Tomatoes grow great in containers if they have the proper soil to grow in. What do you use? Here are my thoughts on potting soil for tomatoes in containers.
Why Use Potting Soil For Tomatoes In Containers?
The temptation is to just scoop some topsoil into a pot and plant your tomato in that. However, garden soil compacts too much in a container, and your tomato plant will not thrive. If you want the biggest harvest, you need to use potting soil, not garden soil.
Potting Soil Versus Potting Mix
You may hear people refer to potting mix instead of potting soil. Potting soil does contain some garden soil, but a potting mix is soilless. I prefer potting mixes because they hold up better than potting soil. They typically include something that holds water, like sphagnum moss or peat moss, and something that breaks up the structure of the mix, like perlite or vermiculite. Some potting mixes include finely ground bark or other materials, depending on the plants they are intended for. Most soilless potting mixes are sterilized after being mixed, so you know they do not have any diseases that could cause you problems.
Things I Consider When Buying Potting Mixes
There are lots of potting mixes available. Here is what I consider when buying one.
Drainage
Some potting mixes drain very quickly and do not hold much water. These are typically intended for cacti, orchards, and other plants that make do with very little moisture. Other potting mixes can be heavy and hold a lot of water. For a tomato plant, you want a mix somewhere in the middle. It should hold enough water to stay evenly moist between watering, but not so much water that the roots rot.
Intended Function
While you can buy a general potting mix that works for a wide variety of plants, you can also find potting mixes for particular plants. I use a potting mix intended for starting seeds to get my seedlings going in a tray. When I move them to a container like pots or grow bags, I use a potting mix intended for vegetables. There are a few potting mixes specifically for tomatoes, but they can be hard to find and are more expensive than a vegetable potting mix. I am not convinced that they are better enough to justify the expense.
Cost
I would be lying if I said I don’t consider cost, but I try to spend the money for a premium potting mix. Like anything else, you get what you pay for. Buy the best potting mix you can afford. You don’t want to waste time and effort trying to raise tomatoes in a subpar potting mix.
Starting Seeds Versus Growing Tomatoes
The potting mixes for starting seeds and for growing tomatoes are different. Seed-starting mixes are very light and have lots of air space for the fragile new roots to expand into. Growing tomato mixes are more substantial so that the roots can hold tightly to the mix, and the plant won’t be as likely to tip over. As I mentioned, I start my seedlings in a tray with seed starting mix, then move them to a container of their own with vegetable potting mix.
Best Potting Soils For Tomatoes In Containers
1. SUNGRO HORTICULTURE Black Gold® Natural & Organic Potting Mix – Best Overall
SUNGRO HORTICULTURE Black Gold® Natural & Organic Potting Mix is my pick for the best overall potting mix for tomatoes. This potting mix has Canadian sphagnum peat moss, compost, horticultural grade perlite, pumice, or cinders, earthworm castings, silicon, and processed bark. It also has a blend of Endomycorrhizae, fungi that help roots absorb nutrients. The perlite and pumice make the mixture light and resistant to compaction. The potting mix has medium drainage, medium water retention, and medium particle size. Tomato roots can grab the particles and keep them from tipping over as easily, although I would still anchor the pot down. This potting mix is certified organic. It is made in China.
Sungro Horticulture was founded in 1929 and is a leader in soilless potting mixes. Their potting mixes are distributed throughout North America.
SUNGRO HORTICULTURE Black Gold® Natural & Organic Potting Mix has all the right things in it and doesn’t have to be fertilized for the first three months. Most potting mixes have to be fertilized after a month. The addition of beneficial fungi into the mix will help the tomato plant absorb nutrients better.
The peat moss and compost will hold the right amount of water, while the perlite and pumice will create air pockets for the roots to grow in. They also make sure the roots get enough oxygen. The processed bark and earthworm castings add valuable organic matter and will feed your plant as it decomposes. Many people swear by earthworm castings to grow large tomato plants. This potting mix has an NPK ratio of 0.09-0.03-0.03.
At less than $20 for a 16-quart bag, I think this potting mix is not too expensive, especially given the rich premium ingredients. I would really pay attention to the use-by date on this potting mix because the beneficial fungi will begin to die off if the bag is old or gets too hot and dry. Be sure to store any leftover potting mix in a cool, dry place to keep from killing the fungi. A hot garage or shed is not a good place to put the bag. I store mine in the utility room, where it will stay cool in the summer and warm in the winter. Keep it out of reach of your pets and children.
The silicon in the mix is supposed to increase the plant’s resilience. In other words, it helps the plant withstand dry periods, cold, and wind. Of course, you can control the amount of water the plant gets, but not the cold or wind. Wind can dehydrate the soil and hence the plant by increasing evaporation, so water it more if the weather is windy.
Pros:
- Premium ingredients
- Inexpensive
- Organic
Cons:
- Fungi die in the bag after a time
2. Espoma Organic Potting Soil Mix – Best Organic Potting Mix
Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables is my choice for the best organic potting mix. It is ideal for organic gardening. This potting mix contains sphagnum peat moss, compost, perlite, limestone, earthworm castings, alfalfa meal, kelp meal, feather meal, and yucca extract. It also contains a proprietary blend of endo & ecto mycorrhizae. These fungi will last five years from the manufacturer, so check the best-by date when buying the product. You don’t want to get old potting mix. Espoma claims the fungi yield bigger roots, more vigorous plants, more blooms, and help the plant use less water.
The fertilizer in this potting mix lasts about four weeks. After that, you will need to fertilize the tomato plant. Keep the bag in a cool, dry place and keep it sealed to prevent the potting mix from drying out. Keep out of reach of pets and children. If you are not satisfied with how the potting mix performs, Espoma will refund your money.
Espoma was founded in 1929. They have produced fine organic specialty fertilizers and potting mixes since then. Their products are made in the United States and distributed in North America.
Espoma Organic Potting Soil Mix is a good product. I use a lot of Espoma products and trust this brand. I will say that most of the ingredients in this potting mix are fertilizers that will be used up in about four weeks. The peat moss and perlite make up the actual potting mix. The other ingredients will be absorbed by the tomato plant and transformed into juicy tomatoes. This potting mix is fairly expensive, but I think it is worth the extra cost to start my transplants off right. It has a chart on the back telling you how much potting mix you need to fill different-sized pots. A twenty-inch pot needs about 16 quarts to fill it up. I wouldn’t grow a tomato in less than a twenty-inch pot.
This is another product where proper storage matters. If the bag is left unsealed, the potting mix will dry out, and the fungi will die. If the potting mix is in a hot garage or shed the same thing will happen. You can still use the potting mix, but the fungi won’t be there to help your tomato plants absorb the nutrients in fertilizer.
Pros:
- Good fertilizer charge
- Organic
- Contains beneficial fungi
Cons:
- Expensive
3. Burpee, 9 Quarts | Premium Organic Potting Natural Soil Mix – Best Sustainable Potting Mix
Burpee, 9 Quarts | Premium Organic Potting Natural Soil Mix is my choice for the best sustainable potting mix. Instead of peat moss, this potting mix has coconut coir. This is a renewable resource that is the husk of the coconut. It is a byproduct of the coconut industry that would otherwise go to waste. This potting mix also contains Burpee’s organic plant food to feed your tomato plant for up to three months before you have to start fertilizing it. It is organic and can be used in organic gardening. The potting mix is made in the USA and is completely sustainable and renewable. In addition to coconut coir, this contains composted poultry manure and feather meal as sources of nitrogen and phosphorus. Sulfate of potash provides potassium.
Burpee was founded in 1876 by W. Atlee Burpee, a young medical student. He started selling poultry and livestock but switched to seeds in 1877.
I like this potting mix because it doesn’t contain peat moss. There is nothing wrong with peat moss. It holds moisture and gives the roots a medium to grow in. However, peat moss takes thousands of years to form. Cutting peat moss out of the bogs it exists in damages the environment. Much like oil, there is only so much peat moss in the world.
Coconut coir, on the other hand, holds just the right amount of moisture. Unlike cocoa hulls, coconut coir is not poisonous to pets. It literally grows on trees, so it is renewable.
On the other hand, I don’t like that this contains composted poultry manure. I worry that chemicals given to chickens and other poultry might persist and make it into my potting mix. I certainly don’t want them in my food.
The charge of fertilizer in this potting soil lasts up to three months. It has an NPK ratio of 0.12-0.12-0.12. I use this potting mix and don’t fertilize until the tomato plant starts blooming. At that point, I start fertilizing with a fertilizer high in phosphorus and potassium and low in nitrogen.
This potting soil is fairly inexpensive. I would use it if my budget did not run to the Espoma potting mix. It does not have beneficial fungi in it, but I am not sure how crucial those are. Wild fungi will colonize the soil from spores in the air. It just takes longer to build up a beneficial number of fungi that way.
Pros:
- Environmentally friendly
- Uses a renewable resource
- Inexpensive
- Saves fertilizer
Cons:
- No beneficial fungi
- Uses composted poultry manure
4. Espoma SS16 16-Quart Organic Seed Starter Premium Potting Mix – Best Organic Seed Starting Mix
Espoma SS16 16-Quart Organic Seed Starter Premium Potting Mix is my pick for the best organic seed starting mix. I use organic potting mix from starting my seeds through when I am harvesting my tomatoes because I want to use only safe products. This potting mix is mostly peat moss with perlite, limestone to adjust pH and yucca extract. It also contains beneficial fungi. The large quantity of peat moss keeps the seed moist and causes it to germinate. The perlite helps the mix to drain so the seedlings do not dampen off. The beneficial fungi have been discussed at length above. This potting mix is guaranteed to work or your money back.
I use this mix to start my seeds because it has the right mix of materials to help them grow strong and get ready for transplant. It is fairly expensive, but I think it is worth the extra cost because my seeds are started off right. I like that it is organic, so I can buy organically grown seeds and raise them entirely organically. I try to be careful what I eat. The last thing I want is to introduce heavy metals and contaminants from the potting mix I use. If you can’t afford to use this potting mix, try the Jiffy Natural & Organic Seed Starting Soil Mix.
While you want a potting mix with medium-density particles for adult tomato vines, you need fine particles in a seed starting mix. The delicate roots of a new seedling can’t manage medium size particles. The ground peat moss in this potting mix is soft and readily slides aside as the roots grow and expand. The perlite keeps the peat moss from compacting too much and becoming too hard for the roots to navigate. I have been able to grow good tomato seedlings using this seed-starting mix that went on to have lots of tomatoes.
Seed-starting potting mixes like Espoma SS16 16-Quart Organic Seed Starter Premium Potting Mix do not have fertilizer in them. At first, the seedling grows using the energy in the seed. They don’t need fertilizer, and it will burn them up. After the plant has its first true leaves, I water it with a dilute fertilizer solution to give it more energy to grow. Be careful to use a very dilute fertilizer because it is easy to burn the seedling’s delicate roots.
Pros:
- Organic
- Beneficial fungi
Cons:
- Expensive
5. Jiffy Natural & Organic Seed Starting Soil Mix – Best Budget Seed Starting Mix
Jiffy Natural & Organic Seed Starting Soil Mix is my pick as the best budget seed starting mix. It is organic but is cheaper than the Espoma seed starter. This seed starting mix has peat moss, vermiculite, and lime to balance pH. Vermiculite, like perlite, aerates the soil and also absorbs water that it then gradually releases so the seedlings can use it. Peat moss also absorbs water and gradually releases it, in addition to its other good qualities.
Jiffy has been producing innovative products for the professional and home gardeners since the 1950s. They sell their products worldwide.
Jiffy mixes were the first seed starting mix I used. It was what I could afford. The products are good, serviceable mixes, and this one is no exception. I have found that my seedlings grow faster in Espoma seed starting mix, but it is more expensive. If you are just starting out, this is a good starter mix. It contains vermiculite, which is an aluminosilicate clay mineral that is heated. It soaks up three to four times its weight in water and attracts some nutrients, such as calcium, magnesium, potassium, and phosphorous. Perlite, which is in many potting mixes, does not absorb much water but aerates the soil. Because of the extra water absorption, seedlings started in Jiffy Natural & Organic Seed Starting Soil Mix might be slightly more likely to develop damping off, a fungal infection at the soil line that kills seedlings. If you have trouble with that in your seedlings, try the Espoma seed starting mix instead.
Jiffy Natural & Organic Seed Starting Soil Mix does not have any beneficial fungi in it. I am not sure this matters much, although the beneficial fungi might out-compete the bad fungi that cause damping off.
Jiffy makes a lot of peat pots and peat pellets, and this seed starting mix is compatible with those products. I use a tray to start my seedlings, then transplant them into a pot from there. I have found the peat pots and pellets don’t work very well for me, but you may be more successful with them. If you do use a peat pellet or pot, be sure the entire pot is buried in the new pot. Otherwise, the edge of the peat pot will wick moisture away from your plant.
Pros:
- Inexpensive
Cons:
- May be more susceptible to damping off
Best Homemade Potting Mix For Tomatoes
You can make your own potting mix for growing tomatoes. Here is the recipe for a good potting mix.
- Eight gallons of vermiculite or perlite
- Eight gallons of peat moss
- 1 ¼ cups of dolomitic lime
- ½ cup of 20 percent superphosphate (0-20-0)
- 1 cup of 5-10-5 fertilizer
Mixing instructions:
- Mix well.
- Take out the amount you need for today.
- Wet the potting mix in a five-gallon bucket as described below.
- Use the wet mix to pot your tomato plant.
Tips For Using Potting Mix Successfully
Here are some tips to use your potting mix successfully.
- Dry potting mix sheds water. Before using a potting mix, pour the amount you need in a five-gallon bucket and fill the bucket with enough water to cover the mix. Stir the mix until all parts of it are wet.
- Use fresh potting mix for each plant. Reusing potting mix makes it more likely your plant will get soil-borne diseases.
- Buy the best potting mix you can afford. Your plants will thank you.
Final Verdict
SUNGRO HORTICULTURE Black Gold® Natural & Organic Potting Mix is my pick for the best overall potting mix. It has everything you need in one bag. My pick for the best organic potting mix is Espoma Organic Potting Soil Mix – All Natural Potting Mix For All Indoor & Outdoor Containers Including Herbs & Vegetables. I trust the Espoma brand and like this potting mix. Burpee, 9 Quarts | Premium Organic Potting Natural Soil Mix is my choice for the best sustainable potting mix. It uses coconut coir instead of peat moss. Espoma SS16 16-Quart Organic Seed Starter Premium Potting Mix is my pick for the best organic seed starting mix. I use it so my seeds are grown in an organic medium from the start of their life through the end of their life. My pick for the best budget seed starting mix is Jiffy Natural & Organic Seed Starting Soil Mix. You get a lot for not a lot of money.
