Tomatoes are the Holy Grail for many gardeners. Growing tomatoes in containers can be hugely satisfying or a flat out disaster. Sometimes there is nothing you can do to prevent tomato fail – bad weather, late blight or critter problems. However, there are some things that you can do to improve your chances for tomato success. Tomatoes are not the easiest, but they are my favorite plant to grow. To me, a freshly picked tomato, still warm from the sun, is the closest a taste comes to magic. These tips, in no particular order, can help you have success with growing tomatoes in pots.
Use Really Big Containers
One of the most important things you can do to ensure tomato success is to use a big enough container – the bigger, the better. For one plant (unless it’s a very small tomato variety), you need a pot or container that is at least a square foot – 2 square feet is better. Five-gallon buckets (the ones you get at hardware stores, or for free at restaurants of food factories) are the perfect size for one plant. I use a large size reusable grocery bag, and that’s a perfect size too.
Lots of people suggest growing herbs and other plants in the pot too. Not me. It’s hard enough to give tomatoes the consistent amount of moisture they need without throwing in other plants that will compete for the water.
Also, fill up that large container with a good quality potting soil and make sure you have good drainage.
Water, Water and More Water (But not too Much!)
The key to tomato success is to give your tomato plants a consistent amount of water, which can be the biggest challenge for growing tomatoes in pots. The goal it to keep the soil moist, not wet. Too much water and your plant’s roots will rot. Too little water and your plants will get weak, and your tomatoes will get blossom end rot.
Inconsistent water–too little and then too much water and you will have exploding (or at least cracking) tomatoes. The easiest way to deal with this is to use self-watering containers. Otherwise, you will have to check your tomatoes every day. I often find in the heat of the summer, or if it’s hot and windy, I have to water twice a day.
If you are using conventional containers, and you are getting too much rain, protect your tomatoes by moving them into a sheltered area or cover them – if they are small enough.
Another trick with tomatoes is to, water them in the morning (plants take up and use water more efficiently in the morning). Also, water the soil, not the plant as wet leaves can encourage blight and fungus.
Most people way overestimate the amount of sun they get. So a key to happy and healthy container tomatoes should happen before you ever plant them. When picking where to grow your tomatoes, you will need to accurately figure out a place where they will get enough sun. Tomatoes will be ok with 6+ hours of full sun –which is the bare minimum and 8+ hours is better. Either use a sun calculator or go out and check your tomato containers several times over the day and time how much sun hey are getting. If your plants aren’t getting enough sun, move them to somewhere they will. Also, check throughout your growing season, as the sun moves across the sky, what was once a full sun area could be shaded during a critical part of the day.
Tomatoes also like heat, so don’t put them outside before it gets really warm (nights 50 °F), or be ready to move or protect them from the cold. That said, if it is too hot, tomatoes can fail as well.
Most plants will not thrive if you plant them deeply. However, tomatoes are different. You want to plant your tomatoes deeply so that roots will develop from stems that are underground and your tomatoes will be stronger and healthier. When planting a tomato seedling, dig a hole so that most of your plant is covered by soil (though you will want to make sure you have leaves sticking out of the soil), making sure that you remove all the leaves and branches below the soil line. If your pot isn’t deep enough to sink the tomato deeply, (though it should be if you followed item 1!) you can also lay the plant on its side and bury it that way.