Growing Vegetables in Containers

Container gardening is a popular option for many gardeners and in today’s session, Master Gardener Nancy Louwman discusses how to do just that!

Why Containers?

Those with limited access to garden space may find containers a satisfying way to nurture a green thumb. Pots can be located on balconies, patios and decks or anywhere with access to light, water and warmth. Edibles can be started early in the season to prolong the harvest. Containers can be moved around if necessary, and efficiently (although frequently) watered.  The soil used in container gardening may reduce soil borne diseases and pests and it is easier to control the nutrients and pH or acidity of the growing medium in a container.

Photo credit: Nancy Louwman

Choice of Container

There are several considerations when selecting a container for growing vegetables. Clay, metal or plastic pots, fabric bags or wooden materials will all suffice and each has merits. Plastic pots are a popular, lightweight and affordable choice but Nancy cautions to check that only food grade plastics are used.  All plastics leach chemicals, and even more so when exposed to hot sun.

Whatever the choice of material, the container should be large enough to support the size of the plants once they reach maturity,  Tomatoes for example, will do best in a 5 gallon pot, peppers in a 3 gallon one and smaller plants such as lettuce may be fine in a shallower tray. The larger the pot, the more soil and thus moisture it will hold. To ensure proper drainage there should be a hole in the bottom of the pot, which may be covered with pot shards to prevent it from becoming clogged.

Swiss chard. Photo credit:

Planting Medium

Garden soil is too dense for containers; it is easily compacted, which does not support healthy root growth. You can make your own potting medium by combining 1/3 compost, 1/3 peat moss or coconut coir (preferable), and 1/3 perlite or vermiculite. Some prefer to avoid using peat moss as it is harvested from peat bogs, releasing carbon into the atmosphere. The addition of dolomite lime to the mix will raise the pH to about 7.0 which is ideal for many vegetables. To reduce the large amount of soil that would be needed, Nancy also adds brown organic material such as leaves and sticks to the bottom of the pot before adding soil.

There are also many commercial potting mixes available, some with formulations specifically for vegetables and herbs. Organic is always the best choice.


East and south placement of pots is best, with protection from the late day western sun. Ensure taller plants are placed behind shorter ones so that all receive sun exposure.

Pots can sit on metal feet or concrete blocks if they are to be placed on a wooden deck. A tray or saucer beneath will catch excess water which can then be taken up by the plant as it is needed.

Watering and Fertilizing

Nancy stressed the importance of paying attention to watering since container grown plants will dry out more quickly than those in a garden bed.  Because clay pots are porous, they will dry more quickly than plastic.

Water plants deeply, which, depending on the plant and the weather conditions, could be twice a day!  Tomatoes for example, when fruiting, require copious amounts of water. Do not let the soil dry out nor become waterlogged, a potential problem in plastic pots since these do not “breathe”. Inconsistent watering may cause blossom end rot or fruit splitting.

Nancy uses a time-release fertilizer at planting and every two weeks thereafter, and recommends a soluble organic formulation. A spade full of manure for large pots and heavy crops will also do the trick!  

Photo credit:

What to Grow

The choice of vegetables to grow is virtually unlimited. Try varieties specifically marketed for containers or small spaces, such as those labeled “Micro”, “Spacemaster”, “Dwarf” or “Compact”.  Some of Nancy’s suggestions include:

  • Tomatoes – try a determinant (or bush) variety, which has a fixed size at maturity
  • Pole beans – add a structure for these to climb, which makes great use of vertical space
  • Cucumbers – plant a bush variety rather than a climbing one. E.g. Dar, Miniature White, Bush Slicer, Spacemaster
  • Eggplant – these like heat, especially on their roots and will need staking once their heavy fruit are set.  Try Little Fingers, Rosita, Listada de Gandia
  • Peppers – prefer daytime heat and warm nights. Mini Belle, Jalapeno, Shishito are suggested
  • Squash – Ronde de Nice, Gold Rush, Peter Pan, Sundance
  • Greens – lettuce, kale, mustard and arugula or whatever you enjoy eating!
  • Herbs – oregano, parsley, sage and thyme or others that you use frequently
  • Carrots, potatoes – with a deep enough container even root crops can be a success.

Companion plantings can be added to containers and some, such as nasturtiums  (also edible) will provide a brilliant splash of summer colour.  Herbs are also fabulous companion plants.

Borage. Photo credit: Nancy Louwman

Container gardening is a great way to enjoy the benefits of fresh vegetables at your doorstep!