Why a Wall Is the Most Underused Growing Space You Own

Most UK gardens and courtyards have two kinds of space: the floor, which is crowded with bins, bikes and a barbecue, and the walls, which are usually bare. A wall is a vertical allotment. It gets light, it sheds rain, and it is protected from slugs and from the worst of the frost that settles at ground level. Fix a planter to it and you can grow a serious amount of greenery in an area roughly the size of a tea towel.

Courtyard gardens, narrow side returns and balconies are particularly well suited to this approach. A typical Victorian terrace courtyard might be four metres by five, with two walls facing south or west and a fence on the shaded side. That is perhaps twenty square metres of growing surface, which is more than most people have in a border. The trick is to choose planters that will genuinely carry the weight, and to plant them with things that actually enjoy the conditions.

Before you drill a single hole, walk the wall and note how the light moves. A south-facing brick wall can hit 40°C on a July afternoon and will scorch anything tender; an east-facing fence is gentler but dries out slowly and can stay damp through winter. North walls suit ferns, ivy-leaved cyclamen and wood anemone perfectly.

Choosing Planters That Will Still Be There in Five Years

Flimsy plastic troughs are cheap and cheerful, but they fade, crack and warp within two or three seasons, and a cracked trough full of wet compost is a genuine safety concern above head height. Spend a little more and buy once.

• Powder-coated steel or aluminium: light, rust-resistant and available in long, slim troughs that suit a fence line. Look for a depth of at least 20cm.
• Glazed stoneware or frost-proof terracotta: heavy, but stable and beautiful. Ideal at chest height where you can see the finish. Check drainage holes are generous.
• Timber troughs lined with butyl: warm-looking and good on a shed or garage wall. Untreated timber will rot in two winters; use a rot-resistant liner or a plastic insert.
• Wool or felt pocket planters: excellent for lettuce, strawberries and trailing herbs on a sheltered wall, but they dry out fast and rarely last beyond three summers.

Whatever you choose, match the planter width to the wall. A trough that is 15cm deep front to back holds very little compost and will need watering twice a day in summer. Aim for 25–30cm if you have the space, particularly for ferns and anything with a decent root run.

Fixing Them Safely to Brick, Render and Fence

This is the part people rush, and it is the part that matters. A fully planted metre-long trough can easily weigh 25–30kg when soaked, and wind loading on a wall increases that dramatically.

• Into brick or block: use a 6mm masonry bit on hammer mode, drill 50mm deep, blow the dust out, then insert a decent nylon wall plug and a 60–70mm screw. Avoid mortar joints where possible.
• Into render or pebbledash: drill through to the substrate behind. Fixings that only grip the render will pull out.
• Into timber fencing: screw into the rails, not the feather-edge boards. If the planter is heavy, run a horizontal batten across three posts and hang the trough from that.
• Into cavity walls: use a proper cavity fixing rather than a standard plug, or bolt through to a batten on the inside of an outbuilding where you can.

Always drill slightly downwards at a shallow angle so water cannot track into the wall, and seal the hole with a dab of clear silicone. Never hang a planter directly above a doorway, a path or a seating area unless you are confident in the fixing. Check fixings each spring — frost and wind work screws loose over time.

What to Plant for Colour, Scent and Cover

Wall planters dry out faster than border soil because they are exposed to wind and reflected heat from the wall itself. Choose plants that tolerate sharp drainage and a bit of neglect.

• Herbs: thyme, oregano, winter savory, rosemary and sage all thrive in a sunny wall. Mint and chives prefer a shadier, moister spot.
• Ferns: hart's tongue, maidenhair spleenwort and soft shield fern look superb on a north or east wall, particularly with a dark planter behind them.
• Trailing flowers: trailing lobelia, bacopa, calibrachoa, ivy-leaved pelargoniums and the delicate Convolvulus cneorum will spill over the front edge and soften the hard line of the wall.
• Evergreen structure: a small clipped box, euonymus or hebe gives the display bones through winter when everything else has gone over.
• Edible extras: alpine strawberries, wild rocket and chard work well in a west-facing trough and crop for months.

Group plants by water need. Thyme and rosemary want gritty, free-draining compost; ferns and mint want something richer that holds moisture. Trying to please both in one trough usually ends with the rosemary rotting in a wet February.

Keeping Wall Planters Alive Through a British Year

Watering is the main job from May to September. A wall planter in full sun may need a soak every morning, and a drip irrigation kit on a timer will save you a summer of guilt. Add water-retaining granules to the compost and top-dress with a gravel mulch to slow evaporation.

Feed fortnightly with a general liquid fertiliser from March to August, switching to a high-potash tomato feed once flowers appear. Come October, empty and store ceramic and timber planters that might crack, and swap summer bedding for winter pansies, cyclamen or ivy. Raise pots slightly off the bracket in winter so they cannot sit in standing water.

Finally, replace a third of the compost each spring. Wall planters are a small, closed system and nutrients vanish fast. Refresh the top layer, trim back anything leggy, and check your fixings while the planter is empty. Done properly, a wall of planters will reward you for years, turning a blank brick face into the best-value growing space in the garden.