Homesteading, Gardening, and Off-Grid Living

What is the Best Mulch for Tomatoes + How and When to Mulch

By: Zac Friedman


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The best mulch for tomatoes is a loose organic mulch such as straw, hay, grass clippings, pine straw, compost, wood chips, or shredded leaves. Mulching can be really beneficial for your tomato plant. It helps to retain moisture, suppress weeds, regulate soil temperature, and add nutrients to the soil. This can help them grow faster, and stronger. It can also increase yields. This guide outlines some of the best mulches to use for tomatoes and lists some benefits of each. I’ll also explain how to apply mulch to your tomatoes and when to apply it for the best results. 

The Best Mulch for Tomatoes

The 6 Best Mulches for Tomatoes


Straw is one of the best and most popular types of mulch for tomato plants. It’s cheap and it’s available everywhere. All garden centers carry it. It’s also easy to apply by hand. Just grab a bundle and scatter it around the base of your plants 3-4” thick. 

Straw helps to retain moisture in the soil. It also keeps the weeds down by making it harder for them to germinate. Straw also breaks down quickly. When it breaks down, it provides nutrients for your tomatoes and helps improve the soil structure. In addition, straw acts as an insulator and helps keep the soil temperature more consistent. This is particularly important for tomato plants, which like warmer soil.

Both rice straw and wheat straw are good choices. It’s best to avoid hay because it can contain seeds that can sprout and use up nutrients. Straw can also contain weed seeds. To avoid this, it’s best to buy straw that’s made for mulching.

For more in-depth info, check out my guide to using straw for mulch in a vegetable garden.

Tomatoes growing

Shredded Leaves

Shredded leaves also make great mulch for tomato plants. They are easy to apply. They help with moisture retention in the soil. In addition, they help keep the soil temperature more consistent. They also break down and introduce nutrients and organic material into the soil. This is all great for your tomato plants. 

Maybe the best thing about shredded leaves is that they’re free. You can use the leaves that fall from the trees around your home. Just rake them up then shred them and scatter them around the base of your plants.  

It’s important to shred the leaves before applying them. If you don’t, the whole leaves can prevent water and air from reaching the soil. They can also trap too much moisture in the soil and cause root rot. 

Make sure the leaves are crushed or shredded into small pieces to prevent this. You can buy a purpose-made leaf shredder or you can use your lawnmower to shred them up. Some leaf blowers also have a shredding function. 

Grass Clippings

You can also use grass clippings to mulch your tomatoes. Grass clippings are an excellent source of nitrogen. They also help to retain moisture and insulate the soil. The best thing about grass clippings is that they’re free. If you have a lawn, you’ll produce piles of them every week. 

Before applying the grass clippings, be sure to let them dry. If you don’t, they will stick together into a mat. This blocks air and water from reaching the soil. It can lead to mold. 

Make sure your grass clippings don’t contain any chemicals, such as weed killer. This could harm your tomato plants. In addition, you should make sure your grass clippings don’t contain weed seeds, such as dandelions. 

For more in-depth info, check out my guide to using grass clippings as mulch. 


compost bins

Compost is a perfect mulch for tomato plants because it is rich in nutrients. The extra nutrients will help your tomato plants grow stronger and will increase yields. Compost is also a great soil amendment. It will increase the amount of organic material in the soil to improve soil structure. You can add some compost to the soil while you plant and add a layer on top of the soil as mulch. 

You can use store-bought compost or you can make your own from yard waste and kitchen waste. One of the nice things about compost is that it’s free if you make your own from waste and scraps. Compost will break down quickly. You’ll need to add a fresh layer throughout the season.

It’s important to note that most compost is high in nitrogen. Nitrogen will make your tomato plants grow lush and green but they will produce fewer flowers and fruits. To avoid this, try to use a compost that isn’t too high in nitrogen or wait until later in the season after the plants have flowered to apply it. Generally store bought compost is higher in nitrogen because it contains manure. You can make a low-nitrogen compost by adding more ‘browns’ such as dried leaves, straw, sawdust, etc in your compost pile. 

For more info, check out this interesting guide about growing tomatoes with too much nitrogen.

Bark Chips or Wood Chips

Wood mulch

Bark chips and wood chips are popular choices for gardeners who care about aesthetics. These are some of the most attractive mulches. 

There are lots of different options when it comes to bark and wood mulch. Bark comes in a range of different textures from small particles of bark dust to large bark nuggets. Wood mulch can be chipped or shredded into small pieces. A number of different trees are used including pine, cedar, hemlock, oak, and more. These mulches come in different colors from dark brown to red. Pine bark is probably the most popular. 

Bark and wood mulches don’t break down as quickly as other types of mulch. This means they last longer so they don’t have to be replaced as often. The drawback is that they don’t add as many nutrients to the soil as other types of mulch. They are also a bit more expensive. 

Another drawback to consider is that some wood mulches can make your soil more acidic (lower the pH). Tomato plants like soil that is slightly acidic but not too much. If you already have acidic soil, you might want to avoid wood mulch. 

Wood and bark mulches also temporarily deplete nitrogen from the soil. Microbes use the nitrogen in the soil to fuel their activity. This only affects the part of the soil that touches the mulch. After the mulch decomposes, the nitrogen is released back into the soil. Tomatoes need some nitrogen but not too much or the yield will decrease. As long as you don’t mix the wood or bark into the soil, you don’t need to worry about nitrogen depletion.

Cedar mulch can be a good choice for tomatoes because it has some insect-repellant properties. Cedar contains natural oils that some pests don’t like. It also has a beautiful reddish color.

Pine Straw (Pine Needles)

Pine straw is another free type of mulch that you can use for tomatoes. It helps insulate the soil, retain moisture, and suppress weeds. It’s also easy to apply by hand. Another nice thing about pine straw is that it’s free if you have pine trees on your property. 

Before you apply pine straw, you should let it dry out. If you apply it when it’s fresh, it can lower the pH of your soil. Pine straw won’t add many nutrients to your soil but it is still a good soil cover for tomato plants. 

For more info, check out my guide to the pros and cons of pine straw mulch. 

Red or Black Plastic Sheeting

Plastic mulches can be a good option in colder climates. Black plastic mulch absorbs heat from the sun, which helps keep the soil warmer. This helps to prevent the roots from freezing. You can extend your growing season by 2-3 weeks this way. 

Another option is to use red plastic sheeting. This material absorbs heat nearly as well as black sheeting. It also reflects light back onto the plant. This increases photosynthesis. It also has tiny holes that allow water and air to pass through. Red plastic mulch can also help reduce nematode populations. Nematodes are parasites that can eat the roots of your tomatoes and cause damage. 

Plastic sheeting can last many seasons because it is an inorganic type of ground cover. Just make sure you store it properly while it’s not in use so it doesn’t get damaged. 

Other Options

There are plenty of different types of mulch you could use including coffee grounds, cardboard, sawdust, or shredded newspaper. These materials aren’t as good as the above listed options but they can work fine. Peat moss can also be a good choice but it has gotten pretty expensive. It’s also a bit less environmentally friendly because it is being over harvested in some places. You can also use inorganic mulches like rubber chips. These can look nice but they won’t add nutrients to the soil. Natural mulch is always best. 

A tomato plant growing

How to Apply Mulch to Tomato Plants

  1. Select the right type of mulch for your tomatoes- Personally, I think straw is the best type of mulch for tomatoes. If you have another type of mulch on hand already, use it instead. For example, maybe you have a pile of leaves, some grass clippings, or some extra wood chips. It’s best to use an organic mulch that will add nutrients as it degrades. When choosing a mulch, make sure it doesn’t contain any chemical treatments such as herbicides or pesticides. Also, make sure it doesn’t contain any weed seeds. 
  2. Clear the area- Before you apply mulch, remove any weeds around your tomato plants. If there is grass growing around them, remove it. 
  3. Add some compost or manure (optional)-  If you choose, you can add a layer of compost or manure before applying the mulch. This will help add some nutrients to the soil. To grow healthy plants, you need nitrogen, potassium, and phosphorus. 
  4. Spread the mulch around the base of the plant- Apply a thick layer of mulch 2-3 inches deep around the base of your tomato plants. When applying the mulch, don’t let it touch the stem of the tomato plant. Leave a small gap. Also, make sure the mulch isn’t so deep that the leaves of the plant are touching it. If the stem or leaves are touching the mulch, they are more likely to rot. Also, if you apply too much mulch, air and water won’t be able to reach the roots easily. 
  5. Water- After applying mulch, water thoroughly. After watering, stick your finger through the mulch to feel the soil underneath. Make sure it’s wet. If it’s not, your mulch may be blocking the water flow. Remove some. It’s also a good idea to check the moisture level of your soil periodically. Mulch can retain too much moisture and cause root rot. If the soil stays too wet for too long, remove some mulch.
  6. Apply more mulch as necessary- Keep an eye on your plants and periodically add a fresh mulch layer after it decays. Some mulch degrades faster than others. You may need to add some fresh mulch a few times during the growing season. 

When To Apply Mulch to Tomatoes

Late spring is the best time to mulch tomato plants. In some colder climates, you should wait until early summer.

Tomatoes like warm soil but not too hot. Wait for the soil to warm up before applying mulch. If you mulch in the early spring, the mulch can insulate the soil and prevent it from heating up. This can delay harvest. Your tomatoes may not have enough time to fully develop. Particularly if you live in a cold climate.

It’s usually best to wait a few weeks after planting your tomatoes to apply mulch. This gives the soil plenty of time to warm up. You can apply some compost when planting if you choose. 

During the growing season, you can apply more mulch as needed. If the original mulch starts to degrade away and thin out, just add a new layer. 

Tomatoes being planted in a greenhouse in the spring

Benefits of Mulching Tomatoes

  • Mulch retains soil moisture- Mulch helps the soil retain moisture longer by shading the soil from the sun and blocking the wind. This reduces evaporation, which helps the plants stay hydrated. This also helps with water conservation. You won’t have to water as frequently and you’ll save money on your water bill. This is nice if you live in an area with hot and dry summers or if you live in an area that is susceptible to droughts. 
  • Reduces weed growth- Mulch blocks sunlight from the soil so weeds have a harder time germinating. It also helps to block weed seeds that are blown in or dropped by birds from reaching the soil. This is important because weeds take resources away from your tomatoes. They use water and nutrients to grow. Your tomatoes will grow better when they aren’t competing for nutrients with weeds.
  • Mulch regulates soil temperature- Mulch shades the soil to help keep the soil cool during the summer. When it starts getting cooler in the fall, mulch helps insulate the soil to keep it warmer. This can extend your growing season. Mulch also insulates the soil to minimize temperature swings between the day and night. This helps reduce stress on your tomato plant’s roots. This is important if you live in an area with extreme temperatures. 
  • Reduces soil erosion- Mulch blocks the impact of heavy rain. It also absorbs some moisture This prevents soil from getting washed away during heavy rain storms. 
  • Mulch adds nutrients to the soil- As mulch decomposes, it releases nutrients such as nitrogen, potassium, and phosphorus into the soil. These nutrients are necessary for tomatoes to grow. Having plenty of nutrients will increase your tomato yield. You also won’t have to fertilize as often when you use mulch.
  • Improves soil structure- As mulch breaks down, it adds organic matter to your soil. This improves the soil structure. Soil with plenty of organic material holds moisture better. It can also retain nutrients better. It’s more fertile.
  • Prevents soil compaction- The mulch around your tomatoes absorbs some impact from rain and from people walking on the soil. This way, the soil won’t compact too much. The roots can spread more easily when the soil stays loose. 
  • It keeps the tomatoes and leaves away from the soil- The tomatoes and leaves are less likely to rot this way. They are also less likely to be eaten by pests. Make sure the mulch doesn’t touch the stem, leaves, or tomatoes. 

My Experience

I usually use a free type of mulch around my tomato plants. Usually, I use shredded leaves. Sometimes I use grass clippings. I also apply some fresh compost when planting my tomatoes.

In the past, I would buy straw to mulch my tomatoes. These days, I don’t bother because there are so many free mulches available. Why spend money when I don’t have to? 

The best type of mulch for your tomatoes depends on the weather conditions, the soil quality, your budget, and your personal preference. Mulching tomatoes is easy and cheap. Mulching helps prevent weeds from growing, retains moisture, and provides nutrients for your plants. It can help increase yields. It’s well worth your time and effort. There is really no reason not to mulch tomatoes. If you take care of your tomato plants, you’ll end up with a nice harvest at the end of the season.

What type of mulch do you use for your tomatoes? Share your experience in the comments below to help other gardeners!

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The Best Mulch for Tomato Plants
The Best Mulch for Tomato Plants

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