If you can’t grow your tomatoes in raised beds or in the ground, container gardening is a great option. It allows you to grow in smaller spaces and easily move your plants from one place to another.
But, you have an important choice to make when growing tomatoes in pots: which soil is best? In this article, I’ll share our recommendations for the best potting soil for tomatoes.
I’ve included several options to help all gardeners find a suitable option. You’ll find soils made of purely organic ingredients, a peat-free soil option, and even a recipe to make your own DIY potting soil.
Best Potting Soil For Tomatoes
Keep in mind: I’ve only tested a small fraction of the potting soils that are available. We grow tomatoes in the Northeast US, so if you are from another region, your options may differ. However, many of my top choices are available nationally, and most are for sale online as well.
Best overall: Happy Frog
Fox Farm is a soil and fertilizer company known for their premium products. While it is not the least expensive on this list, Happy Frog soil is consistently great for getting amazing results from our tomato plants.
One concern you may have with Fox Farm potting soils is that they are not listed as OMRI organic. I reached out to their customer support team, and Fox Farm got back to me with this message:
“While our potting soils do not carry OMRI or CDFA organic certification, we can assure you that it is free of synthetic fertilizers or pesticides.” – Fox Farm Product Support Specialist
The high-quality ingredients in Fox Farm are based on organic matter like aged forest products, sphagnum peat moss, earthworm castings, bat guano, oyster shell, and lime. These act as a slow-release fertilizer.
What makes Happy Frog particularly great for tomatoes is the guaranteed analysis. There is 1.00% calcium in this soil mix, which proves critical for healthy fruit development. With calcium in your potting soil, your tomatoes are unlikely to end up with blossom end rot.
This combination leads to the best results we have seen in our potted plants. Fox Farm soil is great for heavy feeders like tomatoes, and can feed plants for 2-3 months before requiring additional fertilizer. There is no need for soil amendments, as all the essential nutrients for tomato growth are right there in the soil from the start.
Later in the season, we will apply an all-purpose fertilizer, such as Fox Farm’s own Tiger Bloom, or Miracle Gro Organics. This will boost plant growth and help keep your indeterminate tomatoes producing right into the frost.
To me, Happy Frog is an ideal potting mix that can be re-used for several seasons. We have had nothing but healthy tomato plants, so try it here (or shop your local garden center for better pricing).
Best organic: Miracle-Gro Performance Organics
If you are looking for an officially labeled OMRI organic potting soil, this may be for you. The natural ingredients in Miracle Gro Performance Organics soil are made up of peat moss, forest products, perlite, compost, feather meal, soybean meal, and bone meal.
The organic fertilizer used in this soil works well to feed tomatoes for up to 3 months, though we have seen it run out of steam a bit sooner than Fox Farm. This is no surprise, as it contains 36% less nitrogen, 90% less phosphate, and 40% less potassium than Happy Frog (per the guaranteed analysis on the bags).
While this potting soil does not have a guaranteed quantity of calcium, it does contain bone meal. This product contains calcium, nitrogen, and phosphorus, so rest assured that your tomatoes will get the calcium they need.
Still, Performance Organics can hold its own. It has plenty of soil fertility, good water retention, and has grown us some healthy tomatoes. Like most potting soils, this can also be reused for many seasons. If you want a 100% organic potting soil for your tomatoes, Miracle Gro Performance Organics is a good choice.
Best budget: Miracle-Gro Potting Mix
If budget is on your mind, then classic Miracle Gro potting mix will deliver results. While it is non-organic, you can’t deny that it grows healthy plants.
The ingredients are based primarily on peat moss, perlite, and slow-release fertilizer pellets. This potting mix also has the boldest claim of them all, “feeds up to 6 months” and “grows plants twice as big!”
There is an asterisk next to that last claim, adding “when compared to un-fed plants.” Sure, if your plants don’t have nutrients, they won’t grow as big. But I have to admit, if you grow tomatoes in this potting mix, you will see results.
However, we found in our testing that this potting mix required much more pre-moistening. Otherwise, the soil can be hydrophobic and difficult to water. So, before planting, always wet and mix thoroughly until it is evenly damp.
Most garden centers in North America should carry this popular potting soil, and it is usually one of the most affordable options. Keep an eye on your tomatoes for any nutrient deficiency as the plants grow larger and amend with fertilizer as needed.
Best soil mix (Homemade):
If you grow a lot of tomatoes or other veggies, you may want to make your own potting mix from scratch. In large enough quantities, you can save a few dollars by making your own. This is especially true if you have homemade compost available to use!
There are many different ratios that are recommended for the perfect container mix recipe. We’ll keep it simple:
- 1/2 peat moss
- 1/4 perlite
- 1/4 compost
Peat moss is the main ingredient in the potting soil’s mentioned above. It is also available in bulk for relatively cheap. It is often dry and compressed, making it very dusty when mixing – wear a mask!
Peat moss is important for nutrient and water retention in your potting soil. However, it can also become hydrophobic if it is dried out, so always pre-moisten your potting mix before planting.
Perlite is used for aeration and drainage. This is a natural material made of volcanic glass. It is heated to create a lightweight material that has very high water-holding capacity. It also helps prevent soil compaction over time.
Compost is the secret ingredient that will take your potting soil to the next level. This nutrient-rich material can be made at home in your own backyard, and will feed your container tomatoes. Use compost with a wide variety of ingredients for the best results.
These 3 ingredients are enough to grow healthy tomatoes in pots. For the best price, shop at home improvement stores, garden centers, or local feed supply stores.
If you want to get fancy, here are a few other ingredients you can add to your homemade potting soil:
- Bone meal. This adds slow-release calcium, along with additional nitrogen and phosphorus. Don’t add too much, as a little goes a long way (follow the instructions on the packaging where applicable).
- Worm castings. Worm castings are great for a slow and gentle feed. It also improves the soil tilth, making it a better environment for the roots of the plant.
- Slow release fertilizer. Slow release fertilizers are easy to use, as they provide everything a tomato plant needs to grow well. From nitrogen, phosphorus, and potassium, to calcium, magnesium and beneficial bacteria. I have had great results adding Espoma Garden Tone to our gardens.
Making your own potting soil for growing tomatoes is not always the most economical choice (we still have over 2 cubic feed of peat moss that we haven’t yet used). However, if you’re growing dozens of plants in containers, it may be a good idea!
Best peat-free option: Organic Mechanics
Peat moss is the primary ingredient in all of the major potting mixes in North America. Peat is a natural resource that is harvested for use in bagged potting soil. So, if you would rather not rely on a potentially non-renewable resource like peat moss, there are other options.
Organic Mechanic is a peat-free brand that is committed to sustainability. Instead of peat, their potting soil contains forest products and coconut husk fibers. Coco coir is another ingredient that is commonly used as a peat moss alternative, and is a by-product of the coconut industry.
The UK bans the sale of peat in order to protect their peatlands. While there is more natural peat available in Canada than in the Europe, it is still a natural material that is harvested for potting soil.
Ideal Container Size For Tomatoes
As we’ve established, tomatoes are heavy feeders. This means they can benefit from more soil than many other garden veggies. So, what is the best pot size for growing tomatoes?
For best results, grow tomatoes in a 5-10 gallon container, or pots with a 14-16″ diameter. If you are growing large tomato varieties (such as beefsteaks), then lead towards a bigger pot.
Cherry tomatoes are still huge plants, but the smaller fruit size is more forgiving. Either way, a large container size is the best way to ensure your plants can develop a large, resilient root system.
Note: Some larger containers are made for house plants, so make sure the pot you choose has drainage holes. If it doesn’t, it is easy to drill a few holes in the bottom to allow excess water to exit.
Getting The Most Out Of Your Tomatoes
Now, for a few tips when growing tomatoes in containers. These plants are fast-growing and aggressive, so it is good to have a plan going into the growing season!
- Plant tomatoes deep. When transplanting into large pots, dig a deep hole for your seedlings. Bury the main stem of your tomatoes by at least a few inches. The plant will form more roots and will establish more quickly.
- Use proper watering technique. Tomato plants need regular, even watering. In containers, it is best to simply keep the soil moist at all times. Since potting soil drains well, it is difficult to over-water tomatoes in pots. Avoid drought by watering whenever the first few inches of soil dries out.
- Provide support (tomato cage). Tomatoes are large, sprawling plants. Place a tomato cage in your container right after transplanting (or even before). If you wait too long, your plants may grow too large to get the cage around them without causing damage.
- Give them plenty of sun. Tomatoes are warmth and sun-loving plants, so place your pots in the sunniest location possible. Full sun means 6-8+ hours of direct sunlight, every day. This will yield the biggest harvest and most delicious tomatoes.
- Spacing and air flow. Good air circulation is critical for growing healthy tomato plants. Keep your plants spaced apart by at least 2′, and prune away any overly-dense foliage. You should be able to see “through” your plants during the whole growing season. This helps avoid fungal diseases as the plants mature.
My main piece of advice is to keep an eye on watering. Potted plants tend to dry out much more quickly than in-ground garden plots. This is especially true for grow bags. You can add mulch to your potting soil to help retain some moisture, but they will likely need more watering regardless.
Otherwise, your potted tomatoes should grow exceptionally well with the right care and attention!
I hope this article helps you determine the best potting soil for tomatoes. There are countless options, and availability does vary based on your location. So, keep an open mind and try what is available to you to learn more for yourself!