Balcony plants and window boxes

A window on the wonderful world of gardening

The scale is small but there’s not much you can’t plant in a window box or on a balcony, says Phil McCann

Everyone can grow plants even if they don’t have a traditional garden. Balconies and window boxes can provide perfect growing conditions for a wide range of specimens. And weeding and maintenance doesn’t take a long time.

Before launching into a frenzy of plant-buying it’s best to check that your window box is secure and won’t injure passers-by if it were to fall. Balconies on higher levels may even have weight limits so do check before lugging up tons of compost. Play safe, plant well and create something you can be truly proud of.

Plants in containers on balconies and in window boxes have the same requirements as any other plant. They need a compost to get their roots into and a loam-based recipe, such as a John Innes formulation, is ideal. It provides the necessary nutrients and weight to avoid drying out.


Containers can dry out quickly, especially when exposed to high winds, as can plants growing in window boxes. Take care when watering window boxes and try to avoid showering anyone walking beneath. It is easier to care for plants on balconies and window boxes in colder weather as wrapping them in bubble plastic or hessian is a simple task when plants are outside a patio door or window.

If plants are to survive in cold areas, it is a good tip to line the pots on the inside with black plastic or bubble plastic before planting up. The plastic acts as a layer of insulation in extreme temperatures.


Pick your box: it can be plastic (light), terracotta (natural-looking) or wooden (looks chic). Now the plants. It’s a bold statement, but anything can be grown on a balcony, even trees.

Traditional bedding plants are perfect for window boxes and most containers. Lobelia, both upright and trailing, are readily available and look terrific draped over the surface of pots. Petunias and begonias offer traditional foliage, colours and fragrances. Scented leaf pelargoniums will really impress visitors.

A pinch of annual flower seed sprinkled over the top of the compost in a window box or any container on a balcony will germinate and produce flowers within a couple of months. Wildflowers can be sown the same way.


Herbs are ideal candidates for all containers however small. Parsley, coriander, basil, lavender and thyme are wonderful. Prostrate rosemary will sprawl over pots and nasturtiums, with their hundreds of edible flowers per plant, will add spectacular colour to displays and salads alike.

And vegetables shouldn’t be overlooked. Of course, massive cauliflowers or scale-breaking cabbages may be out of the question but golf ball-sized carrots, beetroot, spring onions and finger-sized parsnips are all happy to grow in small containers and window boxes.

Fruit completes the garden picture on your balcony or in your window box. Strawberries are well-suited to containers and window boxes where slugs don’t get the chance to devour the fruits of your labour. Blueberries are gorgeous plants when in leaf, in flower and in berry. Use a compost formulated for heathers, rhododendrons and camellias, labelled as ericaceous, for best results.