Harvesting Plums at the Right Stage of Ripeness

Why Plums Refuse to Ripen All at Once

Few things disappoint a grower more than a basket of plums picked a week too early — hard, mouth-puckering, and stubbornly unwilling to sweeten properly once off the tree. Equally frustrating is the tree that drops half its crop onto the grass overnight while you were waiting for "the right moment".

The truth is that plums ripening in a British garden rarely offer a single perfect picking day. A mature Victoria, Czar, Opal or Marjorie's Seedling will crop over three to six weeks, with fruit on the sunny south side of the tree ripening first and the shaded inner branches lagging behind. Learning to judge each plum on its own merits, rather than judging the tree as a whole, is the single most useful skill you can develop. Pick over your trees every two or three days through late July, August and into September, and you will harvest far more usable fruit than if you wait for a grand, single gathering.

Read the Colour, but Know Your Variety First

Colour is the first clue and the easiest one to misread. Every variety ripens to its own final shade, and that shade is not always the one on the label at the garden centre. A useful starting point:

• Victoria — dull red over a yellow-green ground, deepening to a rich reddish-purple with a pale bloom.
• Czar — dark purple-black, ready from early August and notably good for cooking.
• Opal — a reddish-purple flush spreading across a yellow background, usually the earliest of the familiar garden sorts.
• Marjorie's Seedling — blue-black and late, often hanging well into September in good conditions.

Ignore the fruit's darkest cheek and look instead at the ground colour around the stalk. When green gives way to yellow, then to the variety's true hue, you are close. Fruit that is still hard as a pebble at that colour wants another few days.

The Palm Test, the Bloom and the Stalk

Colour tells you it is nearly time; touch tells you it is time. Cup a plum in your palm and press gently with your thumb against the side of the fruit. A ripe plum gives slightly, with a little spring, much like a ripe avocado. If it is rock-hard, leave it. If your thumb sinks in and leaves a bruise, it is past eating fresh and belongs in the jam pan.

Two further checks are worth knowing. Ripe plums carry a dusty, waxy coating called the bloom; it rubs off with a light finger swipe, and where it has weathered away naturally the skin beneath is glossy and full-coloured. Then try the stalk. A ripe plum comes away with a gentle twist, leaving a clean, small scar and often a short piece of stalk attached. An unripe one needs a tug, and you will frequently pull a scrap of spur wood with it — never a good sign for next year's crop. Bruised or split fruit should be gathered at once, whatever its stage, since wasps find the smallest crack within hours.

Picking Ahead of the Weather

British summers being what they are, the last week of ripening is often the wettest. Plums take up water fast through their roots, and heavy rain after a dry spell splits fruit along the seam almost overnight. If a soaking is forecast and your plums are within a few days of ripe, pick them. Slightly under-ripe plums finish perfectly well indoors on a tray, and you will lose far less to splitting, brown rot and wasps.

Birds and wasps are the other reason to pick early. Once the first fruit in a cluster is pecked, the whole truss becomes a target. Gather the ripest few, leave the rest to swell, and return in two days.

Storing and Finishing the Crop

Plums store better than most soft fruit if handled with a little care. Keep the stalk on, never wash fruit you intend to keep, and lay them in a single layer in shallow trays or a fridge salad drawer. A cool shed, garage or unheated room will hold firm fruit for one to two weeks; the fridge stretches that to three. Discard any bruised or split fruit immediately — one rotting plum will spoil its neighbours.

• Under-ripe, firm fruit — ripen on a sunny windowsill or beside bananas, or use straight away for chutney and pickle.
• Just ripe — eating, tarts, crumbles and freezing, halved and stoned on a tray before bagging.
• Fully ripe and soft — jam, fruit leather and bottling; a proportion of slightly under-ripe fruit helps jam set.
• Overripe — straining for jelly, fruit wines or blending into a country cider or perry-style brew for a tart, fruity edge.

Home cider makers have long used plums in small quantities alongside apples, adding a sharpness and stone-fruit aroma that turns a plain brew into something memorable. Use no more than a tenth of the must as plum, and choose ripe, clean fruit. Whether your harvest ends up in a bowl on the kitchen table, a jar of jam or a demijohn in the airing cupboard, picking at the right stage is what makes the difference between a crop you tolerate and one you are proud of.