Best Vegetables for Container Gardening on a Balcony

The short list

The best vegetables for balcony containers are salad greens, radishes, bush beans, chard, beets, peppers, eggplant, bush cucumbers and compact tomatoes. That is close to the list University of Maryland Extension gives for popular container crops: salad greens, peppers, eggplant, tomatoes, beans, chard, beets, radish, squash and cucumbers. Which of them will work on a particular balcony comes down to two measurements, the hours of direct sun and the size of pot you can fit and lift.

Maryland’s advice on varieties applies across the whole list. In catalogs or on seed packets, look for the words “bush” or “dwarf” on the crops you want to grow. Compact plants need less root room and catch less wind.

Start with the hours of sun

Sun decides the crop group before pot size does. Maryland gives two bands: 6 to 8 hours of direct sun for warm-season crops such as tomato, pepper, eggplant and squash, and 3 to 5 hours of direct sun for cool-season crops such as lettuce, spinach and Asian greens.

Other extension services draw the line in the same place. University of New Hampshire Extension states that most vegetables require full sunlight, at least six hours a day. University of Illinois Extension defines full sun as at least six hours of sunlight and partial shade as four to six hours.

Count the hours on your own balcony on a clear day, because a railing, an overhang or the building next door can cut a south-facing spot down to a morning’s worth. A balcony with 3 to 5 hours is suited to greens, and putting a tomato there wastes the largest pot you own. Under 3 hours falls below the range Maryland gives for any vegetable, so look for a brighter spot before buying pots.

Match the pot to the crop

Maryland sorts vegetables into three sizes and gives a minimum volume of growing media and a depth for each.

Crop size	Minimum growing media	Depth	Crops in the group
Small	1 to 3 gallons	4 to 6 inches	Salad greens, spinach, Asian greens, radish, scallions, peas, basil, cilantro, thyme, mint
Medium	4 to 6 gallons	8 to 12 inches	Beans, beets, chard, carrots, cabbage, summer squash, dwarf varieties of pepper, eggplant and tomato, parsley, rosemary
Large	8 to 10 gallons	12 to 16 inches	Tomatoes, pepper, eggplant, cucumber, winter squash

These are generous sizes compared with some other extension tables. For a crop by crop version in gallons and inches of depth, see our pot size chart for vegetables.

Illinois publishes a crop by crop table with smaller containers. It lists one standard tomato in a three gallon container, two pepper plants or one eggplant in a two gallon container, and one cherry or patio tomato in a one gallon container. Both sets of numbers come from university extension services. Neither page explains the gap. A reasonable way to use them is to treat the Illinois figures as the smallest pot a crop can live in and the Maryland figures as the size to aim for when space allows.

Vegetables and varieties that suit pots

The Illinois table also names varieties for each crop. The rows below are taken from it, grouped by the container size it gives.

Crop	Container (Illinois)	Plants per container	Varieties named
Leaf lettuce	One gallon	4 to 6	Green Ice, Salad Bowl, Red Sails, Black Seeded Simpson, Buttercrunch, Oakleaf
Spinach	One gallon	Thin to 1 to 2 inches apart	American Viking, Long Standing, Bloomsdale, Melody
Swiss chard	One gallon	1	Fordhook Giant, Lucullus
Green beans	One gallon	2 to 3	Topcrop, Tendercrop, Derby
Cucumbers	One gallon	2	Salad Bush, Bush Champion, Spacemaster
Cherry and patio tomatoes	One gallon	1	Pixie, Patio
Radishes	Two gallon	Thin to 1 to 2 inches apart	Champion, Comet, Sparkler, White Icicle, Early Scarlet Globe
Carrots	Two gallon	Thin to 2 to 3 inches apart	Little Finger, Danver’s Half Long, Nantes Half Long
Beets	Two gallon	Thin to 2 to 3 inches apart	Ruby Queen
Peppers	Two gallon	2	Lady Bell, Gypsy, Crispy, New Ace, Red Chilli
Eggplant	Two gallon	1	Dusky
Standard tomatoes	Three gallon	1	Jetstar, Celebrity, Super Bush

For a balcony with 3 to 5 hours of sun, leaf lettuce and spinach are the place to start. Both sit in Maryland’s small group, which needs only 4 to 6 inches of depth, so a window box or a shallow trough works.

With 6 to 8 hours, peppers, eggplant, bush cucumbers and tomatoes become possible. A cherry or patio tomato asks for far less pot than a standard one in both sources, which makes it the easier first tomato for a small space.

Vegetables that are harder on a balcony

Maryland names four crops as more challenging for container growing: melons, corn, potatoes and sweet potatoes. Winter squash sits in its large group, with a minimum of 8 to 10 gallons per container, and that is a lot of floor space for one plant.

None of these are impossible. They take more volume per plant than the crops in the tables above, and on a small balcony the same pot planted with peppers or beans is the more practical use of the space.

Choosing containers for a balcony

Any container can work if water can get out of it, and our guide to containers for a balcony vegetable garden compares the materials in detail. Maryland states that all containers need to let extra water drain so that roots do not drown and rot. Beyond that, the material changes how the pot behaves.

Property	What Maryland says	What it means on a balcony
Porous materials: clay, ceramic, concrete, wood	Dry out more quickly than plastic or metal	Better for herbs than for thirsty tomatoes in full sun
Dark colors	Create higher temperatures that could injure young, tender roots	Choose lighter colors for a spot that gets afternoon sun
Plastic not made for outdoor use	Can become brittle from exposure	Buy pots sold for outdoor growing

Weight and wind are the two balcony problems a garden bed never has. Maryland warns that a 20-inch diameter container filled with moist potting mix and plants can weigh 100 pounds. Check what your balcony is rated to carry before adding several pots of that size. The same source notes that tall plants in relatively small, lightweight containers can be blown over or become top-heavy and topple unless they are well anchored, which is one more reason to prefer bush and dwarf varieties.

Drainage water is the third. It can mark and stain concrete and wood decking, and Maryland suggests self-watering containers or plastic saucers to catch it. Saucers also keep runoff from dripping onto the balcony below.

Potting mix, water and fertilizer

Fill containers with potting mix. New Hampshire is direct on the point: garden soil is too heavy for use in containers, and soil substitutes built from peat moss with sand, perlite or vermiculite work very well.

Expect to water often. Maryland notes that some containers will need watering every day when the weather is hot and dry. New Hampshire’s test is to water thoroughly when the mix has dried to a depth of 1/4 inch.

Container vegetables also need regular feeding. Penn State Extension recommends adding a slow-release fertilizer at planting time and reapplying a soluble fertilizer every two to four weeks. New Hampshire starts a dilute liquid feed once a week after the plants have been growing for 3 to 4 weeks. Maryland suggests looking for a fertilizer with a 3-1-2 ratio of nitrogen, phosphorus and potassium. The reasons behind those intervals are in the guide to fertilizing container plants, and at the end of the season the mix can be refreshed by following the steps for reusing old potting soil.