How to grow tomatoes and best varieties

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

How to grow tomatoes: month by month

Best tomato varieties

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.

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.

When to sow

Plants to grow indoors

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. Mid-March is perfect for tomatoes that will be grown indoors in a greenhouse or polytunnel.

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.

Plants for growing outdoors

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).

Caring for your plants

Planting

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 in a hanging basket

There are varieties that have been bred to be compact and bushy, perfect for growing in a hanging basket. Put one plant in a 40cm-diameter basket and put it outdoors once the danger of frost has past in mid- to late May.

Read more about growing tomatoes in a hanging basket.

Training

Most varieties should be grown as cordons ie only on one stem. Bush varieties are sometimes grown outdoors and these 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.

Feeding

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. If you plant in the ground or in growing bags, feed 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 Buy 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 and when to harvest 

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. 

To pick the fruit, gently lift it 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.

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.

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 growing problems

Leaf curl

Tomato leaves sometimes curl when the temperature is too hot. The plants will still grow so it's not a problem. Try to cool the greenhouse by opening the door and any vents and windows on hot days.

Read more about leaf curl.

Blight

This fungal disease tends to occur in late summer and needs warm, humid weather - you can sign up to Blightwatch for alerts in your local area. 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. It takes very little time for the leaves to be covered, after which they wither and die. The fruits turn a red/brown marbled colour. Avoid wetting the foliage of greenhouse plants as it needs moisture to spread. Unfortunately there are no treatments for it so infected plants should be removed asap. They can be put in the compost bin as blight needs living plant tissue to survive.

Read more about blight.

Split fruits

The fruits can sometimes spilt open, often in varieties with thinner skins, such as cherry tomatoes. The fruit can still be eaten but it may become mouldy if left. Irregular watering is the cause of this problem so try water every day. Outdoor plants are particularly vulnerable as they may experience a sudden deluge in a rain storm.

Read more about split fruits.

Greenback

Sometimes a ring at the top of the fruit remains green and fails to ripen. It tends to occur during hot weather so improving ventilation by opening the greenhouse door and opening vents and windows will help. The fruit can still be eaten.

Read more about greenback.

Blossom end rot

This produces brown, leathery patches at the bottom of the fruit. You can still eat the unaffected parts. It's caused by lack of calcium, which is caused by erratic watering and hot temperatures. Water your plants regularly and help to reduce temperatures by opening the greenhouse doors and any vents and windows.

Read more about blossom end rot.

Tomato moth

This green caterpillar munches the fruits and leaves. Look out for it in the evening when it's most commonly seen and remove any you find. 

Read more about tomato moth.