Read the wind before you plant anything

Balconies are peculiar growing spaces. They can be sun-traps and heat-sinks in July, yet funnels for every gust that comes down the street. Wind is the real enemy: it strips moisture from compost far faster than sun alone, and it snaps brittle stems at the point where they are least flexible. Before you buy a single pot, spend a fortnight watching your balcony at different times of day.

Ask yourself a few practical questions. Which direction does the prevailing wind come from, and is it channelled between buildings? Does it hit the railings and swirl, or sweep straight across? How many hours of direct sun does the surface get, and does rain ever reach your pots, or does the wall above keep them dry? A corner balcony is usually the worst offender, with two exposed sides and constant turbulence.

Once you know your site, you can work with it. A north-facing, wind-scoured balcony is no place for sun-hungry tender plants, but it will grow excellent salads, herbs and ferns if you choose compost and containers with care.

Choose pots that will not budge

On a windy balcony, weight is your friend. The heavier the container, the less likely it is to rock, tip or shuffle along the tiles in a squall.

• Go bigger than you think. For anything shrubby, start at 40–45cm in diameter. Small pots dry out quickly and topple easily.
• Pick dense materials. Glazed ceramic, cast stone and concrete stay put. Thin plastic is light but needs ballast, and terracotta can crack in a hard frost.
• Choose low, wide shapes over tall, narrow ones. A squat pot with a broad base is far more stable than a tall column that catches the wind like a sail.
• Group your pots together. Massed containers shelter one another, create a damper microclimate and look better too. Put the heaviest at the windward edge.
• Secure window boxes properly. Use brackets fixed into masonry, not resting on the rail, and check your lease or freehold rules before drilling.

Pot feet or risers improve drainage and stop waterlogging, but make sure they do not leave the pot perched and unstable. If you garden on an upper floor, spread weight sensibly and avoid a single enormous planter.

Compost, drainage and watering

Wind and sun together can dry a pot out in a morning. Use a blend of peat-free multipurpose compost and a soil-based mix such as John Innes No 2 or 3. The loam gives weight, holds moisture longer and buffers the roots against fluctuating conditions. Mix in roughly a fifth by volume of horticultural grit for drainage, then top-dress with a 2cm layer of gravel to slow evaporation and stop the surface blowing about.

Water thoroughly rather than little and often — soak until it runs from the drainage holes, ideally in the early morning or evening. In a hot, breezy July you may need to do this twice a day. Self-watering containers with a reservoir are worth the investment on an exposed balcony, but a saucer is not a substitute; it simply keeps the base sodden.

Plants that shrug off a gust

Compact, tough and preferably aromatic or grassy is the rule. Silver and grey foliage often signals wind tolerance, because those leaves are adapted to dry, exposed places.

• Herbs: lavender, rosemary, thyme, sage, oregano and chives all thrive in pots and cope with buffeting.
• Flowers: pelargoniums, osteospermum, verbena, Erigeron karvinskianus, hardy geraniums and dwarf cosmos all flower generously without flopping.
• Grasses and foliage: blue fescue, pheasant grass and sedum give structure and movement without shattering.
• Spring bulbs: dwarf narcissi such as 'Tête-à-Tête' and low tulips flower before the worst of the summer wind.
• Winter interest: skimmia, ivy, heathers, winter pansies and cyclamen keep pots looking alive from November to March.

Avoid tall, top-heavy plants — delphiniums, hollyhocks and full-height sunflowers will be snapped or stripped. Pinch out growing tips in late spring to encourage sturdier, bushier growth, and stake anything borderline with pea sticks or birch twigs pushed in early, before the plant needs them.

Build a simple screen

A screen takes the sting out of the wind rather than blocking it entirely. Solid barriers create fierce turbulence on the leeward side, so aim for something around 40–50% porous.

Wooden trellis fixed to the wall on brackets works well, and gives you something to tie climbers into. A woven willow or hazel hurdle is prettier, and lets just enough air through. Ready-made windbreak netting on a sturdy frame is the budget option. Whatever you choose, fix it into masonry with proper plugs, not into render, and make sure it does not obstruct ventilation, drainage or a fire escape. Screen roughly the lower metre or so where your pots sit — that is where the damage happens.

Plants can screen too. A row of lavender, or a clipped box or privet in a sturdy pot, slows the wind and looks far better than netting.

Looking after it through the year

In early spring, refresh the top 5cm of compost and add a slow-release feed. Wait until the risk of frost has passed — usually late May in most of the UK, later in the north — before planting out tender bedding. Through summer, deadhead regularly and feed weekly with a high-potash tomato feed to keep flowers coming. Come autumn, plant spring bulbs and swap summer bedding for heucheras, cyclamen and pansies.

In winter, cut back watering but never let pots dry out completely. Move them to the most sheltered corner and raise them onto feet so they drain freely. Before a forecast gale, lay tall pots on their sides or bring them inside — it takes five minutes and saves a season's work.