Best Mulch For Tomato Plants (and Its Surprising Benefits)

Last Updated: April 7, 2023

One of the best tricks for a healthier garden is to use mulch. Homeowners will be familiar with wood chips or bark mulch around their landscaping, but it can provide huge benefits for tomatoes in the veggie garden, too.

In this article, I’ll share all the benefits of mulching tomatoes, and why you should start using it today. I’ll also tell you my favorite types of mulch to use, because the options are plentiful.

Best Types Of Mulch for Tomato Plants

There are two important factors to consider when choosing an ideal mulch for tomatoes:

1. Releases nutrients. The best mulches are made up of organic materials. Think of a big forest where the ground is covered in fallen leaves. Those leaves are slowly breaking down, releasing nutrients and keeping the soil ecosystem healthy.
2. Allows water to pass through. If mulch blocks water from reaching the tomato plant’s roots, then it is a bad choice. Your plant’s roots need water, and some materials may become hydrophobic if allowed to dry too frequently.

With these traits in mind, let’s go through some of the best mulches for tomatoes (and many other garden vegetables).

Leaf Mulch

Leaf mulch is arguably the best mulch for tomatoes, period. The benefits are numerous, and it is usually available for free.

Again, think about forests full of trees, dropping their leaves each fall. Those leaves revitalize the soil, adding nutrients back to where they are needed, and provide food for beneficial animals and bacteria.

To use leaves as a mulch:

• Gather the leaves in fall
• Chop the leaves finely using a lawn mower or a weed whacker
• Allow the leaves to sit in a pile over the winter months (at least 3-4 months)
• Use the leaves in the spring as a mulch

If you don’t have many leaves on or near your property, ask neighbors if you can take some off their hands. Most people simply want to get rid of the leaves that fall on their lawn, but you can put them to good use!

Straw

I have used straw as my primary garden mulch for several years, simply because I didn’t have easy access to free leaves. Straw consists of the dried stalks of cereal plants.

Caution: Straw can sometimes contain herbicides used on the original cereal crop fields. These can be persistent, meaning they will not break down, and can impact your garden. Always test your straw in a controlled fashion before using it as mulch.

If you have a reliable source for straw, then it makes a great, long-lasting mulch. I use the same straw for multiple years, pulling it back in spring the transplant out tomatoes, peppers, and many other seedlings.

Wood Chips

Commonly used in landscaping or shade gardens, wood chips make an excellent garden mulch. There are many myths surrounding wood chips and their affect on the soil, but most of them are not true.

Some examples are that wood chip mulch makes the soil acidic, or that wood chips can steal nutrients from the soil. Neither of these are true when the chips are used only on the surface of the soil (you shouldn’t be working any mulch into your soil).

The bottom line is that wood chips are organic, and will break down slowly, releasing nutrients back into the soil in the process. If you have easy or free access to wood chips, they may be the perfect mulch for your tomatoes.

Living Mulch

Thus far, we’ve only discussed the use of dead plant material as mulch. Another option is to plant low-growing plants around the base of your tomatoes to act as mulch.

One great example is to use alyssum as a living mulch. The alyssum grows to 4-6″ tall under the tomato vines, protecting the soil, attracting beneficial insects, and suppressing weeds. Get alyssum seeds here.

While this type of mulching is more labor intensive, it can lead to some truly beautfiul gardens! I highly recommend trying this if you are growing tomatoes in pots by simply sprinkling some seeds around the perimeter in early spring.

Lawn Clippings & Pine Needles

Another free resource that can be used as mulch are lawn clippings. The grass quickly dries out and becomes a simple, nutrient-releasing mulch.

However, be careful not to use your grass clippings if you treat your lawn with pesticides or herbicides. These can leech into the soil, affecting the growth and potentially the safety of your veggies.

Another similar resource that can be used as a mulch are pine needles. I have used pine needles as mulch around garlic, and they work well, allowing water to easily pass through. Despite what you may have heard, they do not make the soil acidic.

Plastic Mulch

While I am not a huge fan of using plastic in the garden, it is undeniably an easy and effective mulch. It is easy to set up and not messy to clean up after the season ends.

You can also choose the color of the plastic mulch to have different effects. Black plastic mulch warms the soil for heat-loving veggies. White plastic can deter some insects.

The basic technique is to lay out plastic mulch and cut holes in order to plant your seedlings. The holes should be large enough to allow water to reach the soil and root systems.

Benefits Of Mulching Tomatoes

With the best types of mulch for tomatoes covered, let’s take a deeper look at the many benefits of using mulch in the garden.

• Retains moisture. One of the best ways to avoid cracking tomatoes is to water evenly. Mulch helps retain moisture and prevents water from evaporating quickly, leading to healthier plants.
• Suppresses weeds. Weeding can be a huge waste of time. Mulch prevents weed seeds from germinating, so you can spend your time tending to your tomatoes instead of pulling weeds all day.
• Adds nutrients. As I’ve mentioned, most of the best mulches slowly add nutrients back into the soil. As leaves, straw, wood chips, or grass clippings sit, they are slowly broken down by bacteria and animals, leeching out simple nutrients back into the soil. Tomatoes love nutrients, so this effect is a big plus. It is not, however, a complete replacement for organic fertilizer.
• Decreases disease in tomatoes. In addition to bottom pruning, mulching tomatoes can suppress soil-borne pathogens. When it rains, the mulch will absorb the water droplets and prevent the soil from splashing up onto lower leaves. This also has the effect of keeping the lower parts of your tomatoes looking clean after a heavy rainfall. Also, try disease-resistant varieties.

• Protects the soil. Direct sunlight, wind, and precipitation can all lead to erosion of unprotected soil. With mulch, the soil is protected from these elements. This helps to maintain the important microbiome and structure that exists below the soil’s surface. I leave my mulch in place over the fall and winter months to keep my garden soil protected all year long.
• Confuses pests. Certain pests are said to be confused by reflective or brightly colored mulch. This may not be a top reason to use mulch, but can potentially be an added benefit if you suffer from particular pests.

As if you needed more reason to start mulching your tomatoes, it can also improve garden aesthetics. While this may not be critical to all growers, mulch can keep your garden looking clean and attractive.

Raw soil can be a bit unsightly to some, while a neatly mulched garden is more appealing. This will depend on the type of mulch used, but any uniform material has this effect. It also keeps your plants from getting dirty after a hard rain storm.

Applying Mulch Properly

It is one thing to know which mulch to use for your tomatoes. It is another thing to use that mulch properly. To get the most out of your mulch, be sure to follow these simple rules.

• Apply a thick layer. Mulch won’t suppress weeds if it isn’t thick enough. Apply a layer at least 2-3″ thick with whatever mulch you choose (except black plastic). If you sprinkle a thin layer of straw around your tomatoes, the weed seeds will still germinate and may even be more difficult to remove.
• Allow plants to grow a bit before mulching. Some seeds may germinate underneath a mulch layer, but most won’t. I find it best to transplant started plants into the soil, then mulch around the base. If you are direct sowing, allow the seedlings to emerge and grow for a couple weeks before applying your mulch.
• Fertilize underneath mulching. If you plan to top dress with fertilizer, be sure to pull the mulch back before applying. Fertilizer added on top of wood chips or straw may become tied up with the carbon-rich mulch. Always apply fertilizer directly to the soil’s surface, not on top of your mulch. This is not as important with water-soluble fertilizers.
• Leave mulch in place over the winter. Unless you plan to plant cover crops, it is best to leave your mulch in the garden year round. The benefits will continue even while the garden is empty. When spring comes back around, simply remove the mulch to plant seeds or seedlings, and re-apply it right afterwards.

Most importantly, get started right away! If your tomatoes are un-mulched, then add some now, regardless of the time of year, to start reaping the benefits.

I hope this article helped you decide on the best mulch for tomatoes. There is a reason it is one of my top tips for growing tomatoes!

There are so many great options that are mostly cheap, and often free to use. Let me know what other mulches you have liked using for tomatoes below!

Calvin

Hi, I’m Calvin, creator of Tomato Geek. I have over a decade of gardening experience and I love helping others grow healthy plants!