For many people in urban settings, growing tomatoes and edible plants in pots is necessary due to space constraints (or lack of an aread with 6 hours of direct sunlight). This video and post explains the 6 key requirements for growing food in containers or pots.
Benefits of Growing Food in Pots
As noted above, lack of space and lack of 6 hours of sun daily are two major reasons people choose to grow vegetables in pots. A few other benefits include:
- ability to move containers throughout the day to take advantage of shifting sunlight;
- raised surfaces for those with limited mobility or strength to manage tending the plants;
- plants are less accessible to animals who eat the leaves, roots or fruit;
- soil-borne disease problems are reduced or eliminated;
- it is easier to control the watering regime which can help with disease on leaves
- once set up properly, it can save you a bundle of time because you don’t have to constantly weed
A Special Note about Tomatoes
With respect to tomatoes, all of them “can” be grown in pots but “determinate” tomatoes require much less staking and are therefore good candidates for container growing. Smaller tomatoes, like cherry tomatoes are also good choices for pots due to their small size and weight. Click here for details on the best varieties of tomatoes for container growing.
Beyond Tomatoes: Other Vegetables for Container Growing
For other types of vegetables, attention to growing habits will go a long way in making good choices. For example, some varieties of cucumbers and pole beans can be grown successfully in pots, as long as you provide good support for their vining habits.
Small to medium-sized root vegetables like radishes, carrots, turnips, and beets can be grown in containers, as can green onions, peppers, eggplant, and broccoli.
Most herbs are fairly easy to grow in containers, as long as they have access to 6 or more hours/day of direct sunlight.
Salad greens can flourish in shadier areas and do not need large pots, as they have shallow root systems.
When selecting pots for container gardening, there are three main factors to consider.
Selection of Pots
Drainage is arguably the most important consideration. If you’re going to grow edibles in containers, your pot must have good drainage so that your plants do not sit in standing water. Standing water in pots will kill plants, if left in it for too long.
You can also reduce the chances of root rot by putting an inch of gravel in the bottom of the pot to hold excess water away from roots. I know gardeners who put a layer of compostable packing peanuts in the bottom of large containers to provide drainage and reduce the weight of big pots (large heavy pots are difficult to move).
The kind of pot used is also important. You’ll want to keep a few things in mind before you make your choice. Wooden containers (half-barrels, for example) may offer a look, size, and shape that you like, but they will rot over time and need to be replaced.
The porous nature of unglazed terra cotta pots will make it difficult to keep your pots sufficiently watered since water will evaporate through the pot’s surface.
Better choices are pots made of nonporous materials like glazed ceramic, plastic, glass, and metal, though at the risk of sounding like a broken record, don’t forget that good drainage is essential.
Size is the third factor to consider. Most tomatoes require pots that hold at least five gallons of soil or potting medium. Vegetables that remain smaller can obviously do well in smaller pots, though less than one gallon is generally not recommended except for herbs and small salad greens.
A few plants have specific requirements. For example, carrots need to grow in soil that is at least two inches deeper than their mature length, and green beans need to be spaced at least three inches apart.
Soil: Choosing a Growing Medium
Many experts recommend using a “potting soil”for container growing because it drains well and is lighter weight (especially important if your pots are large and require lifting or moving). Using soil from your garden Can introduce soil-borne diseases into your containers.
You can make your own potting mix with equal parts of soil, compost or peat, and either sand, perlite, or vermiculite, but again, be sure to use sterilized soil.
The Planting Stage
If planting seedlings or “starts” plant them so that the level of the soil in the pot from which they’re being transplanted is at the surface of the soil or potting medium in the container.
One exception to this rule is tomatoes, which can nearly always benefit from being planted deeper, so that the first set of leaves (the seed leaves) is below the soil line; this allows the tomatoes to grow additional roots, resulting in more tomatoes.
The Maintenance Stage
A key factor for successful container gardens as the summer wears on is watering. Because the soil in pots can heat up more quickly than soil in the garden and has less overall capacity to hold water, containers generally need to be watered daily during hot weather.
In fact, in especially hot and windy weather, you may need to water more than once a day. Some growers recommend that at least once each week you water deeply enough for water to run through the bottom of the pot, but be sure the excess drains away.
As with gardens, you can help maintain moisture in your pot by putting a layer of mulch on the surface of the soil.
Feeding and fertilizing container plants is essential for plant health and robust production. There are many options for fertilizer. Just be sure you choose a fertilizer that’s specific to the particular vegetable you are growing and then carefully read the directions for the correct amounts, method, and timing of application.
Tomatoes in containers will need fertilizing with lime or epson salts to prevent blossom end rot. See this post to learn all about blossom end rot (the bane of growing tomatoes in pots).