When it comes to cultivating a kitchen garden, many gardeners overlook one easy opportunity: growing vegetables in containers. Even on a small porch or patio, you can create an edible container garden full of fresh produce. There are some tricks to getting a big bounty out of your pots, though. Read on for our best tips.
Best Containers for Growing Vegetables
Before you start planting seedlings or sowing seeds to grow vegetables in containers, you need the right pots. Be sure to pick containers that will work for the space you have and the vegetables you want to grow.
Type of Container
Most vegetables aren't fussy about what type of container they grow in, but there are plenty of other factors that should drive your container choice. Remember that all pots need drainage holes so excess water can escape.
• Material: In general, plants growing in terra-cotta (clay) pots need more attention to watering than in other types of pots, because of the porous nature of the material. Avoid vegetable containers made of treated wood, as that may contain chemical compounds that could be absorbed by your vegetables.
• Weight: Try to choose a lightweight container, especially if you plan on moving your vegetable garden around. Once it's planted, it can get pretty heavy, especially after watering.
• Color: Dark colors absorb heat, so they may make the soil too warm for some vegetable crops in summer, especially in hot areas.
Size and Shape of Container
The type of vegetable you're growing in a container should guide the size of the pot. There are some key things to keep in mind.
• Height and width: Vegetables like lettuce with shallow roots don't need pots as tall as something like tomatoes, which have deep roots. In general, though, pots should be at least 10" wide. Keep in mind that large pots hold more soil and will hold moisture longer, so you don't have to water as much.
•Shape: Feel free to think beyond the typical round flower pot. Half barrels, plastic-lined bushel baskets, and window boxes can work just as well.
• Support: Plants that grow tall or produce vines (like tomatoes and cucumbers) will be more productive if they're grown with a support in the container. Something as simple as a wire cage inserted into the container at planting time will work. Use larger, heavier containers for trellised plants to minimize the risk of tipping.
Best Type of Soil to Use in Vegetable Containers
Vegetables in containers need a potting mix that will allow water to drain well. Like most other container gardens, your vegetables will do best in potting mixes made for containers. Fill the containers so the soil is at least 2-3 inches below the rim (that extra space at the top will give you room to water deeply without overflowing the container). Water the soil just before planting.
How to Plant Vegetables in Containers
Most vegetables have similar needs (full sun and well-drained soil), but it's also good to double-check their needs (and, if you're planting multiple vegetables in one container, make sure those needs are identical). Depending on what types of vegetables you want to grow, you can start seeds in your containers, grow start seeds indoors, then transplant, or purchase starts from a garden center.
• Sow seeds: Sow seeds according to the seed package directions. Because not all seeds will germinate, plant more than you need, then thin the excess later.
• Plant starts or seedlings: If you're transplanting, gently loosen the root ball by tugging lightly at the roots before adding it to your container. Set transplants or starters at the same level they were growing in their pot (except for tomatoes—you can pinch off their lower leaves and plant the stems deeper in the container). Buy plastic tags to help with the identification of each plant.
• Fertilize: Sprinkle a balanced, organic fertilizer in the soil, either before or after planting. Don't over-fertilize; plants will grow too quickly so they'll be more likely to flop over, and the flavor won't be as rich.
• Water: At planting time, water gently but thoroughly to settle the seeds or transplants. Keep the potting soil from drying out by mulching with straw, compost, leaf mold, or a similar material.
Start container garden crops such as beans, corn, carrots, radishes, and spinach from seeds sown directly in the container.
How to Care for Vegetables in Containers
Vegetables in containers will in general have the same requirements as those in the ground. Here's how to keep them thriving:
• Water: Watering is the most important thing to watch for in your vegetable container garden. Inspect your vegetables regularly to make sure the potting mix hasn't dried out by sticking your finger in the soil; if it's dry, it's time to water. Soil in pots dries out more quickly than the ground, so you will likely need to water every few days—or even more often if the weather is hot and dry.
• Check regularly: To keep your vegetable garden its most productive, keep an eye out for weeds and other pests. While plants in containers usually aren't as susceptible to diseases as varieties grown in the ground, you'll still want to watch for problems. Remove or treat any plants that show signs of disease or insect damage.
• Fertilize: Starting about a month after planting, feed your vegetables about once a week with a water-soluble fertilizer, following the package directions.
Make watering your vegetable container garden easier by installing a drip-irrigation system. It can automatically irrigate your vegetables for you.
How to Harvest Container Vegetables
Harvesting is the most satisfying step, and it doesn't take much to get it right. Pick your crops as soon as they reach a size where you will enjoy them. Most vegetables are more productive if you harvest early and often. Letting plants "go to seed" will often cause a drop in fruit set. And when harvesting anything except root crops, it's a good idea to use pruners, scissors, or a knife to remove what you need; if you try to pull off leaves or fruits, you risk damaging the plant and even uprooting it from the container.
Top Vegetables for Containers
Below are the basic instructions for growing a variety of vegetables in containers. Note that the suggested planting instructions are for optimal growth. You can often grow vegetables in smaller containers with acceptable results.
- Beets: Direct seed into a 2- to 5-gallon window box.
- Cabbage: One plant per 5-gallon container. Or with small varieties, one plant per gallon container.
- Carrots: Direct seed into a 2- to 5-gallon deep container. Thin to 3 inches apart.
- Cucumber: Two plants per 5-gallon container. If using vining types, grow on trellis or cage.
- Eggplant: One plant per 5-gallon container.
- Garlic: One clove every 3 inches.
- Green Beans: Sow directly into a 5-gallon window box.
- Kohlrabi: Direct seed into a 5-gallon container. Thin to three plants.
- Lettuce: Direct seed or transplant into 1-gallon or larger container. Thin to 8 inches apart.
- Onion: Direct seed into 1-gallon or large container. Thin to 2 inches between green onions. For bulb onions, thin to 6 inches apart.
- Peas: Direct seed into 5-gallon container. Grow taller varieties on a trellis. Thin to 5 inches apart.
- Pepper: One transplant per 5-gallon container.
- Potatoes: One plant per 2.5-gallon container.
- Radishes: Direct seed into 2-gallon or larger container. Thin to 3 inches apart.
- Spinach: Direct seed into 1-gallon or larger container. Thin to 3 inches apart.
- Summer Squash: Direct seed or transplant, two plants per 5-gallon container.
- Swiss Chard: Transplant or direct seed four plants per 5-gallon container.
- Tomatoes: Transplant one plant per 5-gallon container.
- Winter Squash: Direct seed one plant per 5-gallon container.