Expert Advice on Growing Tomatoes in Containers

Did you know, gardeners plant more tomatoes in the United States than anything else? Tomatoes are the icon of the home garden. And if you’ve ever tasted a homegrown tomato, you know why! Homegrown tomatoes have a rich flavor superior to anything you can find at the grocery store.

If you’re ready to find out what all the fuss is about, use this guide to grow fresh, tasty tomatoes almost anywhere! I’m sharing my best tips of the trade for growing tomatoes in containers so you can learn how to grow tomatoes in your own container garden.

Great Things From Small Spaces

I hear of so many would-be gardeners preventing themselves from having a garden because they only have enough room for a few pots. Let me tell you that you CAN grow food, even tomatoes, with only that much space!

Container gardening is so flexible and can be adapted to almost any space, large or small, even a balcony. Check out my patio gardening video series to learn how to grow lettuce, citrus trees, sweet potatoes, and so much more in containers!

Choosing Great Tomato Varieties for Container Gardens

Determinate and semi-determinate tomato plants are compact and bushy instead of vining and don't need much support. This makes them great for pots, but some indeterminate tomatoes will also thrive in containers!

While some tomato plant varieties are better suited to container gardening than others, you’re not limited to just growing cherry tomatoes or just determinate types (although those are great choices). MIgardener offers a large, diverse collection with over 100 varieties of container-friendly tomato seeds to choose from! You'll be surprised at all the options.

The Best Containers For Growing Tomatoes

Tomatoes have a huge root system and need a lot of rich soil. Choosing the right container is key to growing them successfully!

Tomatoes need a 5-gallon container; anything smaller will restrict their root growth and reduce their productivity. The material the pot is made of is also important. Here are the pros and cons of common container types:

• Plastic Pots - Plastic pots are lightweight, durable, weather-resistant, and often more affordable than other options. The downside is that plastic isn’t very breathable. It can trap excess water (even with drainage holes), leading to root rot and other issues. If you choose plastic, look for food-grade, UV-resistant, BPA, BPS & PVC-free plastics (like these awesome Greenstalk Vertical Planters). Pro-Tip: Pick lightly colored pots to avoid “baked roots.” Lighter pots reflect the sunshine and heat, whereas dark pots absorb it.

• Clay Pots (Terracotta) - Unglazed terracotta pots are breathable and wick away moisture, allowing excess water to leave and the roots to get more oxygen. However, terracotta is very heavy and fragile. It heats up and dries out faster in the summer sun (leading to baked roots) and may freeze and crack in the winter. 

• Wooden Planters - These provide good insulation to keep roots cool, good drainage, and can be customized to your space. Wood requires more maintenance, may be more expensive than other options, and is prone to rot, so use naturally rot-resistant wood like cedar or pine and coat it with Boiled Linseed Oil before using it. Pro-Tip: Don’t use treated wood from the early 2000s or before. 

• Fabric Pots - Fabric grow bags have all the pros without the cons! They are lightweight, breathable, durable, inexpensive, BPA-free, long-lasting, and very easy to move around and store. Grow bags are also better at controlling the internal temperature and water content of the soil than traditional pots, reducing the chances of baked roots and root rot. Plus, they create a healthier root system through air pruning! (Watch the video above to learn about air pruning.)

Creating the Best Potting Mix For Tomatoes

For successful container gardening, it’s important to start with a great potting mix. Use a loose, well-draining potting-specific soil mix, not topsoil or bagged compost. My go-to choices are Pro-Mix high-quality potting soil or my own frugal, homemade potting mix recipe.

To make my DIY potting mix, I use this seed starting mix recipe with coco coir and simply increase the size of the perlite for better drainage and aeration.

Keep in mind that this mix has a neutral pH, and tomatoes like acidic soil with a pH around 5.5. To increase the acidity, add powdered sulfur or try 1/2 cup of coffee or apple cider vinegar mixed into 1/2 gallon of water and water it over the potting mix. 

Step-by-Step Guide to Planting Tomatoes in Pots

Now, let’s get planting!

1. Harden Off Seedlings  - You cannot just take seedlings that have been started indoors and transplant them immediately into pots outdoors, or they will struggle and potentially die. If that is news to you, make sure to read these blog posts to learn how to transplant seedlings and how to properly harden off seedlings in just 5 days!

2. Fill Containers  - Fill your containers with premoistened potting mix. Premoistening helps to reduce transplant shock. Pro-Tip: You know you have the correct amount of moisture in the mix if you can take a handful and squeeze it very hard, but only a few drops of water come out. If no water drips out, add a bit more water.

3. Plant Spacing - Plant one tomato plant per container. Planting multiple tomatoes in a 5-gallon container will stress the plants and prevent them from producing well. 

4. Planting Depth  - Bury tomato seedlings deeply when transplanting them into pots to create a stronger root system. Dig a hole about ⅔ the height of the plant. Remove the leaves and stems from the lower ⅔ of the plant. Bury the seedling, only leaving the top  ⅓ above the soil level. Then, backfill around your plant.

5. Provide Adequate Sunlight  - Tomatoes like sunlight! Placing your containers in a location that gets 8-9 hours of full sun is optimal, but tomatoes can grow with a minimum 5-6 hours of direct sunlight. If you have multiple potted plants, ensure your other plants don’t shade the tomato’s leaves from the sun. Pro-Tip: Because containers tend to dry out more quickly, placing other potted plants in locations where they will shade the tomato's container and root zone is beneficial.

6. Fertilize - Not all potting mixes contain fertilizer, and even if they do, your tomatoes will benefit from additional fertilizing. Use a well-balanced, slow-release fertilizer like Trifecta+ at a ratio of about 3 Tbsp of fertilizer per gallon of mix. Pro-Tip: Fertilize about 25% more when using fabric grow bags than you would with a standard pot. Every part of a fabric pot drains and breathes, so more nutrients are lost. I fertilize heavy feeders like tomatoes about once a month.

7. Consistent Moisture  - Tomatoes need regular watering. Most tomatoes require 1 to 2 inches of water per week, but remember, containers tend to dry out quicker. Check them often and water as needed to keep the soil moist but not soggy.

Advice for Growing Tomatoes in Containers: Pruning & Staking

Almost all tomato varieties will benefit from good support, especially indeterminate tomatoes, which continue to grow all season. Sturdy supports keep tomatoes upright, save space, and help prevent disease by improving air flow.

The best support method for your tomatoes will depend on your container, tomato variety, and growing location. Several vertical gardening options can work well with containers, such as placing your pots at the base of a garden trellis or railing that plants can grow up, setting up vegetable trellis netting, making a DIY tomato cage, or using tomato plant stakes (one in each container).

Indeterminate tomato varieties in pots still need to be pruned, so check out this blog post on how to prune tomato plants if you are growing an indeterminate variety.

Troubleshooting Common Issues

Starting with the right containers, quality potting mix, and correct planting and growing strategies will put you way ahead of the curve when it comes to common tomato-growing problems. You have already done yourself a favor and prevented many of the potential struggles!

But it is still not guaranteed that you will have smooth sailing when growing tomatoes in containers. These resources will help you troubleshoot and correct common issues like tomato blight, blossom end rot, powdery mildew, tomato plant leaves curling, splitting tomatoes, and tomato plant flowers dropping.

For pest problems, I recommend these DIY pest prevention methods and organic pesticides for aphids, spider mites, tomato hornworms, and other pests.