How to Create a Container Garden for Edibles in the North Carolina Piedmont

Edibles can be grown in containers in a variety of outdoor spaces: a small apartment balcony, a large deck space, or even a front stoop. People grow edibles for a variety of reasons. You may want to grow tomatoes for a sandwich or lettuce for a salad, or you might be providing herbs, vegetables, and fruit for a family. Regardless of the scope or size of your container garden, selecting the right containers, planting media, and plant combinations are the first steps on the road to success. In this publication you will find ideas to get you started growing your own edibles.


Selecting a container:

Edible plants can be grown in containers that you purchase, build, or recycle. Almost anything will work as long as it has drain-age holes, such as a reclaimed galvanized metal bucket, a discarded wooden dresser drawer, or a bright glazed pot whose color contrasts with the plant’s foliage, flowers, or fruit. Wood, clay, and unglazed ceramic containers will lose moisture more quickly and will therefore require more frequent watering than plastic, metal, fiberglass, or glazed pots. This is also true for small or dark-colored containers. The temperature of the planting media in a metal pot can fluctuate by as much as 30°F between day and night. However, roots can be protected from extremes of heat and cold by lining the pot with bubble wrap or 1-inch-thick foam. Plastic and wood containers can safely remain outside year round, and cedar and redwood containers will last around 10 years without staining or painting. Select a container to provide adequate space for roots. Container size should match the plant’s growth requirements to prevent restricted root growth, which can result in decreased plant growth (for more information on container size requirements for certain edibles, refer to publication AG-748, “Container Garden Planting Calendar for Edibles in the N.C. Piedmont”). The larger the pot, the less frequently it will need to be watered. If larger plants need to be moved indoors for overwintering, it may be best to have them on a rolling platform; a 20-inch-diameter container filled with growing media and lots of water can weigh up to 100 pounds. When plants become larger, they can be more difficult to move.

Selecting Planting Media:

Container planting media can be purchased or homemade, but careful consideration must go into its composition. Otherwise, the media may be too dense and compacted to allow the plants to thrive. Garden soil should not be used because some soils do not drain well (i.e., red piedmont clay), which limits plant roots’ access to air. In addition, garden soils may contain many pests, such as weed seed, disease, or insects. Many soilless mixes are commercially available. These lightweight, pH-adjusted products are free of pests and often contain a nutrient supplement that serves as a good starter fertilizer. Look for planting media certified by the Mulch and Soil Council, the national nonprofit trade association for all producers of horticultural mulches, consumer potting soils, and commercial growing media. Certification ensures that the product label accurately identifies what is in the bag.

Gardeners can make a soil mix from one part compost; one part perlite, vermiculite, or coarse builder’s sand; and one part pasteurized soil or potting soil. In most situations it will be faster, easier, and more precise to purchase a commercial soilless mix. However, if specific needs are present, such as those discussed below, making a custom-made soil mix may be preferable.

  • To prevent the container from blowing down in windy conditions, increase sand (more than one-third of the mixture should be soil and sand) and limit perlite.
  • When growing high-water-use crops (such as tomatoes) without an automatic irrigation system to water them more than once a day, the mixture should include vermiculite and compost to increase its water-holding capacity.
  • For plants that are sensitive to root rot or that prefer dry conditions, such as lavender, rosemary, oregano, and thyme, limit soil and sand to no more than one-third of the total mixture, and include perlite for a blend with more air space.

Selecting Plants

All plants placed in the same container must have similar requirements for light, water, and nutrients. Most warm-season vegetables and fruits do best in full sun, in locations that receive at least six to eight hours of sunlight a day. Some fruits and a few vegetables prefer full sun but will tolerate partial shade during the heat of the day. Most herbs and cool-season vegetables—such as beets, carrots, kale, lettuce, radishes, and spinach—tolerate partial shade, needing only three to five hours of direct sun a day. In the North Carolina piedmont, cool-season plants can be grown from late winter to early spring and again through the fall and early winter. Warm-season plants are generally grown from May through September (for more information on planting dates, refer to “Container Garden Planting Calendar for Edibles in the N.C. Piedmont”). When choosing multiple plants to group in one container, use the information in Tables 1, 2, and 3 to select plants with similar light, water, and nutrient requirements. Selecting plants with closely related needs will ensure that they all thrive in the same conditions.

Most vegetables require consistent and even watering. Apply water directly to the soil, and prevent splashing of soil onto the leaves, which can spread diseases. The majority of vegetables require a moderate amount of fertilization, but a few, including cucumbers, squash, and tomatoes, are heavy feeders that require extra nutrients in order to produce healthy fruit.

Most fruits prefer full sun, with filtered light during the heat of the day. The production of fruit on the plant uses nutrients, so moderate to heavy fertilization is required for a good crop. Many fruits require supplemental phosphorous or potassium, so refer to related extension publications for specific fertilizer recommendations. The majority of herbs tolerate partial shade and prefer low nutrient levels. Some thrive in moist soil, but many taste best when they are allowed to go slightly dry between watering or are kept in a well-drained or dry container medium.

Creating a Successful Container Garden:

Follow these key guidelines to create a successful container garden:

  • Grow edibles on a balcony, deck, or entrance area.
  • Use only containers that have drainage holes.
  • Avoid small or dark-colored containers.
  •  Use planting media, not garden soil, which is too dense and compacts too much.
  • Group plants in a container with other plants that have similar requirements for light, water, and nutrients.

There are many options and opportunities for creating an edible garden that is both functional and aesthetically pleasing. Use color, texture, and differences in size for a striking display. Select plants with similar requirements for light, water, and nutrients, and plant combinations of vegetables, fruits, and herbs in the same container. Keep these principles in mind and reap the benefits that a container garden has to offer.

This is only portions of the entire publication, for more information please refer below.

Source: Kim Richter, Lucy Bradley, Mark Kistler, Julie Sherk