Pruning Tomatoes for Growth and Taste

Now is a good time to think about pruning – bush varieties don’t need pruning but tall varieties do. This is the way I like to prune my tall (aka cordon and indeterminate), tomato plants.

Leaf Pruning – please read carefully before chopping!

It’s a good idea to remove leaf branches up to the first truss when the first truss has started to set fruit. However, it is important to understand that the closest leaf branch to each truss of fruit, provides the tomatoes on that truss with the energy they need for growth and taste.

Pruning tomatoes for growth and taste.

In other words, each leaf branch provides energy for its nearest truss.

This is important to keep in mind when we are removing leaf branches if we want maximum growth and taste.

Remove the middle branch when plants are too vegetative (leafy)

For example, if there are three leaf branches between the first and second trusses, the best way to prune is to remove the middle leaf branch, leaving the branches nearest the trusses.

It’s good to keep leaf branches below and above each truss as the fruit are swelling, but once the tomatoes have begun to ripen, all the leaf branches up to that truss can be removed.

We want energy to go into fruit production – not making a lot of leaves!

Leaves below the first truss

Below the first truss, leaves lose their colour early because the growing tip removes their nitrogen and magnesium etc. – the growing tip gets preference! All the leaf branches can be removed (gradually) up to the first truss when the tomatoes on the first truss have started to set fruit.

The second truss and above

Removing all of the leaf branches up to the second truss can be done when the fruit on the second truss is ripening (not just setting). In other words, leaf branches can be removed up to the truss that is producing ripe fruit.

By this time, the ripening fruit will have received plenty of sugars from their nearest leaf branches.

Four of Five Trusses Outside

If you are only growing four or five trusses, I wouldn’t worry too much about removing all branches up to the ripening truss – just remove leaf branches up to the first or second truss, middle leaf branches as fruit are swelling, and trim long leaf branches if necessary.

You may wonder why we need to prune at all?

It’s because we need to keep a balance of leaves/fruit and keep a plant producing enough energy from the leaves to supply to the fruit.

Tomato plants have two phases of growth

  • The vegetative phase – producing the stems and leaves etc.
  • The generative/reproductive phase – producing the flowers and fruit .

The plant begins its life in the vegetative phase and when flowering and fruiting begins, it moves into its reproductive phase.

However, these phases are not mutually exclusive – in the second phase of flowering and fruiting, we still want plants to be growing stems and leaves to support higher trusses, but the main objective is to provide enough energy for the continued growth of the plant and tomatoes over a given period of time. This means that a balance of vegetative and reproductive growth is required.

This is where pruning comes in … also known as plant steering.

We want to direct energy from the leaves to the fruit. We don’t want to create a lot of big luxurious fat juicy leaves that when they get a bit older will become a drain on the plant’s energy and reduce the amount of tomatoes we get! By the way, tomato leaves are poisonous – don’t eat them!

Check your trusses

One way to tell if your plants are too vegetative (apart from having lots of leaves) is by the position of the trusses.
If your flower trusses are pointing upwards, the plant is probably too vegetative. If a truss is roughly at 90 degrees, that shows a balanced growth.

Leaves in shade are less important

For example, if you are growing plants up against a wall or fence, the leaves at the back will be producing much less energy for the plant than those at the front in direct sunlight, so shaded leaves can be removed (as long as there are enough leaves at the front of course!).

Feeding large tomato varieties

If you’ve ever tried to grow large tomato varieties that run out of steam at the second or third truss, it’s probably because the vegetative and reproductive balance needs adjusting. We tend to overfeed with with potassium (tomato food) too early which slows growth and encourages ripening. Using a balanced feed will help keep growth in the upper trusses.

The method above is the way I prune and feed my tomato plants. There are no rules set in stone but by following a few tips about pruning, you should improve both the growth and taste of your tomatoes.

Another week has past and tomatoes are on their way!

Cheers,

Nick

16 Responses

  1. Derek R
    | Reply

    Hi Nick. I don’t contribute much but just to say ; that after describing to you my chosen process and first attempt to grow Tomatoes through to Xmas 2016… Firstly I picked my last tomato on the 31.12.16. Secondly, Last years plants started cropping on 16.06.17 I did it in a cool Greenhouse powered with Compost but needed a small electrical heat source when my ineptitude at maintaining my Composter showed me up twice during last winter. I only need three plants as they are now well over 6ft tall and just beginning to crop this year. Last year my Crimson Crush plants grew beyond 12ft, cropping from May onward
    I live in the Tyne Valley so would not usually expect to begin cropping until late July.

    Derek Robson

  2. Rhys Jaggar
    | Reply

    aahhhhh – blossom end rot arriving on San Marzano and Black Krim despite constant attention to feeding and watering.

    Interestingly, it is only emerging on the recently set young fruit – the larger more mature fruit are free.

    I can only assume it is due to the extreme heat – it has been well over 80F for five days now.

    I am wondering whether to eliminate certain strains from my growing plan based on susceptibility to BER.

    • Nick
      | Reply

      Hi Rhys, that’s a good idea to avoid the varieties most prone to BER. I once grew a lovely Yellow Pear variety and every tomato was effected. The plum varieties with the most flesh are very prone to BER and of course the heat makes it more challenging to avoid too – as you say.

  3. Sue Heyer
    | Reply

    Hi Nick, I’ve been following your excellent advice for years, but now have a question. I’m growing Berner Rose (cordon) for the first time this year (it’s a local variety as I live in Switzerland). They are growing in a 50cm high raised bed under a tomato shelter open to the Southeast. I’ve removed the lower leaves up to the first truss as advised, but all the other leaves are a good 40-50cm long, so I’ve cut the longest ones back by about a third to let more air through. Do you think this is ok?
    Best wishes
    Sue in Switzerland

    • Nick
      | Reply

      Hi Sue, It’s good to hear from you!
      Leaf trimming is perfectly OK – it’s much better to have good air circulation around plants that are close together, than to have long leaf branches and diseased leaves.
      Kind regards,
      Nick

  4. Jessie Allaway
    | Reply

    Hi Nick, I was looking back to a previous article checking your advice on blossom end rot when I noticed a comment by someone on Growth Technology. Have you ever tried their plant food and, if so, what was your opinion? Best regards, Jess.

    • Nick
      | Reply

      Hi Jess, I have tried it and it is as good as any of the other nutrients available for hydroponic growing.
      I used to attend the trade shows and get samples from a wide range of products. One thing I found out is that there isn’t much difference in results between the least expensive and the most expensive nutrients – it’s the way we use them (how much and when) that makes a difference. Kind regards, Nick

  5. Rhys Jaggar
    | Reply

    This is a fantastic description of the balances needed between leaves and trusses for the next six weeks. I think I just about worked this out over the years but this summary really is ideal.

    This year my distance between trusses is much smaller and flowering really is more rapid too, particularly on Alicante, Tigerella and Black Russian. I removed leaves up to the first truss late May on the March sowings and nothing really since. April sowings are now in flower but no tomatoes set yet. I just assumed the ideal temperatures we have had up here were the reason for all the trusses so close together, but maybe optimal pruning helped….

    My experience with beefsteaks is that they often set a lot but not all grow big, notably Black Krim and Black Russian (often some start growing in late July once the first fruit reach mature size). Super Marmande just seems to keep on going, giving 30-40 fruit from one pot. They certainly have a different titration profile for potassium than traditional salad tomatoes…..

    • Nick
      | Reply

      Hi Rhys, thank you for your words of appreciation – as usual.
      I’ve found that the distance between trusses and leaf branches usually depends on the amount of light received. A good sunny spring and early summer and trusses are closer together and flowers more numerous. I think that pruning also helps, as more energy is directed to where it is needed.

  6. Rob
    | Reply

    Hi Nick,

    Thank you for your superb guide to pruning. You’ve answered questions I didn’t know I needed to ask! I always wondered why the trusses pointed upwards in some years and outwards in other years. I used to put it down to the weather!

    • Nick
      | Reply

      Hi Rob, I’m pleased you found the newsletter helpful – It’s amazing how much there is to learn about tomato plants!

  7. David Clarke
    | Reply

    Hi Nick just reurned from holiday to find the new growth on some of the tomato plants have gone yellow. They have have been watered whilst I was away but not fed. Can you offer any advice and will they recover?
    Regsrds

    • Nick
      | Reply

      Hi David, by new growth I assume that you mean leaves at the top of the plant – the growing tip. When this happens it is usually a calcium or iron deficiency. When old leaves lower down turn yellow it is usually a nitrogen or magnesium deficiency.
      Plants do recover if sprayed or soil fed with Chempak Calcium or Iron nutrients – you could try foliar spraying with 50-50 skimmed milk-water. Spray the underside of leaves for quickest results and see if that works. Don’t use full fat milk because it will cause infection as the fat degrades.

      • David Clarke
        | Reply

        Hi Nick yes it was new growth at the tip and I have followed your advice regarding spraying. Like other people who have contacted you regarding removing leaves I have also learnt alot. Just waiting to taste the first tomato!

  8. Valerie
    | Reply

    Thank Nick for a most useful description for checking leaves and fruit.
    My tomatoes although late are coming on nicely in Quadgrows and just coming into flower.I am using the Yoyos for the first time and my green house looks much tidier!

    • Nick
      | Reply

      Hi Valerie, I’m pleased that you have found the Yoyo’s useful – they also work well for supporting those heavy trusses of tomatoes!

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