical herbicides or chemical fertilizers. Farmers use herbicides for killing off weeds and they use fertilizers to replenish nutrients in the soil. If you’re trying to keep your garden organic, this can be an issue. You won’t want these chemicals in your soil and around your plants. 

Even if you don’t care if your garden is organic, herbicide residue can still be an issue. The reason is that the type of herbicide used is designed to kill broadleaf plants. This can be an issue if you’re trying to grow broadleaf plants, like tomatoes, cabbage, turnips, etc. The herbicide residue could stunt or kill your plants. 

When shopping for hay for mulch, it’s important to know the source. Look for an organic variety that hasn’t been treated with herbicides or fertilizer. It won’t have any harmful residue on it. If you can, buy your hay from your local farmer. That way, you know where it comes from.

Hay Can Contain Weed Seeds

This is probably the biggest drawback of using hay as mulch. It can contain lots of weed seeds. Pretty much all hay you buy will contain at least some seeds. Usually, there are some grass seeds in it. You may spot some seed heads. It’s unavoidable.  

Hay can contain a variety of nasty weeds including Johnsongrass, Bermuda, or even bindweed. Once you introduce these weeds into your garden, they can be incredibly difficult to get rid of. They can quickly spread. 

There are a few ways you can reduce the number of seeds in your hay. You can leave the hay out for about a year until it partially decomposes. By this time, most of the weed seeds will have germinated and started to decompose as well. The problem is that this makes the hay much harder to spread. You also have to wait to use your mulch.

You can also tarp your hay. Spread it out, saturate it with water, then cover it with a tarp and leave it for a month. Preferably in hot weather. This will trap heat and moisture, causing the weed seeds to germinate. The heat will then kill off the weeds. 

It may also be possible to solarize the bales by wrapping them in plastic and setting them out in the hot sun. The sunlight may heat the bales enough to kill off the weed seeds. They would need to get up to around 130 degrees to kill most of the weeds off. If you live in a hot climate, this will work.

It is also possible to shake some of the weed seeds out. This may work if you’re only mulching a small area. You will still need to do some weeding. 

If some weeds start sprouting, you can simply apply another layer of mulch to help smother them. This is also a good option. You could start with 4” of hay. If weeds sprout, add a couple of inches to smother them.

It Can Attract Pests

Hay can attract rodents. They enjoy burrowing into the warm and soft hay. Snakes can also burrow in hay to hunt for rodents. Some insects are also attracted to hay.

One way to keep rodents away is to regularly water. They won’t live in the wet material. If you have a serious rodent problem already, it’s best to avoid hay.

It Doesn’t Last Long

Hay decomposes much faster than other types of mulch such as wood chips or bark. It doesn’t last as long and it needs to be replaced more frequently.

You’ll have to apply a fresh layer of hay at least twice per year. On average, gardeners add a layer of hay once per season. Once in the spring, once in the summer, once in the winter, and once in the fall. If you want to keep the hay looking fresh, you’ll may have to add a bit every month or so. This adds a lot of work. You can simply apply a new layer over the old. You don’t have to remove the old hay. 

Other types of mulch can last much longer. Most gardeners apply a fresh layer of wood chip mulch or bark mulch once every other year. Some types of mulch, such as cedar chips, can last 3-4 years. Inorganic mulches, like lava rocks last far longer.

It Can Blow Around in the Wind

Hay is a lightweight material. A strong wind can blow it around. Some of the hay might end up on your lawn. In this case, you’ll have to rake it back into your garden beds. 

The wind can also make the distribution of the mulch uneven. There may be bare spots after a storm. You might have to use a rake to re-spread parts of it after the wind blows it around. 

Usually, this is only an issue when the hay is fresh. After it gets wet and begins breaking down, it stays in place better.

Hay Can Get Moldy

Hay soaks up lots of water and stays wet for a long time. If you live in a wet climate, the hay may not have time to dry out. In this case, it can get moldy. Mold can harm your plants if it spreads. For this reason, hay isn’t the best choice for wet or humid environments. 

Looks

Looks are subjective but I don’t think hay is the most attractive mulch. For this reason, I wouldn’t use it in my front yard. I only use it in my vegetable garden in my backyard.

If you live in the city, hay mulch might not blend in. It makes your property look like a farm. For aesthetics, I prefer cedar mulch and pine bark.

Bales of hay

How to Mulch With Hay

  1. Prepare your garden- Start by removing any weeds. If your garden soil is of poor quality, consider adding a layer of compost or manure on top. You don’t need to till. 
  2. Loosen the hay- Hay comes in compacted bales. Cut the bale open and loosen the hay so it’s not compacted. You can simply use your hands to pull it apart and loosen it.
  3. Remove or kill weed seeds- You can try to shake the seeds out, leave the hay out to compost, or tarp the hay to kill off the weed seeds. If you start with a high-quality seed-free hay, you can skip this step. Good hay will contain very few seeds. 
  4. Spread the hay- Use your hands to evenly spread a thick layer of hay over your garden. The layer of hay should be around 4-8” deep. It will settle a bit over time. Be careful not to cover up seedlings or plants so you don’t smother them. When your plants are seedlings, only apply a thin layer of hay. Add more when they’re larger. If you’re spreading hay over old mulch or another type of mulch, the total depth of mulch should not exceed 4”. Don’t apply too much straw or you can limit airflow and moisture. If you’re spreading only hay you can pile it thicker if you choose. You can layer hay up to 8”. Try not to apply too much mulch or it can smother your plants.

When to Apply Hay Mulch

You can apply hay mulch in any season. Most gardeners apply it in the early spring. This is the best time to mulch if you live in a dry area. The mulch will trap moisture and help keep the weeds down. You may need to apply another layer in the late summer because hay breaks down quickly. 

Hay also makes excellent winter mulch. Apply it before the first frost to help insulate your plants during the frigid winter months. 

If you have some hay left over at the end of the season, you can put it in your compost pile. Making compost is a great way to use up hay. You could also save it and use it next year.

My Experience

I like to use hay on my vegetable garden. It’s a great mulch for tomatoes, zucchini, peas, potatoes, cucumber, strawberries, and pretty much any other crop I grow. Sometimes I use straw if straw bales are cheaper. Sometimes, I use a free mulch like pine straw (pine needles), shredded leaves, or grass clippings. Last year, I used hay all season and it worked out really well. I don’t use hay in my front yard because it’s not the most attractive mulch, in my opinion. Instead, I use a wood mulch or bark mulch, like cedar. 

Hay can make a great mulch. It’s affordable and easy to work with. It also helps retain moisture, insulate your plant’s roots, and provide nutrients for your plants. The biggest drawback is that hay can contain weed seeds. Some residue of herbicides and fertilizer. You can mostly avoid this by choosing a high quality organic hay. Another consideration is that hay doesn’t last very long. You will have to reapply it periodically. 

Do you use hay mulch in your garden? Share your experience in the comments below!

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Should You Use Hay for Mulch in Your Garden?

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