How to Grow Tomatoes: A Guide for Successful Crops

Tomatoes are delicious and sweet, and easy to maintain, so who wouldn’t want to grow them? Seeing the juicy red fruits swell is immensely satisfying, and picking them straight off the vine for your lunch will give you guaranteed garden joy.

If you can’t wait to enjoy all this but aren’t sure how to grow tomatoes, we’re here to help with our handy guide. We’ll teach you how to grow tomatoes from seed, how to grow them in pots or containers, and how to plant them in the ground, complete with all the advice you need to make your crops a huge success. You’ll even find a useful video from Rich our Garden Guru, who’ll show you exactly how it’s done.

Sow your seeds between February and April, and plant them out from May to June. This includes whether you’ve grown them from seed and have potted them on, or if you’ve bought a plant that’s ready to go in the ground or its final container. 

As for when you can harvest tomatoes, you can do this from July to September, depending on when the plants were started off.

Tomatoes are easy to grow from seed, as long as you start them off indoors to keep them warm. Sow seeds from late February to mid-March if you have a greenhouse you’ll be transferring them to later (or a grow house, varieties of which you can get specifically for tomatoes). Sow from late March to early April if they’ll be outside. 

Tomato plants like heat so it’s best to use a propagator on a warm windowsill to encourage seedlings to appear, or a heated propagator if you’re worried they may not be warm enough. As long as the temperature is around 18°C, seedlings will most likely sprout within a fortnight. As soon as they do, uncover them and place them in an area with as much sun as possible to encourage good growth.

To learn more about starting plants off from seed, read our guide on how to sow seeds successfully indoors. 

When the seedlings have a couple of true leaves after about a fortnight, transfer them into individual pots. Carefully ease them out of the tray with a pencil or dibber, holding them by a leaf to avoid damaging the stems or roots. Resting the roots on your pencil, place them into ready-made holes in pots filled with multi-purpose compost, and lightly firm the compost around them, making sure the leaves are just above the surface. 

Keep them well watered and in a bright position where the temperature is around 16°C. Leave them here for around a month when it will be time to plant them out into their final position.

Tomatoes are very productive in small spaces, so are perfect for pots. 

Well-rooted tomato plants that are grown from seed and are ready to pot on again, or bought as young plants, can be planted into their final position in early summer, once temperatures are usually above 16°C.

Ease each one carefully out of its pot and place it into a planter or pot filled with compost. Make sure you add enough compost so that the surface of the soil reaches to just underneath the first set of leaves. 

Plant one tomato plant per pot, or two per grow bag. If growing cordon types in a greenhouse, use canes for support. 

If you don’t have a pot or planter for your tomatoes, or a tomato grow bag, a cheap and easy way of growing tomatoes is simply to place your plant into a bag of compost. 

You can keep them in a greenhouse or grow house all summer, or plant them in the ground. If planting outside, make sure they’re positioned somewhere very warm, sunny and sheltered. If in a greenhouse, open the windows often to let pollinators get to the flowers. 

Remember that these tender plants will need hardening off before planting straight out into the garden, which could otherwise shock them. This is a process of placing them outside in their pots every day for a week and bringing them in at night to help them acclimatise to life outdoors.

Tomato plants need a good amount of water to create the juiciest fruits, so water them every day in the summer. If the leaves are starting to curl, this is a sign that your plants are too thirsty. Mulching around the plants will help prevent water loss but leave a space around the bottom of the stem so as to prevent any rot setting in. Feed them with tomato fertiliser every 10-14 days once the first fruits appear for delicious, full-flavoured crops. 

Watch Rich our Garden Guru show you exactly how to grow tomatoes in pots in our video. 

If planting in the ground, make sure you add plenty of compost before doing so. In the warmest, sunniest spot you can find that’s well sheltered from the wind, plant them 45-60cm (18-24in) apart, depending on their final size. Check your seed packet for precise spacings.  

Tomato plants catch diseases relatively easily, compared to other plants, so make sure you plant them in a different patch to the previous year so as to prevent the build-up of diseases in the soil. 

Remember to plant a cane next to cordon tomatoes and tie each plant’s stem to it loosely. Bush types will grow fine without any support.

Just as with potted tomatoes, water them every day during summer as they’re thirsty plants, mulch around the plants to prevent water loss and feed every 10-14 days with tomato feed when the first fruits start to grow.

Now you know how to grow tomatoes, you can get going! Find everything you need for the healthiest plants and juiciest fruits in our garden range, and enjoy the journey to harvesting.