Small Space, Real Harvest

You do not need an allotment, or even a garden, to grow something genuinely worth eating. A sunny doorstep, a balcony or a few steps by the back door will happily produce cut-and-come-again salad leaves, a handful of radishes a week and more cherry tomatoes than you can reasonably use in August. Containers give you control over compost, drainage and pests, and they warm up faster in spring than open ground, which means an earlier start and a longer picking season. The trick is choosing the right crops and giving them slightly more attention than a border would need.

Pick Crops That Earn Their Space

Not everything suits a pot. Anything with a deep taproot, or that needs a metre of room, will sulk. The reliable performers are fast, compact and generous:

• Salad leaves. Loose-leaf lettuce, rocket, mizuna and mustard greens are the best value of all. Sow thickly, cut the whole lot at about 8cm tall, and it regrows two or three times. A 30cm pot gives you a bowlful a week.
• Radishes. Ready in three to four weeks from sowing, which makes them perfect for impatient growers and for filling gaps. Sow little and often rather than all at once.
• Cherry tomatoes. Bush or "tumbling" varieties are far easier in pots than cordon types, needing no staking or pinching out. One plant per 30–35cm pot, and expect a couple of handfuls a week from late July.
• Herbs. Basil, parsley, coriander and chives all thrive in containers and cost a fortune to buy fresh. Basil in particular loves a warm, sheltered spot.
• Spring onions. Slow but steady, and you can pull them young as needed. A scattering in the gaps between other pots is space well used.

Pots, Compost and the Right Spot

Size matters more than style. Aim for a minimum of 25cm depth for salad and herbs, and 30cm or more for tomatoes. Terracotta dries out quickly and can crack in a hard frost; glazed ceramic, plastic and fabric grow bags all hold moisture better. Whatever you choose, drainage holes are non-negotiable — a pot without them is a bucket, and roots will rot in a wet June.

Fill with a peat-free multipurpose compost, and mix in a generous handful of slow-release feed if you are planting long-term crops. Do not be tempted to use garden soil; it compacts in pots, drains badly and brings weeds with it.

Positioning is where most container crops are won or lost. Salad leaves and herbs will manage in light shade, but tomatoes and radishes want sun — six hours a day at minimum. A south- or west-facing wall is ideal, and the reflected warmth will push tomatoes on nicely. Do bear weight in mind on balconies: saturated compost is heavy, so cluster pots over load-bearing points rather than the outer edge, and check your lease if you are unsure.

Sowing: A Rolling Schedule Rather Than One Big Push

The single most useful habit is to sow small amounts every two to three weeks from March through to August. This gives you a continuous supply instead of a glut followed by nothing.

• March–April: start salad leaves and radishes under cover or on a warm windowsill, then move them out once nights are above about 7°C.
• Late April–May: sow radishes and salad directly into their final pots outdoors. Start tomato plants indoors and plant them out once the risk of frost has passed.
• June–July: keep resowing salad and radish. Shade newly emerged seedlings on very hot days or they will bolt.
• August: a final sowing of winter-hardy salad leaves will crop into autumn if given some shelter.

Thin seedlings ruthlessly. It feels wasteful, but crowded plants never reach a decent size, and radishes in particular will not swell if they are touching.

Watering and Feeding: Where Most Pots Fail

Container plants rely entirely on you. In summer, a tomato in a pot may need watering twice a day, and missing one will cause split fruit and blossom end rot. Water in the morning where you can, aiming at the compost rather than the leaves, and water until it runs out of the base.

A few practical habits make life easier: group pots together to shade one another, stand them on saucers or trays in high summer, and consider a self-watering container if you are out at work all day. A layer of gravel or cocoa shell on the surface slows evaporation and keeps compost off your leaves.

Feeding starts when the plants do. Salad leaves and herbs need little beyond good compost. Tomatoes are hungry — begin a high-potash tomato feed weekly once the first flowers set fruit, and stop when the plant stops producing.

Pests, Problems and the Picking

Aphids and whitefly are the usual invaders, particularly on tomatoes. Check the undersides of leaves weekly and squirt them off with water before numbers build. Cabbage white butterflies will find your rocket, so fine netting helps if you are prepared to fuss. Slugs and snails will climb pots quite happily, so clear the ground beneath them.

On the whole, though, containers suffer far less than open ground. There is no clubroot, no carrot fly, and you can refresh tired compost each season rather than rotating crops.

Harvest little and often — this is the reward for all of it. Cut salad leaves with scissors about 3cm above the compost. Pull radishes as soon as they are the size of a 10p piece, before they turn woody and hot. Pick tomatoes when they come away with a gentle twist, and leave the rest on the windowsill if they refuse to ripen on the plant. A pot by the door that feeds you through the summer is one of the quiet pleasures of a British home, and it takes less room than you would think.