How, Why and When to Prune Tomatoes
Questions asked about pruning tomatoes include :
- Why do you need to prune tomatoes ?
- How do you prune tomatoes ?
- Are all types pruned the same way ?
Here Are the Answers
ALL Tomato plants should be pruned to lift them up off the ground and create healthier plants.
As they get taller ALL tomatoes will naturally grow along the ground because they simply fall over with weight of foliage and fruit.
Basic Pruning for Healthy Growth
Tomato plants growing on the ground are prone to disease and pests so all tomatoes need to be pruned and staked.
The lower foliage should be pruned off so that it does not touch the ground. We prune at least the bottom 30cm (12 inches) of foliage and all laterals as the plant grows.
Pruning the lower growth from the plant stops the leaves coming into contact with the soil, so fungal diseases are less likely.
After removing growth close to the ground it depends on the type of tomato that you are growing as to whether you prune them further or not.
Tomatoes are divided into two types, indeterminate types and determinate types.
- The determinate types are smaller growing bushes they reach around 1 metre (4ft) in height and the fruit ripens at around the same time and then the plant dies back.
- If you prune these types more than lifting foliage off the ground, you will reduce your crop size.
Pruning Indeterminate Types
The indeterminate types grow like vines. They keep growing, putting out new growth laterals and flowers which means fruit continues to grow and ripen until it gets too cold (frosts).
These are the ones that are pruned right through the season if you want to increase production
You do not have to prune them, however if you do prune them you will increase yield and this is because you can plant them closer together, so more plants, and therefore more tomatoes.
We plant our tomatoes at around 12 inches (30cm apart, we either stake them or grow them up strings.
What part do you prune ?
What you are pruning are the laterals, sometime called suckers.
These are the laterals, the new growth shoots that appear from where the leaf shoots appear on the stems. You can pinch them out as they appear or use secateures.
Pruning increases air flow, which helps prevent disease, and allows us to increase the amount of light that reaches the plant and fruit. And if you are planting at 12 inches (30cm apart.) this is essential.
How does Pruning Increase Yield
On an individual plant, pruning will decrease yield by around 10%.
HOWEVER, as you can plant 2 – 3 times more plants so overall yield increases.
Pruning out the laterals also focuses the plant on producing more flowers, more flower more fruit. and it also speeds up the ripening of the fruit and usually leads to larger fruit.
When do we Prune Tomatoes ?
- We prune continually with the indeterminate
- With the determinate types as soon as the they are tall enough to allow us to clear the lower 12 inches, 30cm.
NOT all indeterminate types are tall growers, San Marzano is lower growing.
Recommended Indeterminate types include:
- Periforme abruzzese (Piriforme abruzzo)
- Grosse Lisse
- Rouge de Marmande
- Costoluto Fiorentino
- Beef Steak
- Amish Paste
- Mortgage Lifter
- Tommy Toe