Thinning Apple Crops to Improve Fruit Size and Quality

Why a heavy set can be a mixed blessing

Every few years an apple tree sets so much blossom that the branches look frosted in May and studded with tiny green baubles by mid-June. It feels like a triumph. In truth, it is often the beginning of trouble. A tree carrying several hundred fruitlets gives every one of them a share of the same limited supply of water, sugars and nutrients, and the result is a crop of small, hard apples hanging like marbles. Branches bend under the weight, bark can split where a limb meets the trunk, and wood that spends the summer exhausted may carry almost no blossom the following season.

Thinning is the answer, and it is one of the oldest skills in British fruit growing. Take off the surplus while the fruit is still small and the tree will pour its resources into the ones that remain. You lose count, but you gain size, colour, flavour and — crucially — a tree that crops again next year rather than sulking into a biennial rhythm.

Reading the June drop

Apple trees do a certain amount of thinning themselves. Roughly four to six weeks after flowering, usually from mid-June into early July, a tree sheds a proportion of its fruitlets: the unpollinated, the weak, the frost-damaged and those chewed by insects. Growers call this the June drop, and it is worth waiting for.

Thin too early and you simply do the tree's work twice. Wait until the drop has settled and the remaining fruit is about walnut-sized. In most of Britain that means late June in the south and milder western counties, and early July further north or in a cold, shaded garden. Thinning within about forty days of full bloom gives the greatest gain in final fruit size, so don't let it drift into August.

The spacing rule that does the work

You do not need to count fruit or weigh anything. Work to a simple spacing guide along the branch, and the tree will do the arithmetic.

• Dessert apples — Cox's, Discovery, Katy, Egremont Russet: leave 10–15cm between fruitlets, roughly a hand's span.
• Culinary apples — Bramley, Howgate Wonder, Grenadier: leave 15–20cm, since each fruit is expected to swell to a heavy weight.
• Cider and perry fruit — Dabinett, Kingston Black, Yarlington Mill, perry pears: 15–20cm for most, up to 25cm on an old, heavily setting tree.
• Clusters — leave one fruit, occasionally two, from each cluster. Never leave three.

Where a cluster holds several fruitlets, keep the king fruit — the central one, which set first, is usually the largest and roundest, and has the best stalk. Twist off the smaller side fruitlets with it. Where the choice is between two equal fruits, keep the one with the shorter, sturdier stalk and the cleaner skin.

Hands, snips and the right moment

For most of the work your fingers are enough. Hold the fruit gently, grip the stalk close to the spur and twist sideways; the fruittlet should come away cleanly with its stalk intact. Pulling straight back risks tearing the spur and knocking off neighbours you meant to keep. A small pair of sharp snips or nail scissors is useful for dense clusters on tight spurs, especially on old, congested trees.

Start by removing the damaged fruit: codling moth entry holes, sawfly scars, scabby or misshapen specimens, and any carrying mildew. These would only drop later or harbour pests. Then work from the top of the tree downwards and from the inside outwards, so you can see what you are leaving. If two fruitlets touch, one of them will rub and scar the other — thin them apart now.

Be cautious with very young trees in their first two or three cropping years. They need leaves and fruit to slow their vigour, so thin lightly rather than hard. On a very vigorous, leafy tree, thinning harder will not encourage growth so much as improve the fruit.

Varieties that need a closer look

Some cultivars are notorious for setting heavily and cropping biennially. Cox's Orange Pippin is the classic offender, and thinning it properly is the single best way to get a decent crop two years running. Discovery, Worcester Pearmain and Katy also over-set and benefit from ruthless thinning. Egremont Russet carries such a heavy load that fruit stays small unless you relieve it.

Bramley is a partial tip-bearer as well as a spur-bearer, so take fruit from the spur clusters but leave the tip-borne apples that form at the ends of young shoots. Cider varieties such as Dabinett and Kingston Black alternate strongly, and a good thinning year often buys you a respectable crop in the "off" year.

Putting the thinnings to work

Do not compost the lot. Unripe apples are full of pectin and malic acid, which makes them genuinely useful in the kitchen and the cider shed.

• Apple jelly — thinned fruitlets set beautifully because of their high pectin. Wash, chop roughly, simmer with water until soft, strain through muslin overnight, then add 450g sugar per 600ml of juice and boil to setting point.
• Verjuice — the tart juice of green apples, used in dressings and sauces in place of lemon or vinegar. Press or simmer and strain, then bottle and keep chilled.
• Cider blending — small quantities of green apple juice add bite and acidity to a bland or flabby ferment. Use sparingly; the sugar is low and the acid sharp.
• Pectin stock — simmer the thinnings, strain, and freeze the liquid in small pots for setting hedgerow jams and fruit cheeses later in the year.

Once the fruit has swelled, you will notice the difference by mid-August: fewer apples, heavier in the hand, better coloured, and a tree still standing proud rather than bowed to the grass. A second, lighter pass in late July is worth it on heavy-setting trees, particularly if the first thinning was done early. Water well in dry spells, prop any limbs that still sag, and you will have done the most useful hour's work in the orchard all year.