Re-Thinning Apples in the Air-Pot Mini Orchard

Back in June, I talked about thinning fruitlets on the apple trees that I have growing in Air-Pots in our back garden. At the time I explained that I’d decided to thin each fruit cluster to just one fruit. The intention was to allow the tree to spread its resources between fewer apples, the net result being, hopefully, larger apples.

Two months on and I’ve taken the decision to re-thin the fruitlets, because they don’t seem to be developing as well as I’d have hoped. On the two trees on which I left around 20 fruitlets – ‘Herefordshire Russet’ and ‘Cornish Aromatic’ – said fruitlets have all grown very slowly and, although it’s still fairly early in the season, they just don’t look as though they’re likely to develop well enough to grow into decent-sized apples in time for harvest in another couple of months:

‘Herefordshire Russet’ Before re-thinning

The third tree – ‘Blenheim Orange'[1] – set fewer fruits, only around 6 or so, and these are developing better than the others, but still not as well as they should. It’s difficult to tell without another apple to make a direct comparison with, but take my word for it: the fruits are a significant distance behind their cousins on the Plot #79 orchard and the cordon trees on our main allotment plot, as well as the heritage orchard at Ordsall Hall. I don’t mind small apples, as long as they’re packed with flavour, but tiny apples with no sugars in them are largely a waste of time and effort.

I suspect the main reason they are so small is simply one of a lack of available nutrients. Even with a regular liquid feed of organic tomato food, plus liquid seaweed tonic, there are bound to be some micro-nutrients that the trees just can’t get hold of. You can tell that they’re not at their happiest by the sparsity of leaves in their canopies, as well as the small size of the fruits. Those few leaves must be really struggling to provide enough photosynthates – mainly in the form of carbohydrates – to meet all the tree’s needs.

So: I’ve removed another 12-15 fruits from both the ‘Cornish Aromatic’ and ‘Herefordshire Russet’, and I’ll be upping the feeding regime for the remainder of the season from once a fortnight to once a week. I’m hoping this will encourage the remaining fruit to grow on a bit more. I focused on removing fruit from branches that had the most fruitlets in total, and from the lower sections of the trees, whose leaves would be most affected by shade patterns in the back garden[2]:

‘Herefordshire Russet’ after thinning (spot the difference..?)

If we get a half-decent crop, then I’ll carry on with this particular growing experiment, although I might see if I can source some larger air-pots so I can re-pot the trees into fresh growing medium next year. But if the fruit remains small, or are generally of poor quality, then I might just knock the experiment on the head and plant the trees out on the allotment instead. We shall see.

How about you? Do you grow any potted fruit trees? What’s your preferred growing medium? Do you have any recommendations as to feeding regime and appropriate plant feeds? Do please let me know, via the comments.

Footnotes

Footnotes
1 Yes, I’m aware that growing a variety like ‘Blenheim Orange’, which is renowned for its great vigour, might be a crazy idea, but crucially, I didn’t know at the time I planted it. And besides, now I’m intrigued – is it viable to do this sort of thing? will the tree’s vigour be channelled into the fruit? – and I want to see what happens…
2 Some of the research I’ve read indicates that photosynthates don’t travel all that far in the tree, so if there’s a strong cluster of leaves attached to a fruiting spur, the fruit on that spur will do better than on a cluster with few leaves, that has to effectively ‘borrow’ its photosynthates from elsewhere

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