Container Gardening for the Urban Farmer

Foods are best when they are freshest, and you can’t get more fresh than reaching out the kitchen window to pick them yourself. If you don’t have a garden plot, turn a sunny windowsill into an herb garden or grow a pot of peppers on your patio. Many plants grow well in containers, from salad greens to strawberries, so apartment-dwellers take note. You can grow fresh food in small spaces.

Plant Picking

Your local farmers’ market or nursery can tell you which plants are best suited to growing conditions in your area. In general, plants that grow best in containers include chard, fennel, garlic, lettuce, leek, onion, pepper, radish, salad greens, shallot, strawberry and tomato. Herbs like basil, chive, cilantro, marjoram, mint, rosemary, sage and thyme also grow well in pots, as do edible flowers like nasturtium, borage, pansy and calendula.

Dwarf varieties of beans, beets, carrots, parsnips and peas can be good container candidates because their roots do not grow as deep as the traditional varieties. Trailing plants like cucumbers, peas, summer squash and zucchini usually take up a lot of space, but if you train vines and tendrils to climb up stakes, trellises or walls, it is possible to grow them in containers. Aside from strawberries, fruit is more difficult to grow in small spaces because even dwarf varieties usually require fifteen-gallon pots and a warm climate, as well as pollination and pruning expertise.

Seeds or Starts

You can buy plants that have been started in a nursery (known as "starts") or germinate them yourself. For container gardens, some plants are best bought as starts because they can be difficult to germinate or because they need to be germinated in the fall for a summer harvest. These include lavender, mint, peppers, rosemary, sage, strawberries, thyme and tomatoes.

Other plants are easily germinated from seed within a week or two under the right conditions. Use a covered seed-starting tray as a miniature greenhouse and keep the seeds moist until they sprout. Arugula, beet, calendula, carrot, chard, cilantro, dandelion, lettuce, marjoram, nasturtium, pansy and savory are good choices if you want to start your plants from seed. Additionally, garlic can be grown from an organic peeled clove planted in soil.

When it comes to containers, different plants require different depths. Plants that only require four inches of dirt include basil, chives, cilantro, most lettuces, radishes and marjoram. Calendula, garlic, mint, mustard greens, nasturtium, savory, shallots and thyme need a pot at least six inches deep. If your container is eight inches or deeper, you can plant chard, lavender, peppers, rosemary, sage, strawberries and tomatoes.

Terra cotta pots are popular choices for container gardening. They are inexpensive, easy to find and available in many sizes, shapes and colors. Terra cotta is made from clay, so unlike metal and plastic pots, their porosity allows oxygen and moisture to pass through the container. They may require more frequent watering, but over-watering and root rot are less likely. Because terra cotta is heavy, these pots provide good stability and are less likely to tip over in windy conditions. If they crack, use a hammer to break them up for drainage pieces.

Although plant pots work perfectly, some opt for more creative container options such as old boxes, buckets, crates, drawers, tubs or half barrels. As long as the receptacle won’t rust and has drainage holes, or you can make some, it can be used for gardening. All containers should be cleaned with biodegradable soap and wiped out with a dilute hydrogen peroxide solution at the end of each growing season and again before planting.

Dirty Details

Soil and drainage materials will be the most important factors in the health of your plants’ roots and the success of your container garden. Roots require certain amounts of moisture, air and nutrients to support foliage and flowers, so treat them well. Dirt from outdoor gardens doesn’t work well in containers, so buy the potting soil and plant food best suited to what you want to grow. Most plants grow well in general-purpose potting soil, but some need more acidic soils, so check before you plant. Rocks, terra cotta pieces and seashells all make good drainage materials for the bottom of the pot. They will keep excess water away from roots and allow air to circulate.

If you put multiple plants in the same pot, choose ones that have similar water, soil and sunlight requirements and space them four to six inches apart. Plants that need full sun include basil, oregano, peppers, rosemary, sage, thyme and tomatoes. Light shade is better for chard, garlic, leeks, lettuce, radishes, spinach and other salad greens. Mint likes moist and shady conditions, and it should always be planted in its own container because it can easily crowd out other plants.

Like all of us, plants need food, water, air and sunlight. When you satisfy their basic requirements, whether they grow on a garden plot or inside a pot, you will be rewarded with a healthy bounty.