How do I grow vegetables in pots?

Which vegetables actually work in containers, what size pot each needs, and why container growing needs more water and feed than ground growing.

Difficulty: beginner
Time: 3 days
Read: 3 min

Short answer

Use bigger pots than you think — most vegetables want at least 20–30 litres — with drainage holes and a peat-free multipurpose compost. Container plants need watering far more often than ground plants, and feeding from about six weeks, because they exhaust the compost's nutrients.

Container growing works well for a surprising range of vegetables, and the constraints are simple: root volume, water and nutrients. Compost holds nutrients for roughly six weeks and dries out in a day in summer, so the two failure modes are almost always underfeeding and underwatering.

What you'll need

Pots of at least 20 litres for most crops
Peat-free multipurpose compost
Liquid feed (tomato feed for fruiting crops)
Watering can
Pot feet or a saucer (optional)

Step by step

Choose crops that suit containers: salad leaves, radish, herbs, chillies, tomatoes, beans, potatoes, courgettes.Avoid anything with a long taproot or a very large spread — parsnips and sweetcorn are poor container crops.
Use the largest pot you reasonably can.Salad leaves manage in 10 litres; tomatoes, courgettes and potatoes want 30 litres or more. Bigger pots dry out more slowly, which matters more than anything else.
Check the pot has drainage holes and raise it slightly off the ground.Waterlogged compost kills roots. A pot sitting flat on paving can't drain properly.
Fill with peat-free multipurpose compost, not garden soil.Garden soil compacts in a pot, drains badly and brings weed seeds and pests.
Water regularly and check daily in summer.A pot in full sun can dry out in a single day. Push a finger in rather than judging by the surface.
Start feeding after about six weeks.Multipurpose compost contains roughly six weeks of nutrients. After that the plant depends entirely on you.
Use a high-potash feed for fruiting crops once flowering starts.Tomato feed works for tomatoes, chillies, courgettes and beans. High nitrogen before that, high potash after.
Group pots together and mulch the surface to reduce drying.Grouping raises humidity around them; a mulch of compost or bark cuts surface evaporation noticeably.

Tips

Self-watering containers with a reservoir make a real difference for anyone who can't water daily in summer.
Terracotta is porous and dries much faster than plastic or glazed pots. Attractive, but more work.
Salad leaves are the highest-value container crop — cut-and-come-again varieties give weeks of harvest from one sowing and are expensive to buy.
Reuse compost for a second season by refreshing it with fresh compost and a slow-release feed, rather than replacing it entirely.

Common mistakes

Pots too small — Limited root volume and rapid drying. This is the main reason container vegetables underperform.
Using garden soil — It compacts, drains poorly in a container, and carries weed seeds and pests.
Not feeding after six weeks — Compost nutrients run out. Plants stall exactly when they should be producing.
No drainage or a pot sitting flat on paving — Waterlogging kills roots as effectively as drought.

Questions people ask

What size pot do I need?

At least 20–30 litres for most vegetables; 10 litres is enough for salad leaves and herbs. Bigger is genuinely better, mainly because larger volumes of compost dry out more slowly.

How often do I need to water containers?

Daily in summer for anything in full sun, and check by pushing a finger into the compost rather than judging by the surface. Larger pots and mulching both reduce the frequency.