Dealing with a Glut of Raspberries & Blackberries

Raspberries ripen in a rush and blackberries trickle for weeks, so they need different handling. Pick raspberries every day or two at the peak, and blackberries every few days, on a dry day, into a shallow container, and freeze or use whatever you can't eat within a day or two. Picking more often doesn't make either plant produce more fruit, unlike courgettes or beans: it catches each berry at its short peak. The only way to spread a raspberry glut is at planting time, by pairing summer- and autumn-fruiting types. The cane by the fence goes from a scatter of pink to a solid run of dark red almost overnight, and half of what is ripe today will be overripe or gone to wasps tomorrow. A few feet along, the bramble offers a slow trickle of a dozen ripe berries every couple of days, for weeks.

Why raspberries come in a rush

Harvest raspberries when they are richly coloured, plump and easy to pull off. A cane doesn't ripen its fruit one berry at a time: berries that set around the same time in early summer ripen within days of each other, so a bed can go from "a few ready" to "all ready" in under a week. Picking often is damage control, not what triggers new fruit. Overripe raspberries soften and weep juice, and split or overripe fruit draws wasps more than sound berries do.

Pick on a dry day, since damp berries can soon turn mouldy (grey mould), so if a ripe patch is caught between showers, pick it there and then. Net against birds and squirrels, and watch for raspberry beetle, whose grubs work inside the fruit, and raspberry aphid, which spreads virus in the crop. The same damp conditions favour cane blight and spur blight, two fungal cane diseases, which can make a wet year's glut smaller than expected. Picking frequency doesn't change them. Remove spoiled, mouldy or wasp-damaged fruit as you find it: it won't recover and it attracts pests to the rest of the crop.

Why blackberries trickle

A blackberry won't ripen any further after picking, so it must be picked ripe, and the advice is to harvest every few days, taking any fruit that is plump and juicy. Blackberries crop from mid-summer to early autumn depending on the species and variety, a span of weeks to a couple of months, because a bramble keeps producing new ripe berries in small batches for as long as the season runs. As with raspberries, picking more often doesn't increase the crop. Wear gloves, since many varieties have sharp thorns.

Summer and autumn raspberries

Summer types start in June, with later varieties running into September, and autumn types start in August and often run into October. In Scotland the start can be later in a cool year. Grow both and you get harvests for months on end, June to October, instead of one concentrated block. That is a planting-time choice, not something picking habits can replicate. If a bed is one summer variety and the glut is unmanageable, add an autumn-fruiting variety alongside it, or choose summer varieties with staggered ripening, to spread the load. The raspberry growing guide and best raspberry varieties for Scotland cover named varieties.

Blackberries don't split into two fruiting types; variety differences sit within one mid-summer to early autumn window (the hybrid boysenberry ripens around July, for example). An earlier and a later variety can shift the picking window slightly but won't extend the season as much as pairing summer and autumn raspberries. See the blackberry growing guide and best blackberry varieties for Scotland.

How often to check

Neither crop gives much grace once ripe. Check every couple of days at minimum through the peak, and daily in the heaviest week or two, instead of trying to time one big picking session.

Keeping and using the surplus

Both fruits are short-lived once picked. Keep blackberries in a shallow bowl or punnet, only two or three layers deep so the bottom berries aren't crushed, and do the same for raspberries, which bruise even more easily. Use a shallow, uncovered container in the fridge, not a deep bowl or a sealed bag, which traps condensation and speeds mould. A day or two is realistic, so freeze what you can't use by then. Raspberries are best eaten fresh, when juicy and sweet.

For a surplus, freeze them. Both raspberries and blackberries freeze well: rinse gently, dry completely, spread them in a single layer on a tray without touching, and once frozen pack them into an airtight container, which stops them clumping and gives the best quality for up to about 8 to 12 months at 0°F (-18°C). Both also make jam, jelly, sauces and desserts, and jam and chutney from a glut covers the preserving methods.

The Scottish breeding behind the varieties

Timing for both crops is general UK advice, and raspberries are hardy plants that grow well in most locations, especially cooler regions. The Scottish angle sits in the breeding. The James Hutton Institute bred the Glen series, beginning with Glen Clova in 1970, with varieties including Glen Ample (the most widely grown raspberry in the UK), Glen Doll, Glen Lyon, Glen Magna, Glen Rosa and Glen Shee. It used a single dominant gene, A10, to give resistance to four biotypes of the large raspberry aphid that spreads virus in the crop. It is also working on resistance to Phytophthora root rot (Phytophthora fragariae var. rubi), which causes crop losses of around 20% in Scotland. That breeding goes into which varieties end up on sale here, rather than into how a glut behaves.

Common questions

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