If your inner desire to grow vegetables and herbs is much larger than your outside space, then container vegetable gardening could be the solution for you. You’d be in good company, as the trends in healthy eating and urban living are merging to bring more containers of edible plants to windows, balconies, patios, decks and doorsteps -- wherever there’s a sunny spot.
Even if you have plenty of yard for a traditional vegetable plot, many gardeners prefer the convenience of working within a smaller space that’s easier to manage and control, especially if you’re just starting out. While most of the basic principles of vegetable gardening and organic gardening apply to growing in containers, there are a few twists to watch out for. Here are some tips for getting started with vegetable container gardening:
Vegetables and herbs usually require full sun, more than six hours of sun a day -- or partial shade, three to six hours of morning or early afternoon sunlight a day. Most fruit bearing vegetables such as tomatoes, peppers, cucumbers, squash and eggplant require full sun. Leafy vegetables such as lettuce, cabbage, collards, mustard greens, spinach and parsley can tolerate more shady locations compared to the root vegetables such as turnips, beets, radishes, carrots, and onions. Most herbs can perform well in full sun and partial shade.
Keep in mind that shade from overhangs, buildings or furniture will reduce the amount of sun a container receives. While you can move containers around, it’s best to settle on a good spot with plenty of sun.
The best vegetables for container gardening are those that need less space – especially the dwarf or determinate types, often labeled as a bush variety because they don’t continue growing at length throughout the season. Tomatoes, cucumbers, strawberries, peas and beans are just a few examples of plants that can be either determinate or indeterminate. You can start from seeds or transplants, and you’ll find height and size information on most seed packages and plant labels.
You can use just about any type of container, from ceramic and plastic pots to reusable grocery bags and bushel baskets. The most important factor is good drainage, ideally quarter-inch holes every 2 to 3 inches on the bottom. Also, keep in mind that clay pots are porous and dry out very quickly, which may require more watering. Since you’re growing food, make sure the container material is non-toxic. If it’s plastic, check that it’s food grade.
Container size should be matched to plant size at maturity, root depth and the plant density (number of plants per container). This chart shows suggested plants for container sizes. Also, if you want to be able to move the container, take weight into consideration when choosing the material and size.
It’s best to use potting mix instead of soil in vegetable container gardening because it’s light, disease-free, weed seed-free, and has good drainage. Some potting mixes have pre-mixed plant nutrients, so it’s important to read the label instructions to know how long the nutrients will support plant growth before you should start applying fertilizers. You can purchase commercial potting mix, including those for organic gardening, or make your own. Mix equal parts peat moss and perlite, a non-toxic, lightweight soil additive.
Fill the container with the potting mix, but not to the brim. Water the container until water drips from the holes in the bottom of the container.
Plant seeds or transplants based on the size calculations you made when you chose your plants and containers. You plant transplants the same way they would be planted in the ground: Spread the roots, cover them with potting mix and firm the mix around the roots. Water immediately. Move the containers to the right location based on the plants’ sunlight requirements.
If your potting mix doesn’t contain fertilizers, add the recommended amount according to the label instructions. Choose an organic granular or liquid fertilizer based on your preference. If you’re using a granular fertilizer avoid going overboard, as even natural fertilizers can lead to problems such as nutrient deficiencies, pH imbalance and fertilizer “burn” if over-applied. Follow label instructions for amount and frequency. While it’s harder to damage plants by over applying organic liquid fertilizer, using too much can lead to a strain on your budget.
Don’t fertilize your plants when they’re wilting or showing signs of heat stress. Water them first, a few hours before fertilizing.
Plants grown in containers need more frequent watering than in traditional gardens because they dry out faster. Water container plants daily to provide enough moisture for healthy growth. Apply enough water to reach the bottom of the container, allowing the excess to drain out through the drainage holes. Avoid getting the leaves wet while watering, as this can encourage disease. Try not to let containers dry out completely between watering, as this will lead to flower and fruit drop. Don’t over water the plants, either, because this can cause the container to be waterlogged, which deprives roots of oxygen and leads to poor growth and even eventually kill the plants.
While container plants are just as vulnerable to insect pests and diseases as those in the ground, the same principles for organic vegetable garden pest control and disease control apply. Inspect your plants periodically for insect pests and disease. Watch out for pests that commonly attack vegetables and herbs, such as aphids, spider mites and white flies. Keep in mind that overwatering plants can lead to damping off disease. While your best defense against pests and disease is to promote healthy plants with regular watering and care, it’s a good idea to be prepared to apply treatment. Look for formulas approved for organic gardening, such as EARTH’s ALLY insect and disease control products. While these are easy to use, you should always be sure to read and follow the label instructions, even with natural products.
One of the main advantages of container gardening is it’s easy to start on a small scale and try out different plants and locations. The pepper plant isn’t looking so good in that corner? Maybe it will thrive over by the back door where it will get more sun. Many gardeners find working with a more defined space is easier to manage, especially when it comes to fighting weeds. Others like to give their backs a break by putting containers on tables, platforms or stools. The best part is that with container gardens, even the most space constrained gardener can usually find a way to enjoy growing their own fresh vegetables or herbs. Want to know more? Check out this guide to container gardening from the University of Illinois Extension Service.