Eleanor Hartley
Start with an honest look at your balcony
Before you buy a single pot, spend ten minutes reading your space. Which way does it face, and how many hours of direct sun does it actually get in midsummer? A south or west-facing balcony with six hours or more of sun will happily ripen tomatoes, peppers and chillies. An east-facing one is ideal for salad leaves, herbs and strawberries, which prefer a gentler start to the day. A north-facing balcony is not a write-off, but concentrate on leafy crops and shade-tolerant herbs such as mint, parsley and chives rather than anything that needs to flower and fruit.
Next, think about wind and weight. Balconies are wind tunnels, and a gust can snap a tall tomato stem or send a lightweight pot skittering across the tiles. Then consider the structure itself. Most modern domestic balconies are designed for far less load than a garden border, so keep heavy pots close to the wall rather than lined up along the outer railing, and spread the weight rather than clustering it. If you have any doubt about what your balcony can safely carry, or you rent and are unsure about drilling, ask before you hang anything.
Choose containers that are light but generous
The container is where most balconies go wrong. Terracotta looks lovely but is heavy and dries out fast. Glazed ceramic is heavier still. For a balcony, plastic, resin or fabric grow bags give you far more root space for the same weight, and they hold moisture better than unglazed clay.
Size matters more than you might expect. A plant in a pot that is too small will dry out twice a day in July and never reach its potential.
- Herbs: 2–3 litres per plant is plenty for basil, thyme or chives.
- Chillies and peppers: 5–7 litres per plant, and a stake for support.
- Dwarf beans: 3–5 litres per plant, or three plants in a 15-litre trough.
- Bush tomatoes: 10–15 litres per plant minimum.
- Salad leaves and radishes: a 30cm-deep trough will do nicely.
Whatever you choose, make sure every pot has drainage holes and stands on a saucer or tray. Water running off a balcony and onto a neighbour's washing is a quick way to lose friends.
The crops that genuinely earn their space
Balcony growing rewards generosity of flavour over volume. You will not feed a family from six pots, but you can absolutely keep yourself in fresh herbs, salads and a steady trickle of chillies from late July onwards.
- Cut-and-come-again salad: sow little and often, every three weeks, in a shallow trough. Rocket, mizuna and loose-leaf lettuce are all happy.
- Herbs: basil, mint (keep it in its own pot, it spreads), rosemary, thyme, oregano and flat-leaf parsley. Buy small plants rather than seed for the woody ones.
- Chillies and sweet peppers: compact varieties do best in containers. Pinch out the growing tip when plants are about 20cm tall to encourage bushing.
- Dwarf French beans: bush types need no climbing frame and crop heavily in a trough. Sow in late May once nights are warm.
- Tumbling tomatoes: trailing cherry types spill over the edge of a pot and need no staking. Feed them well and remove side shoots on cordon types.
- Strawberries: three or four plants in a 10-litre pot will give you a small but genuinely delicious harvest in June.
Anchor everything and tame the wind
Wind does more damage than cold on most balconies. A windbreak of netting, willow screening or horticultural fleece fixed at about waist height will take the sting out of gusts, but avoid solid boards or sheeting: they simply push the wind over the top and create damaging turbulence behind.
Weight your pots down, especially tall ones. A brick or two in the base of a large container before you add compost lowers the centre of gravity without costing much root space. For railing-mounted planters, use proper brackets rated for the load and check them after every storm. Never hang a heavy, waterlogged pot over a walkway below, and avoid trailing anything over the edge of a busy pavement.
Watering and feeding on a balcony
Balcony pots dry out faster than border soil, because they are exposed on all sides and often catch reflected heat from walls and glass. In high summer, expect to water daily, and twice a day during a heatwave. Water in the early morning or evening, and water until it runs out of the drainage holes rather than giving a token splash.
A few practical measures make a real difference: mix water-retaining granules into the compost, mulch the surface with gravel or cocoa shell, and group pots together so they shade one another. Self-watering containers are worth the investment if you work long days. Start feeding once plants begin to flower, using a high-potash liquid tomato feed weekly. Herbs and salad leaves need far less, as too much nitrogen gives you floppy, flavourless foliage.
A simple plan for the year ahead
Sow salad and hardy herbs from March onwards under cover, and harden them off before they go outside. Plant up chillies and tomatoes in late May, once the risk of cold nights has passed. Through June and July, keep picking, keep watering and keep an eye out for greenfly, which love sheltered balconies and can be blasted off with a firm jet of water. By August you will be harvesting beans and ripening peppers, and in September you can sow winter salad and parsley for a final crop before the light drops away.
Start small, learn what your particular balcony does with sun and wind, and add a pot or two each season. A productive outdoor space does not need a garden at all.
