Container Vegetables That Thrive

6 min read · Reviewed August 15, 2026 · Garden Planner editorial team (pending independent horticultural review)

Size is everything

Undersized pots are the commonest failure. Minimums from the plant pages: tomato 20 L (40 cm deep), pepper and eggplant 15–20 L, zucchini 40 L, potatoes 40 L bag, bush beans and lettuce 5–10 L, basil and chives 3–5 L, strawberry 5 L per plant, blueberry 40 L of ericaceous mix, mint 10 L (always a container). Bigger is easier: more water reserve, cooler roots.

Mix, drainage, feeding

Use potting mix, not garden soil, which compacts and drains badly in a pot. Every container needs drainage holes. Nutrients wash out with watering, so feed weekly at half strength once plants are established, or mix a slow-release organic fertiliser into the top layer.

Watering

A 20 L pot with a mature tomato can need watering every day in summer and twice on hot days. Water until it runs from the base. Drip emitters on a timer turn container growing from a chore into a routine. Mulch the surface.

Support

Cages for tomatoes, a small stake for peppers, a teepee for pole beans (30 L container, 4–6 plants). Put supports in at planting.

What works

Tomatoes (determinate or compact cordon), peppers, eggplant, bush beans, lettuce and leafy greens, radishes, carrots (short cultivars), beets, basil and all the Mediterranean herbs, strawberries, dwarf blueberries, potatoes in bags, chard, kale.

What does not

Corn (needs a block for pollination), pumpkins and most winter squash, asparagus, rhubarb, Brussels sprouts, cauliflower (too unforgiving), parsnips.

Companion planting in pots

Space is the limit. A tomato and a basil share a 40 L container comfortably; a tomato and a pepper do not. The planner’s container mode uses volume and depth instead of a grid and checks each plant’s minimum.