The Dewybeacon Logo

Start With the Light You Actually Have

Before you buy a single seed packet, spend a day watching your balcony. Most fruiting vegetables — tomatoes, chillies, peppers, courgettes — need six hours of direct sun to crop well. A south-facing balcony will give you that easily, and the wall behind it will hold warmth into the evening, which suits tomatoes and chillies down to the ground.

East-facing spots get strong morning sun, which is excellent for salad leaves and herbs because it dries the foliage early. West-facing balconies are warm but arrive late to the party, so choose quick, forgiving crops. North-facing is the tricky one, but it is not hopeless: rocket, chard, spinach, mint, parsley and land cress will all manage in bright shade, and they will bolt far less quickly than they would in full sun.

Also check the practicalities. Is there a drain you must not block? Will water drip onto the balcony below? A saucer under every pot keeps the peace with neighbours and stops nutrients washing away.

Choose Compact Varieties That Earn Their Space

You cannot grow a cordon tomato that reaches two metres on a balcony, but you do not need to. Breeding has given us dozens of genuinely small, genuinely productive plants.

• Tomatoes: look for bush or tumbling types such as Tumbling Tom, Red Alert or Gardeners Delight grown as a single-stem cordon in a large pot. These stay manageable and crop heavily in a 20–30 litre container.
• Chillies: Apache, Prairie Fire and Cayenne are compact, ornamental and generous. Chillies need a long season, so sow indoors from January to early March.
• Salad leaves: cut-and-come-again mixes, Salad Bowl, Lollo Rossa, rocket and mizuna. Sow a small pinch every two to three weeks from March to August for a continuous supply.
• Herbs: basil, flat-leaf parsley, chives, mint (always in its own pot, or it will take over) and thyme.

Skip anything described as "vigorous" or "spreading". On a balcony, small and repeat-cropping beats big and greedy every time.

Pots, Depth and Compost

Depth matters more than width. Shallow, wide troughs look tidy but dry out in a morning and leave roots nowhere to go.

• Tomatoes and chillies: 30–40cm deep, minimum 10 litres per plant, ideally 20–30. One plant per pot.
• Salad leaves and herbs: 15–20cm deep is plenty; a 30cm trough holds a good row.
• Root crops: carrots and radishes need 25cm of stone-free compost and a deep, narrow container.

Use a peat-free multipurpose compost and mix in roughly a handful of horticultural grit or perlite per pot for drainage. Fill to about 2cm below the rim so you can water properly without it running straight off. Raise pots on feet or bricks so excess water escapes freely — sitting in a puddle is the quickest way to rot roots and tempt slugs. Terracotta is heavy, which helps on a windy balcony, but it dries out faster than plastic, so keep an eye on it.

Make Morning Watering a Habit

Water in the morning, and water properly. Early watering means the plant has moisture to draw on through the heat of the day, the foliage dries off before evening, and you reduce the risk of blight and mildew. Evening watering leaves leaves wet overnight — exactly what fungal disease wants.

Water until it trickles out of the drainage holes, then stop. Little and often creates shallow roots and weak plants. On a hot July day, a tomato in a 25cm pot may need watering twice, so check by pushing a finger two knuckles into the compost; if it is dry at that depth, water. A layer of gravel or compost mulch on the surface slows evaporation considerably.

Feed, Shelter and Pollinate

Compost nutrients run out after about six weeks. Start feeding tomatoes and chillies with a high-potash tomato feed once the first flowers set fruit, following the bottle rate weekly. Salad leaves need almost nothing — a weak liquid feed only if they look pale.

Balconies are windy, and wind damages leaves and topples pots. Choose low-growing varieties, group pots together for mutual shelter, and consider a temporary fleece or bamboo screen in exposed spots. Tying tall plants to a sturdy cane fixed to the wall helps enormously.

Pollination can be patchy on upper floors where bees are scarce. Tap tomato trusses gently at midday, or stroke each flower with a soft brush, and you will set far more fruit.

A Simple First Season

Start modestly: two tomato plants, two chillies, three herb pots and a salad trough. Sow tomatoes and chillies indoors in late February or March, pot them on as they grow, and harden them off gradually before moving them outside after the last frost — late May in the south, early June in the north. Keep an eye out for aphids and whitefly, and deal with them by squashing or a jet of water before they build up.

By August you will be picking warm cherry tomatoes straight from the stem, snipping leaves for a sandwich, and wondering why you waited so long to start.