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Why Outdoor Tomatoes Are Worth Another Try

There is something quietly satisfying about a bowl of tomatoes you have grown yourself, still warm from the greenhouse or the sunniest corner of the patio. Many UK gardeners assume that tomatoes belong under glass, and it is true that a polytunnel or greenhouse gives you a longer season and a bigger crop. But with the right varieties, a little forward planning, and a sheltered spot that catches the sun, outdoor tomatoes are perfectly achievable in most of Britain. The trick is not to fight the climate but to work with it, choosing plants that ripen quickly and giving them as much warmth and protection as your plot can offer.

Start With Compact Bush Varieties

The single biggest mistake made by gardeners new to outdoor tomatoes is picking a tall, cordon variety bred for greenhouse conditions. Those plants want a long, warm season and will sulk in a cool, damp August. Bush, or determinate, varieties are far better suited to life outside. They grow to a manageable size, stop on their own, and tend to crop over a shorter, more concentrated period, which means you get a decent harvest before the weather turns.

Look for varieties described as early or suitable for cooler conditions. Good choices include:

• Gardeners' Delight — a reliable cherry type with excellent flavour and good tolerance of cooler nights.
• Red Alert — very early, compact, and happy in a large pot on a sunny patio.
• Tumbler — a trailing bush that performs beautifully in hanging baskets, well out of the way of slugs.
• Sub Arctic Plenty — bred for short seasons and surprisingly productive in the north.
• Mountain Magic — a blight-resistant type that earns its place in wetter western gardens.

Blight is the great enemy of outdoor tomatoes, so if you garden in the damp west or in a year with a soggy July, resistant varieties are worth their weight in gold. Grow two or three different types and you spread your risk.

Sowing, Potting On, and Hardening Off Slowly

Sow indoors in late February or early March if you have a warm windowsill, or in a heated propagator for the quickest start. Prick the seedlings out into individual pots as soon as the first true leaves appear, and keep them somewhere bright but not scorching, or they will grow leggy and thin.

The move outdoors is where many crops are lost. Hardening off is not a single afternoon on the patio; it is a gradual process over a week to ten days. On the first day, put your plants outside for just an hour or two in a sheltered, shaded spot. Increase the time each day, gradually exposing them to more sun and cooler air, and bring them in at night. By the end of the process they should be spending the night outside, provided the forecast is kind.

Do not plant out until the risk of frost has passed. In most of southern England that means late May; further north, early June. Cold soil stalls growth far more than cool air, so wait until the ground has genuinely warmed.

Choosing and Preparing the Right Spot

Tomatoes want sun, shelter, and free-draining soil. A south or south-west facing wall is ideal, and the retained warmth from brickwork will nudge your plants along. Failing that, a fence, a hedge, or a line of tall plants on the windward side will all help.

If your soil is heavy clay, dig in plenty of well-rotted compost the previous autumn. Alternatively, grow in large pots or grow-bags against a warm wall, which gives you far more control over moisture and lets you move plants under cover if the weather turns. A pot of at least 10 litres is sensible for a bush variety. Add a handful of slow-release fertiliser at planting time, and water the hole before you settle the plant in so the roots go down into moisture. Plant slightly deeper than the plant was in its pot; tomatoes will root along the buried stem.

Watering and Feeding for Steady Growth

Inconsistent watering is the main cause of split fruit. When the soil dries out and then you flood it, the fruit takes up water faster than the skin can stretch, and it cracks. The answer is boring but effective: water little and often, aiming for soil that is consistently moist rather than alternately dust and swamp.

• Water in the morning where possible, directing it at the soil rather than the leaves.
• In a wet summer, ease off — overwatering is just as damaging as drought.
• Once the first truss has set, begin a high-potash liquid feed every ten to fourteen days.
• Mulch with compost or grass clippings to even out moisture swings.
• Remove side shoots on any cordon types, but leave bush varieties to get on with it.

If a spell of heavy rain is forecast just as your fruit is ripening, consider rigging a simple clear plastic canopy above the plants. It keeps the worst of the wet off and does wonders against blight.

Harvest, Ripening, and Late-Season Tricks

Pick tomatoes when they are fully coloured and slightly soft to the touch; flavour develops on the plant. If the season runs short and you are left with a truss of green fruit in September, lift the whole plant and hang it upside down in a cool, dark shed. The tomatoes will ripen slowly over several weeks. Alternatively, lay green fruit on a tray with a ripe banana and let the ethylene do its work.

Outdoor tomatoes demand a bit more patience than greenhouse ones, but they reward that patience handsomely. Choose compact, early varieties, harden them off properly, keep the water steady, and give them the warmest sheltered corner you have. Come August, you will be glad you did.