Vertical gardening is growing upwards instead of outwards: training plants up a trellis, a wall, a fence or a tower, so a small garden can grow far more than its ground area suggests. It is the answer to a small patio, a narrow balcony, a shady wall that could be productive, or a garden where the ground is already full. A wall of beans, a trellis of cucumbers, a tower of strawberries or a fence covered in flowers can turn a blank surface into a garden. But vertical gardening has its own problems — weight, watering, wind and light — and a structure that is not built for the weight it will carry is a hazard, not a garden. This guide explains how to grow upwards safely and well.
The idea is simple: many plants naturally want to climb, and many more can be trained to grow up a support. Climbing beans, peas, cucumbers, squash, tomatoes, grapes and roses all grow upwards if you give them something to hold onto. Even plants that do not climb can be grown in wall planters, pockets and towers, stacked one above another. The result is more growing space, better air circulation around the plants, less disease from soil splash, and a harvest at a comfortable height instead of at ground level.
Structures: trellises, walls, towers and frames
The structure is the first decision, and it must be strong enough for the job. A trellis for beans or peas can be light: bamboo canes in a wigwam, a simple frame of battens, or netting stretched between posts. A trellis for a grape vine, a climbing rose or a heavy squash needs to be far stronger: stout posts set in the ground, a frame fixed firmly to a wall, and wire or battens that will not bend under the weight of a mature plant in full leaf and fruit. A wall planter — pockets, troughs or a felt system fixed to a wall — must be fixed to a sound wall with fixings rated for the weight of wet soil and mature plants, because wet soil is heavy, and a planter that falls off a wall is dangerous.
Check the structure before you plant, and check it again as plants grow. A trellis that is fine for young beans can collapse under the weight of a mature crop in wind and rain. Fix trellises to walls with a gap behind them, so air can circulate and the wall can dry, and so you can reach behind to train and tie plants. Do not fix a heavy planter to a fence that is not built to carry it: a fence panel is not a wall. If you are unsure whether a wall or fence can carry the weight, ask someone who knows, and do not guess — a falling planter can injure someone. If you are unsure about fixings or structures in your area, check your local extension service for advice.
Weight and watering: the two problems
Weight is the problem most vertical gardeners underestimate. Wet soil is heavy, a mature plant in full leaf is heavy, and a plant in fruit is heavier still. A wall planter that feels light when you fill it with dry mix can weigh several times more after rain. Build for the wet weight, not the dry weight, use strong fixings, spread the load across several fixings, and do not overload a structure. Check fixings each year, because screws rust, wood rots, and a structure that was safe last year may not be safe this year.
Watering is the other problem. Vertical plantings dry out fast, because they are exposed to sun and wind on all sides, and because water runs down through a tower or wall planter to the bottom, leaving the top dry and the bottom wet. Water slowly and thoroughly, so the mix has time to absorb it, and water the top of a tower first, letting it drain down. A drip irrigation system is almost essential for a large vertical garden: it waters slowly, evenly and reliably, and it saves the daily hand-watering that a wall of pots otherwise needs. The watering calculator gives a starting point for how much water vertical plantings need. Mulch the surface of wall planters and towers to hold moisture, and use a moisture-retentive mix with compost and coir, not a mix that drains too fast. In winter, vertical plantings freeze harder than beds, because they are exposed on all sides, so protect them or move them under cover; our winter frost protection guide covers the winter side.
Light and position
Light is the third problem, and it is easy to get wrong. A north-facing wall gets little direct sun, so it suits shade-tolerant plants such as ferns, hostas and leafy herbs, not tomatoes or beans. A south-facing wall gets the most sun and the most heat, so it suits tender climbers and fruit, but it also dries out fastest and can scorch plants in summer. An east-facing wall gets morning sun and is gentler, while a west-facing wall gets hot afternoon sun. Plants at the bottom of a vertical planting get less light than plants at the top, because the plants above shade them, so put the tallest or most light-hungry plants at the top, or where they will not shade the plants below. The sunlight calculator — listed on the tools hub — helps you work out how much sun a wall or spot gets. Our container gardening guide covers the pot and mix side, because most vertical plantings are, in effect, containers on a wall.
What grows well vertically
Climbing vegetables are the most productive vertical crops: runner beans, French beans, peas, cucumbers, courgettes and squash trained up a trellis, tomatoes tied to a frame, and grapes on a wall. Our growing tomatoes and growing peas guides cover two of the best. Strawberries grow well in towers and wall planters, where the fruit hangs clear of slugs and soil. Herbs such as thyme, oregano, parsley and mint grow well in wall pockets, and they are easy to pick at eye level. Flowers such as sweet peas, morning glory, clematis, jasmine and climbing roses are made for trellises and walls, and they turn a blank fence into a feature. Our growing roses guide covers the climbing side of roses. Leafy salads and herbs do well in a tower, where they can be picked leaf by leaf. Root crops do not suit vertical gardening, for obvious reasons — they need depth, not height.
Training, tying and feeding
Vertical plants need training and tying, or they will grow where they like, not where you want them. Tie stems loosely to the support with soft string or twine, in a figure of eight so the stem is not strangled, and check ties regularly, because a stem grows thicker and a tight tie will cut into it. Train young shoots in the direction you want them to grow, and pinch out the growing tip when the plant reaches the top of its support, so it bushes out instead of growing past the trellis. Prune and thin vertical plants so air can circulate, because still, damp air in a dense vertical planting encourages disease.
Feed vertical plants regularly, because their soil is limited and their food runs out fast. A balanced liquid feed every week or two in the growing season suits most vertical vegetables and flowers, and herbs need less. Our fertilizing vegetables guide covers feeding. Stop feeding in autumn and winter, when plants are not growing. In winter, a vertical structure should be checked, repaired and, if it held tender plants, cleared and stored or protected; our winter garden cleanup guide covers the end-of-season tidy.
Pros and cons of vertical gardening
The advantages are more growing space in a small area, better air circulation and less disease, easier picking at a comfortable height, and a garden that uses walls and fences that would otherwise be bare. The disadvantages are the cost and work of building strong structures, the weight and the risk if a structure fails, the watering — vertical plantings dry out fast and need frequent watering or irrigation — and the light, because plants shade each other. Vertical gardening is not a way to grow more with less work. It is a way to grow more in less ground, with more attention.
Common mistakes
The most common mistake is a structure that is not strong enough for the wet weight of soil and mature plants, which can collapse or fall off a wall. The second is underwatering, because vertical plantings dry out fast and water runs through them. The third is planting light-hungry crops on a shady wall, where they will never thrive. The fourth is planting the tallest plants at the bottom, where they shade everything below. The fifth is tying stems too tightly, so the tie cuts into the stem as it grows. The sixth is forgetting to feed, so plants run out of food mid-season. And the seventh is leaving a vertical planting unprotected in winter, when it freezes harder than a bed. If you are unsure about structures, weight or plants for your wall, check your local extension service for advice.
Frequently asked questions
What can I grow vertically?
Climbing beans, peas, cucumbers, squash, tomatoes, grapes, strawberries in towers, herbs in wall pockets, and climbing flowers such as sweet peas, clematis and roses. Root crops do not suit vertical gardening, because they need depth, not height.
How do I water a vertical garden?
Slowly and thoroughly, so the mix absorbs it, watering the top first and letting it drain down. Vertical plantings dry out fast, so check them daily in summer, mulch the surface, and consider drip irrigation for a large vertical garden.
How strong does a trellis need to be?
Strong enough for the wet weight of soil and mature plants, plus wind. A light trellis suits beans and peas; a grape vine, climbing rose or heavy squash needs stout posts, a firmly fixed frame, and strong wire or battens. Never fix a heavy planter to a fence that is not built to carry it.
Which wall is best for vertical gardening?
A south-facing wall gets the most sun and suits tender climbers and fruit, but dries out fastest. A north-facing wall suits shade-tolerant plants only. East is gentler, west is hot in the afternoon. Match the plant to the wall, not the other way round.
Do vertical gardens need more feeding?
Yes, because the soil in a wall planter or tower is limited and its food runs out fast. Feed vegetables and flowers with a balanced liquid feed every week or two in the growing season, and herbs less often. Stop feeding in autumn and winter.