How to Thin Fruit for a Better Harvest

25 June 2015, written by Benedict Vanheems

When some years ago as a gardening newbie I was advised to cut away and discard half my hard-won apple fruitlets you can imagine my reaction. Horror, disbelief and flat refusal – why, oh why, would I want to do that?! My horticultural superior soothed my troubled self and explained, in a reassuring tone, that by removing fruitlets you are, in essence, improving the quality and size of what’s left.

To those unfamiliar with thinning tree fruits, the process admittedly seems counterintuitive. But Nature herself is also in on the act – sloughing off excess fruitlets so that those left behind have a better chance of reaching the ripening stage. The human gardener just takes this natural process one step further, removing a few more fruits to concentrate on the production of beautiful and delicious fruits of a decent size.

The ‘June’ Drop

Mother Nature completes her fruit thinning in early summer, in a period called the 'June drop'. If you’re reading this in the Southern Hemisphere, I guess you could call it the December drop – but you get the idea!

Nature discards excess fruitlets by severing their lifeline so that they drop to the ground. To the uninitiated it’s a pretty alarming phenomenon, but it’s all perfectly normal. Nature’s priority is reproduction, not the size of fruits, so the June drop is all about maximizing the final count of viable seeds. We’re not concerned with that – we just want juicy succulence to sink our teeth into!

Advantages to Thinning Fruits

Most tree fruits will produce lots of smaller fruits if left to their own devices. By stepping in and carrying out an additional thinning, we can ensure that those fruits remaining are bigger, healthier and better looking.

While the main purpose behind thinning fruits is size and quality, there are a number of other advantages. When left to bear very heavy crops, some varieties can be tripped into a biennial-bearing pattern, where the tree becomes so exhausted that it fails to produce any fruits the following year. It’s also not unknown for exceptionally heavily laden branches to snap under the strain – so there’s an element of risk management going on here too.

Properly thinning fruits will allow more light and air into the canopy, encouraging even ripening and reducing the opportunities for pests and diseases to spread.

How to Thin Fruits

Not all tree fruits need thinning. The usual suspects requiring a trim are apples, plums, peaches and nectarines and, to a lesser extent, pears and apricots. Every tree is different, but there are some general guidelines that will help you to get the best results.

Apples: Start by removing any malformed or otherwise suspect-looking fruitlets; only the best-looking fruitlets go through to the next round! You should also remove the ‘king’ fruit, which lies at the center of each cluster, plus any fruitlets that are poorly positioned. Now thin out those left behind so that there’s one fruit every 10-15cm (4-6in) for dessert/eating varieties and one fruit every 15-23cm (6-9in) for culinary/cooking varieties. Use secateurs/pruners or long, sharp scissors to cut away the fruits. Or with a little practice just tug the fruits away between your thumb and forefinger.

Plums: These guys are among the most energetic of all tree fruits, so you’ll definitely need to flex the fingers and get thinning. Pick off excess fruits between finger and thumb, leaving 5-8cm (2-3in) between smaller fruits or one pair of fruits every 15cm (6in).

Peaches and nectarines: Start thinning peaches in spring when they are the size of a hazelnut to leave 10cm (4in) between fruitlets. Then complete a further thin once they reach walnut size – to 20-25cm (8-10in) apart. Nectarines are thinned in one go at walnut size to 15cm (6in) apart.

Apricots: No need to thin unless a particularly heavy crop is on the cards, when the young fruits should be thinned to 5-10cm (2-4in) apart according to the size of fruits required. Thin the fruits when they are the size of a hazelnut.

Pears: They need less thinning than apples, though you’ll still get a better-quality crop if you take the scissors to them. Thin the fruits to leave two per cluster at 10-15cm (4-6in) apart. If the tree looks like it’s on course for a very heavy crop, be a little more selective, thinning to one fruit per cluster.

So be brave – not to say ruthless – and thin your tree fruits. It’s for the best, I promise!