This means that feeding tomatoes is unnecessary until the flowers set and small, pea size fruit appear.
An easy mistake to make, if you are new to growing tomatoes, is to give your small plants tomato food. This food is only for tomato plants when they are fruiting and may cause root damage.
If you want to give plants a boost before they begin to fruit I would recommend the following:
- General purpose plant food such as miracle grow at half strength.
- Liquid seaweed extract - a general tonic and very useful when transplanting.
There are other nutrients that may be given such as epsom salts (magnesium sulphate) and extra calcium (to help prevent blossom end rot). However, these should be given with care because sometimes too much of one mineral may prevent a plant absorbing another, especially if foliar feeding.
The thing is not to get too obsessed with feeding tomato plants (as I have done in the past) because if you do, you'll probably give them too much.
If plants have been transplanted into new compost or soil - within the last five weeks - they do not need to be fed.
When transplanting, a half strength feed with general purpose food is helpful (but not essential) because it helps the plants become established in their new home.
Give tomato food (only) when plants start to fruit - little and often is the best way. Professional growers usually feed at every watering, at a reduced strength, so plants alway have access to food.