We use cookies to allow us and selected partners to improve your experience and our advertising. By continuing to browse you consent to our use of cookies. You can understand more and change your cookies preferences here.

Home & garden.

When you click on a retailer link on our site, we may earn affiliate commission to help fund our not-for-profit mission.Find out more.

Updated: 23 May 2022

Best tomato feed

Ensure a bumper harvest this summer with one of our Best Buys
Ceri Thomas
Feeding tomato plant

Tomatoes are one of the most popular vegetables to grow, and if you want to pick the biggest, tastiest crop it’s essential to feed your plants. 

The nutrients in compost or a growing bag will last for only four to six weeks. And even controlled-release fertilisers have a lower level of potassium – essential for fruit development – than tomato feeds, and will be running low by the time tomatoes are ripening. 

Using a good liquid feed will give you sweet, ripe tomatoes for longer than controlled-release fertiliser alone, so we set out to see which of the currently available products will do the best job. Tomato feeds are also great for feeding pots of flowering patio plants, such as petunias and begonias.

Learn more about how to grow tomatoes.

Make more of your garden - get our free Gardening newsletter for top tips from our experts

Which? Gardening Magazine

Expert advice through the seasons so you know what to do and when. £4.99 a month, cancel anytime.

Sign up now

Best tomato feeds

ProductWhat we foundTest scorePrice
This produced the largest yield of ripe tomatoes in our trial with a whopping 14.3kg from three plants. True to its name, it’s ready to use and doesn’t need diluting. Simply pour it on to the compost at a rate of two 50ml capfuls twice a week (once the second truss of fruit has formed),followed by 500ml of water each time. It’s ideal if you have only a few plants and don’t want to waste feed you’ve diluted.75%£7.99 for 3L
Our plants fed with this feed gave us 11.6kg of uniformly sized, ripe tomatoes; we also picked 1.8kg of healthy green tomatoes. You need to use this feed every four or five days after the first truss of fruit has set, diluting half a capful (20ml) in 4.5L of water and using 500ml per plant. It’s a good bet if you have lots of tomato plants to take care of.72% £5.99 for 1.25L

Full results for tomato feeds

ProductDosageOverall scoreYield red fruit (kg)Yield green fruit (kg)YieldFoliage vigourFruit qualityEase of use
100ml per plant75%14.30.6
20ml in 4.5Lwater


20ml in 4.5L water

1st truss weekly; twice a week at 2nd truss; then every watering
Once a week52%9.31.5
Once a week49%9.21.5

USING THE TABLE The more stars the better. Yields are healthy fruit from three plants. OVERALL SCORE Ignores price and is based on: yield of tomatoes 50%; foliage vigour 20%; fruit quality 15%; ease of use 15%.

When to feed tomato plants

Adding a controlled-release fertiliser to your compost at planting time will provide your plants with the nitrogen, phosphorus and potassium (NPK) they need for healthy growth, but they may well be running low by the time your tomatoes start to ripen. If you haven’t added a controlled-release fertiliser, you should start giving your tomatoes a liquid feed once the first truss of fruit has formed. 

Discover our best controlled-release feeds.

How often should you feed tomato plants?

Most products need to be applied at least once a week, with the frequency sometimes increasing once the second truss of fruits develops; check the dilution and frequency on the product label.

Is tomato feed good for all plants?

Tomato feeds aren’t just for tomatoes; most have more potassium in relation to the nitrogen and phosphorus, which helps to promote flowering and fruiting. You can therefore use a tomato feed  on any container-grown plants that produce lots of flowers or fruits, such as fuchsias, clematis, aubergines, cucumbers, peppers, courgettes and chillies

How we test tomato feeds

  • The researchers for Which? Gardening magazine selected eight widely available tomato feeds to test, plus one specialised compost that doesn’t require feeding.
  • In mid-April we potted up tomato ‘Shirley’ plants in a Best Buy peat-free compost to provide three plants per feed treatment, then planted these into their final 10L pots in mid-May using the same compost.
  • For the specialist compost on test, we potted up tomato plants into 10L pots of this compost.
  • We began feeding our tomatoes in mid-June at the rates described on each product. The plants in the specialist compost were given only water.
  • We grew our tomatoes as cordons in an unheated polytunnel, stopping the plants by pinching out the growing tip after six trusses of fruit had formed.
  • We rated the vigour of the plants, and the quality and yield of fruits for each feed. We also rated each product for ease of use.