Crop Thinning of Tree Fruits

AlanGardenMaster
Published on July 7th 2019
22
A close up of a fruit hanging from a tree

Thinning of fruit crops is top of my to-do list. This task will improve fruit quality, and may even prevent branch breakage which often leads to disease infection.

Why thin fruit?

  • An almost frost-free spring has led to a dense fruit 'set'. The spring period, when fruit trees were blooming, is critical to fruit growers and dictates whether there will be a good autumn harvest.
  • Of course, there are factors other than frost that dictate a good harvest of apples, pears and other tree fruits, but this is the key one.
  • You might argue that the prevalence of pollinating insects at this critical time is more important, but a spring frost can ruin even a pollinated baby fruitlets.
Thinning fruits of an apple tree
  • Thinning now will produce better quality and larger fruits at harvest time. Some gardeners have already been thinning apples, but I prefer to wait until the natural thinning process – known as "June Drop" – is over. There's little point in removing a fruit that the tree is going to abort anyway!
  • The June drop is the tree's way of aborting imperfectly fertilised fruits and regulating the crop that it can carry. However, it pays to remove more fruits than this natural thinning process does as the payback will be significantly better quality fruit.
A close up of young apple fruits
  • The fruits I trim off are those that are in any way imperfect. They may be already damaged by a cold night. This shows as a roughening or russeting of the skin. I'll remove fruit damaged by capsid bug, and this shows as a raised bump. I'll also thin any that aphids have had a go at and they'll show as an odd shape or lop-sided.
  • All these fruits are best removed now so that your tree's energies are focused on the fruit that remains.
  • I like to remove all but one pear fruitlet from a cluster but will leave two for an apple.
A close up of a pear fruit hanging from a branch
  • One developing fruit that I always remove is the one that is dead centre in the flower cluster. This is called the 'king' fruit. It has an odd swollen growth by the stalk, but its removal ensures plenty of space for air movement and light to get to those fruits that remain.
A king fruit apple
  • I also target the removal of all fruits that are inside the tree canopy where little sunlight can get to them.
  • Of all the tree fruits, it is especially important to thin out plums where the set is heavy. My experience is that not only will the fruits be smaller and less well coloured if not thinned but significant branch breakage can occur if you don't thin. Plums are heavy fruits!
Victoria plum fruit hanging from a tree
  • Of course, it's important to regulate the crop by fruit crop thinning on a newly planted tree. In its first year, I would remove all but a half dozen fruits so that the tree can get well established before struggling to produce a crop.

Preferred tools

  • I generally use sharp Niwaki hand snips to nip off the fruits by cutting through the stems. For me, this tool is easy to handle for fruit crop thinning.
  • However, you can with care, use a sharp knife or secateurs.
Niwaki snips and apples

Where apples are celebrated

  • On a recent visit to The Newt near Castle Cary, I was intrigued to see the French fruit tree training expert thinning apple fruits by cutting them in half horizontally. Questioning him, he answered that this is a traditional practice handed down through the generations of gardeners in France. After cutting fruits in half, they will then abort. It's argued that this approach is less shocking to those fruits remaining, and as a result, they are less likely to also abort.
Fruits cut in half to thin them at The Newt in Somerset
  • I don't think that I will be changing my technique as this looks a bit of a fiddle! I'll continue to carefully cut through the stem of fruits that I want to remove.
  • But those French gardeners of old knew a thing or two about growing intensively trained fruit trees!
  • This is superbly demonstrated at the newly opened garden at The Newt in Somerset, and I'd strongly recommend a visit! It's the most exciting garden project I've seen for many years!
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