How to grow tomatoes and the best varieties

Tomatoes are easy to grow, both in the greenhouse and in the garden. They do well in pots and growing bags so are perfect for patios and balconies too. 

The Which? Gardening experts have trialled and tasted tomatoes to recommend the best varieties for you to grow. Follow advice for how to grow a great harvest.

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How to grow tomatoes: month by month

How to grow tomatoes from seeds

Greenhouse tomatoes

If you sow tomatoes too early the natural light levels will be too low and you'll get tall, leggy plants that won't grow well. Sow tomatoes that will be grown indoors in a greenhouse or polytunnel in mid-March.

Sow the seeds in a pot or small tray of a Best Buy compost for sowing seeds. They need a temperature of 15-20C to germinate so put them on a warm windowsill indoors or in a heated propagator. 

When the seedlings have emerged, they can be moved into individual 7cm pots of a Best Buy compost for raising young plants. Gently hold the leaf - never the delicate stem - and loosen then from the compost by lifting underneath them with a pencil. Then make a hole in the new pot of compost and put the seedling in so that the leaves are just above the the surface of the compost. 

Keep them in a light place - either on a heating mat in the greenhouse or under grow lights in the house. Two weeks after moving them into their own pots, move them into a slightly bigger pot as they'll be growing quickly. Don't feed your plants at this stage.

Discover the best heated propagators

Outdoor tomatoes

Tomatoes are killed by the frost so you don't want them to be ready to plant before the danger of frost has passed in mid to late May. Wait until early April before you sow plants for outdoors. Do it in the same way as for plants for indoors (above).

Try our best frost protective covers

Best tomato varieties

Full testing results for tomatoes

Which? members can log in now to see the full results and which are our Best Buy varieties. If you’re not a member, join Which? to get instant access.

Cherry tomatoes

Salad tomatoes

Beefsteak tomatoes

Plum tomatoes

Hanging basket tomatoes

Outdoor tomatoes

How we test tomatoes 

We grow lots of varieties alongside each other then harvest the tomatoes regularly, and count and weigh the fruit from each variety. We also taste the tomatoes, rating them for taste and texture.

Planting tomatoes

You can either plant in the ground or in large pots or growing bags. If you're using pots, fill them with a mixture of a Best Buy compost for containers and a Best Buy controlled-release fertiliser. There should be 50cm between plants in the ground. Don't plant outdoors until the danger of frost has passed in mid to late May.

To support your plants as they grow, either tie a piece of string to the greenhouse roof and put the end under the tomato plant, or insert a bamboo cane next to the plant. Put the plants in so that the soil or compost comes just below the first pair of leaves. This will encourage the plant to make extra roots so it's more sturdy.

Growing tomatoes in a grow bag

In grow bags, start by preparing the bag. Roll it to fluff up the compost inside, then carefully make slits on the underside for drainage. Work out how many plants to include in each bag by checking the volume of compost in the growing bag. Tomatoes need at least 10L of compost per plant.

Growing tomatoes in pot and hanging baskets

Varieties have been bred to be compact and bushy, perfect for growing in a hanging basket or patio pot. Put one plant in a 40cm-diameter basket or pot and put it outdoors once the danger of frost has past in mid- to late May. Use a Best Buy compost for containers and mix in a Best Buy controlled-release feed.

Training tomatoes

Most varieties should be grown as cordons ie only on one stem. Bush varieties can be left to their own devices, with a few short canes to stop them falling over.

Cordon plants need to be tied to their support regularly and the sideshoots that grow between the main stem and the leaf need to be removed as they appear. This will channel the plant's energy into making flowers and fruit rather than extra leafy growth.

Watering

Tomatoes are thirsty plants so you need to water them regularly - twice a day for plants in containers during hot weather. Try not to get water on the leaves or it can cause disease problems.

Make things easier with our best garden irrigation systems

Feeding tomatoes

Feeding is important to produce the sweetest tomatoes. The easiest way to feed is to add controlled-release feed to the compost when planting in pots. Feed plants growing in the ground or in growing bags by adding a liquid tomato feed to the water after the first flowers appear. 

Plants grown in pots also benefit from doing this in late summer when the controlled-release feed begins to run out.

Discover our best tomato feed.

Ripening fruits

To encourage all the fruits to ripen, pinch out the main growing tip of the plant in early to mid-August and remove any new leaves or flowers that appear. This is to channel the plant's energy to ripening the fruit before the colder weather returns in autumn.

How to ripen green tomatoes

At the end of the season, you're sometimes left with green tomatoes that haven't ripened before the cold weather starts. Remove them from the plants before you pull them up and bring them indoors. 

You may have heard different techniques recommended for ripening green tomatoes, including putting them with a banana, but when Which? Gardening magazine tested different methods we found that putting them in a dark place indoors, such as a drawer, works best. Tomatoes left with bananas were one of the worst methods for causing the tomatoes to rot.

How and when to harvest tomatoes

Harvest from: August to October

You can choose how ripe you you like your tomatoes: half-coloured for tart, firm fruit or full-coloured for sweeter and softer fruits. 

Gently lift the fruit upwards with your thumb on the calyx (the star-shaped green bits at the top of the fruit), to keep it on the fruit after it's picked. This will help the fruit keep for longer.

Each time you pick all the fruits on a truss (group of fruits), remove the leaves below to improve air flow around the plant and make it easier to avoid wetting the foliage when watering.

Storing your harvest

You can freeze whole tomatoes, but it may be easier to make them into dishes, such as tomato sauce or soup, first. You can also slice 6mm strips and put them in a dehydrator machine - these cost about £50.

Common tomato problems

Leaf curl

The upper leaves on the plant may show extensive curling, sometimes being so tightly curled that they are reduced to foliage balls. The leaves function normally so cropping is not affected.

Leaf curling seems to occur when growth is particularly fast. It sometimes happens when the plants have been exposed to low temperatures, so be sure to protect them with fleece on cold nights.

These symptoms seem to be of absolutely no consequence whatsoever and the plants develop and fruit well.

Tomato blight

Late blight (Phytophthora infestans) is similar to potato blight. So keep tomatoes well away from potato crops.

It spreads by air-borne spores, so even if you don’t get it one year, it can blow in the next. Following recent research by the James Hutton Institute, blight alerts for potato and tomato growers are now being issued under the Hutton Criteria, which has replaced the Smith Period.

The minimum temperature needed by the disease, 10°C over two consecutive days, is unchanged, but it's now known that relative humidity only needs to be above 90% for six hours on both consecutive days for the disease to spread, rather than 11 hours, as previously thought.

On the stems, the first signs are large, dark-brown spots, which can spread and kill the plant. Similar spots form on the leaves, although they may be lighter or grey in colour. The leaves are quickly covered, after which they wither and die. The fruits turn a red/brown marbled colour.

The fruit is not poisonous but blight causes it to be inedible as it doesn't ripen and rots quickly.

Blighted plants can be composted provided the temperature in the compost is high enough, such as in a Hotbin. If you're using an open compost bin it's unlikely to get hot enough to destroy the blight spores, so it's best to burn affected plants or put them in the council green-waste bin as their composting facilities run at higher temperatures. There is a possibility that blight spores could overwinter on other plant material but this hasn't been tested scientifically yet. 

You can help prevent blight by choosing outdoor sites that are sheltered from winds. But avoid areas that are so sheltered that air flow is inhibited, leading to damp, still conditions which promote fungus diseases. Avoid growing where potatoes were raised last year; there is a risk that volunteer potatoes can harbour spores and reinfect plants the following year.

Keep the air in greenhouses as dry as you can in humid weather, by ventilating well and avoiding wetting path and foliage when you water. Opening the door and windows in the morning, when outdoor air is cool and dry, is especially helpful, as long as you don’t suddenly chill the plants.

If you don’t have a greenhouse, try erecting a cover to try to keep the foliage dry at all times. Prevent overheating through adequate ventilation and shading.

Watering the soil without wetting the leaves also helps.

Split tomato fruits

Sometimes tomato fruits develop normally, but as they ripen the skins split suddenly, often around the stalk end.

The split fruits can be eaten – you just need to be quick about it. They soon become unappetising as grey mould (botrytis) enters the damaged areas.

Excessively hot or somewhat dry growing conditions cause a reduction in the swelling rate of the fruit and a thickening of the skin. When conditions improve (usually after watering), the fruit puts on a growth spurt and the skin splits. Regular watering and the provision of some shading during very hot, bright periods should reduce the problem.

Make things easier with a best watering can

Greenback

As greenhouse tomatoes ripen, a ring of unripened greenish flesh appears around the stalk end of the fruit. The rest of the fruit ripens as usual and the plant itself looks normal. 

Greenback is a genetically controlled problem that tends to be more common when conditions are very hot and bright in the greenhouse. Low levels of potassium and phosphorous may also exacerbate the symptoms. The ripe part of affected fruits can still be eaten.

Add shading and avoid removing too many of the leaves, as these also provide vital shade. Ensure good ventilation and keep roof vents open to reduce the risk of damaging high temperatures. Most modern F1 hybrids are less prone to greenback, but 'Cristal' and 'Cossack' are particularly resistant.

Blossom end rot

This produces brown, leathery patches at the bottom of the fruit. 

It's caused by a shortage of calcium in the developing fruit, which is as a result of erratic and/or inadequate watering, plus high temperatures. It's most common with tomatoes grown in growing bags, as it is difficult to keep these well watered.

You can still eat the unaffected parts. Cut out the dark patch and eat the rest. If it's not ripe, the damage is likely to prevent further development, and affected fruit are best removed.

Water your plants regularly and help to reduce temperatures by opening the greenhouse doors and any vents and windows.

Tomato moth

Tomato foliage and fruits may be attacked. Initially the small, young caterpillars of tomato moth tend to graze on the surface of new foliage close to the greenhouse glass. 

They increase in size to 3.5cm or so, and may eat holes in the leaves or even tunnel into unripe fruits. You may find a mature brownish or greenish caterpillar within a fruit. Look out for their droppings on leaves.

It's not a common pest and may not be seen for several years, but keep an eye out for signs of attack. Pick off the caterpillars by hand. You may find they are easier to find in the evening.