RHS Growing Guides
How to grow tomatoes
Our detailed growing guide will help you with each step in successfully growing Tomatoes.
Getting Started
Cherry tomatoes are sweet and delicious, especially when harvested from your own plants
Tomatoes do need some attention to grow well, including protection from frost, and regular watering and feeding. But they’re well worth the effort when you can eat your own home-grown tomatoes all summer long, freshly picked, warmed by the sun, and at their sweetest, juiciest best.
There’s an enormous range of varieties to choose from, which is another great benefit of growing your own. There are fruits of different sizes, colours, textures and flavours, to suit all tastes – far more choice than you get in the supermarket. There are plants of various sizes too, for different growing locations and amounts of space, from tall and vigorous
Month by Month
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Choosing
There’s a huge array of tomato varieties available to grow from seed
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Cordon (or indeterminate) tomatoes are vigorous, fast-growing plants that get very tall and need suitably tall supports, both in a greenhouse and outdoors. As they grow vertically, they take up very little ground space. But they need regular maintenance – watering, feeding, tying to supports and removing side-shoots
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Bush (or determinate) tomatoes are naturally more compact plants, great for smaller spaces. Trailing types can also be grown in windowboxes and hanging baskets, with the stems cascading over the sides. These are the easiest type to grow and need little maintenance apart from watering and feeding. The stems may need support when heavily laden with fruit
Check seed packets or plant labels before buying, to ensure you get the type to suit your growing space.
There are also lots of tomato varieties to choose from, offering fruits of various sizes, shapes, flavours and levels of sweetness. Fruit colours range from traditional red to dark purple, pink, orange, yellow or green, and even striped. There are heirloom varieties, grown for many generations, as well as modern, disease-resistant choices. There are small round cherry fruits, elongated plum varieties, uniform, medium-sized salad tomatoes and huge, wrinkled, mis-shapen beefsteaks, all full of flavour and with their own individual characters. For varieties that will reliably produce good crops, look for those with an RHS Award of Garden Merit (AGM) – see our list of AGM fruit and veg and our Recommended Varieties below. You’ll also find tomatoes growing in the veg gardens and greenhouses in all the RHS gardens over the summer months, so do visit to compare varieties and pick up growing tips.
What and where to buy
Tomato seeds are widely available from garden centres and other seed stockists. Many also sell young plants in spring and early summer. These are ideal if you don’t have the time or space to grow from seed, but the choice of varieties is limited. Grafted plants are a recent introduction – these are generally more vigorous than seed-grown plants, providing earlier and larger crops, and greater resistance to disease. However, they are more expensive and the choice of varieties is currently fairly small. Grafted plants are mainly available from online suppliers.
Recommended Varieties
Beefsteak – the large fruits are pink and thin skinned with a rich flavour. Cordon type.
Beefsteak – deep-red, ribbed, early maturing fruit, valued by chefs. For greenhouse. Cordon type.
Salad – early, reliable crops of tasty fruits. Disease resistant. Cordon type.
Sowing
Sow tomato seeds in warm conditions, into modules, small pots or seed trays
For full sowing instructions, see our guides below.
Pricking out and potting on
After a couple of weeks, once the seedlings have a couple of true leaves, move them into individual pots or modules of peat-free multi-purpose compost. Lift each seedling individually, using the dibber to support its rootball, and hold it by a leaf rather than the delicate stem. If the seedling is leggy, replant it more deeply, so the first pair of leaves is just above the compost surface. Keep in a bright location, with a temperature of at least 16°C (60°F), and water regularly. After about a month, they should be ready to plant in their final position.
Planting
Young, well-rooted tomato plants, either grown from seed or recently bought, can be planted into their final position in early summer, once temperatures are reliably above 16°C (60°F). You can plant them in large containers or growing bags in a greenhouse or outdoors, or plant them in the ground. To grow outdoors, choose a really warm, sunny, sheltered location.
Plant tomatoes deeply, so the first set of leaves is just above the soil surface – the buried section of stem will then produce additional roots. Tomatoes are tender, so before planting out, acclimatise them to garden conditions by hardening off.
Planting in containers
Pots or growing bags are ideal for tomatoes, whether in a greenhouse or outdoors
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Bush types are compact and ideal for large patio containers, troughs, windowboxes and even hanging baskets
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Cordon types grow well in large containers, with a tall cane for support. This can make the pots top-heavy, so position in a sheltered site, ideally against a sunny wall. In a greenhouse, you can use canes or vertical strings for support – tie the stings to the roof, so they hang down vertically, and bury the other end under the rootball when you plant. The string should be quite slack, so it can be wound round the top of the main stem as the plant grows. See Pruning and Training, below
Planting in the ground
Tomatoes thrive in rich, free-draining but moisture-retentive soil, so add plenty of garden compost before planting. Choose your warmest, sunniest spot, sheltered from wind. Space plants 45–60cm (18–24in) apart, depending on their eventual size – check seed packets for exact spacings. With cordon tomatoes, insert a sturdy cane next to the plant and tie in the main stem loosely.
Avoid growing tomatoes in the same bed in consecutive years, to prevent the build-up of diseases in the soil. Alternatively, you can use a growing method called ring culture in a greenhouse border.
Plant Care
Watering
Water tomato plants regularly to keep the soil or compost evenly moist. Fluctuating moisture levels can cause problems with the fruit, such as splitting or blossom end rot (see Problems, below). Plants in containers dry out quickly, so they may need watering daily in hot weather. Curling leaves can be a sign that a tomato plant is short of water.
Feeding
To boost fruiting, especially with plants in containers, feed every 10–14 days with a high potassium liquid fertiliser once the first fruits start to swell.
Mulching
Lay a thick layer of mulch over the soil around tomato plants to help hold in moisture and deter weeds. Use garden compost or well-rotted manure, but leave a gap around the base of the stem, to prevent rotting.
Improving pollination
When growing tomatoes in a greenhouse, open the vents regularly to give pollinating insects access to the flowers. You can also lightly tap or shake the flowers when fully open to aid pollen transfer within the flower. Misting flowers with water may also help.
Pruning and Training
With cordon tomatoes, remove the side-shoots sprouting from above each leaf
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Cordon tomatoes are grown as tall, single-stemmed plants – they need tall supports and the side-shoots should be removed regularly. This keeps these vigorous plants in check and ensures they put their energy into fruit production – see details below
- Bush tomatoes are more compact and their side-shoots should be left to grow. Plants may need support if they grow quite large. Also, if they carry a heavy crop of tomatoes, the side-shoots may start to droop or be at risk of snapping. If so, simply add short vertical canes when and where required, tying in the shoots loosely
Also see our video guides below for our expert tips on cordon training and removing side-shoots.
Cordons: training up supports
Cordon tomatoes need support, usually either a tall sturdy cane or a vertical string coming down from an overhead horizontal support, such as a greenhouse roof, and anchored under the plant’s rootball at planting time. However, tomatoes don’t cling to supports or twine round them naturally, so must be attached by hand as they grow. If using a cane support, simply tie the main stem to it at regular intervals as it grows. If using a vertical string, gently wind the string around the top of the main stem once or twice a week as it grows.
When plants reach the top of their support or have set seven fruit trusses indoors or four trusses outdoors, remove the growing point of the main stem at two leaves above the top truss.
Cordons: removing side-shoots
Cordon tomatoes are best grown as single-stemmed plants. However, these vigorous plants naturally produce side-shoots from the joints where leaves sprout from the main stem. These side-shoots should be removed to keep plants growing vertically on just one stem. If they’re not removed, the side-shoots grow rapidly, forming a mass of long, scrambling, leafy stems that are difficult to support, produce few fruits and take up a lot of space.
Removing the side-shoots is simple – every time you water, check the plant for any shoots sprouting just above each leaf, from the joint between the leaf and the stem. Pinch these out or snap them off. See how to identify and remove side-shoots in our video guide.
Harvesting
You can’t beat the flavour and scent of freshly harvested tomatoes
At the end of the growing season, lift outdoor plants with unripe fruit and either lay them on straw under cloches to ripen or pick the fruits and place somewhere warm and dark to ripen. Alternatively, put unripe tomatoes in a drawer with a banana, to aid ripening.
Problems
In a warm summer, tomatoes are easy to grow and will fruit readily if watered on a regular basis. However, problems can occur when growing conditions aren’t ideal, and plants can also be affected by several diseases and sap-sucking insects – see Common problems below for more details.
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