How to grow tomatoes

Martyn Cox

Read gardening expert Martyn Cox on planting, training and feeding your tomato plant to get the best crop.



Whether you want to plant them in the soil or grow them in pots, here’s how to grow your best tomatoes ever.

When to plant

Tomato seeds can be sown under glass in mid-March.

Tomato plants are ready to go into the garden when the first truss of flowers has appeared and when there is no danger of frost in your area - usually from mid-May to early June.

Where to plant

When planting in the soil, choose a sunny, sheltered spot and dig a hole twice the depth of the pot - push a 6ft cane (or a square tree stake) into the ground next to the hole to support the plant.

How to plant

Pop the tomato plant in the hole and plant deeply, allowing the soil to come up to the level of the rounded seed leaves near the base. This will encourage new roots to form and keep the tomato well anchored.

Growing tomatoes in pots and growing bags

If you’re strapped for space, try growing tomatoes in growing bags or pots. Up to three plants can be raised in a growing bag, which can be pushed up against a sunny wall or fence.

First prepare the bag by shaking and kneading to break up any lumps, then form it into a hummock shape. Puncture the base a few times to make some drainage holes and cut out the three pre-marked planting squares. Scoop out compost for the tomatoes to be planted.

The top of the root ball should be beneath the top of the bag and have a covering of compost. Firm in and water.

To keep plants steady, put a growing bag frame over the bag and insert a cane next to each plant.

Single tomato plants are perfect in large (30cm) pots filled with a mixture of John Innes No.2 compost and multi-purpose compost.

Training your tomato plant

Most tomatoes are cordon varieties, where the aim is to grow a single-stemmed plant. To do this, tie in the stem every 10cms with garden twine to its support.

Pinching out

Snap out shoots that grow in leaf joints with your thumb and forefinger - side shoots steal water and nutrients from the plant, preventing it from putting its energy into producing fruit.

Strip leaves from under the first truss of fruit (at the bottom of the plant) when the tiny tomatoes appear. This will allow air and light to reach them, keeping plants healthy and improving the quality of the fruit.

There’s no need to remove leaves from under the other trusses, although you can snip off any that are yellowing.

When your plant has produced four sets of trusses, pinch out its growing tip. This will ensure all of its energy goes into producing fruit. However, if you are growing a multi-stemmed bush tomato, these do not need side shooting. Only pinch the tips to keep plants tidy and within bounds.

Watering and feeding your tomatoes

During the growing season, tomatoes will need watering daily or twice a day in hot, sunny or windy weather.

It’s important that plants never completely dry out as an irregular water supply can lead to blossom end rot, a common problem recognisable by fruit forming a hard, flat black patch.

To plump up the fruit, feed once a week with a plant food high in potash, such as liquid tomato fertiliser, when the first truss of fruit has formed.

The opinions expressed are those of the author and are not held by Saga unless specifically stated.

The material is for general information only and does not constitute investment, tax, legal, medical or other form of advice. You should not rely on this information to make (or refrain from making) any decisions. Always obtain independent, professional advice for your own particular situation.