Why a Sunny Patio Is Perfect for Tomatoes

Tomatoes are sun worshippers, and a south or south-west facing patio is one of the warmest, brightest spots in any UK garden. Walls and fences radiate heat back onto your plants long after the sun has dipped, which is exactly the microclimate that ripening tomatoes crave. If you have a corner that basks in six or more hours of direct sunshine a day, you already have the foundations of a reliable harvest. The trick is choosing the right varieties and keeping on top of watering and feeding, because a plant growing in a pot has no subsoil to fall back on. Get those basics right and a modest collection of containers can easily outperform a tired old greenhouse bed.

Pick Compact Varieties for Pots

Not every tomato suits container life. Tall indeterminate cordon varieties will sprawl and sulk if they are not pinched and staked properly. For patio growing, look for bush types, dwarf cordons and anything described as suitable for hanging baskets or grow bags. These stay manageable, fruit earlier and forgive the occasional missed watering far better than a greedy beefsteak.

• Tumbling Tom – a classic trailing bush for baskets and tall pots, with sweet cherry-sized fruit.
• Gardeners' Delight – a reliable cordon producing heavy crops of small, flavourful cherries if you pinch out side shoots.
• Maskotka – a compact bush that fruits well outdoors in a poor summer.
• Red Alert – short, early and generous, ideal for a first-time patio grower.
• Mountain Magic – a blight-resistant type that earns its keep in damp western counties.

Buy young plants in late spring or raise your own from seed on a bright windowsill from late February. Whatever you choose, stick to one or two varieties until you know how your patio behaves.

Choose the Right Container and Compost

Size really does matter. A tomato plant in a tiny pot will dry out, run short of nutrients and produce a scattering of sad fruit. Aim for a container of at least 30cm (12 inches) across and 30cm deep per plant – a standard 10-litre pot is the sensible minimum, with 15 litres better still. Terracotta and dark plastic look smart, but they warm up quickly and lose moisture, so glazed or light-coloured pots often perform better. Whatever you use, check the drainage holes and lift containers onto pot feet or bricks so water can escape freely.

Fill with a good-quality peat-free multipurpose compost, or a dedicated tomato compost if you prefer. Don't be tempted to reuse last year's compost from a tomato pot; it will be exhausted and may harbour disease. Mix in a slow-release fertiliser at planting time and firm the compost gently around the roots, leaving the stem buried a little deeper than it was in its original pot to encourage new roots.

Support, Pinch and Water Wisely

Bush varieties need nothing more than a short cane to stop them collapsing under their own fruit. Cordons, however, climb and need a tall bamboo cane or a spiral support pushed firmly into the pot at planting time. Tie the stem in loosely with soft twine every 20cm or so as it grows, and pinch out the side shoots that appear in the leaf joints to keep the plant focused on fruiting rather than foliage. Once four or five trusses have set, nip out the growing tip to encourage the remaining fruit to ripen.

Watering is where most patio growers trip up. Little and often beats the occasional flood, because erratic moisture causes split skins and blossom end rot. Aim to keep the compost evenly moist, never soggy and never bone dry. In high summer, a plant in a 10-litre pot may need watering twice a day. A simple drip or capillary watering system takes the worry out of holidays, and a layer of gravel or compost mulch over the surface slows evaporation. Always water the compost, not the leaves, and do it in the morning where you can.

Feeding for a Long, Generous Crop

Once the first tiny fruits appear, start feeding weekly with a high-potassium tomato fertiliser – the sort that encourages flowers and fruit rather than leafy growth. Follow the dilution instructions on the bottle rather than guessing, and never feed a dry plant; water first, then feed, or you risk scorching the roots. If you spot yellowing lower leaves and weak growth, a nitrogen-rich feed will help early on, but switch to tomato feed as soon as flowering begins. A fortnightly seaweed tonic as a foliar spray can lift plants that look tired after a cold, grey spell.

Keep Pests and Weather in Check

UK patios come with their own challenges. Blossom end rot, that dark sunken patch on the base of the fruit, is a calcium uptake problem caused by uneven watering rather than a shortage in the compost – steady moisture is the cure. Blight arrives with warm, humid spells and can wipe out outdoor tomatoes overnight, so remove affected leaves promptly and choose resistant varieties if you garden in the damp west. Watch for whitefly under the leaves and greenfly on soft tips; a firm spray with water dislodges most of them.

• Ventilate a sheltered corner on still, muggy days to reduce fungal problems.
• Remove the lower leaves once the first trusses set, to improve airflow.
• Pick fruit as it ripens to keep the plant producing, and ripen late green tomatoes indoors on a sunny windowsill.

With a warm wall behind them, a generous pot beneath them and a little regular attention, container tomatoes will reward you right through to the first frosts. There is nothing quite like eating a sun-warmed tomato on the very patio where it grew.