When Are Hazelnuts Ready to Harvest?

Knowing exactly when to pick hazelnuts is one of the most practically important skills in growing them. Harvest too early and the kernels will be underdeveloped. Wait too long and squirrels, weevil larvae, and birds will have taken everything. The good news is that ripe hazelnuts give clear signals, and learning to read them makes the difference between a full harvest and an empty basket.

Typical Harvest Season

In the UK, hazelnut harvest typically falls between mid-August and early October depending on variety and the season. Early varieties like 'Cosford' ripen from late August; late varieties may not be fully ripe until late September or October. The season can shift by two to three weeks in an unusually warm or cold year. This window is significantly earlier than most people expect — many gardeners wait for October and find the squirrels have beaten them to it by six weeks.

Signs That Hazelnuts Are Ready

The most reliable indicator of ripeness is the colour of the husk. The papery, leafy involucre that wraps around each nut turns from mid-green to yellow-green or pale brown as the nut ripens. At this stage, the husk may begin to open or split at the tip, partially revealing the brown nut shell beneath. The nut itself should be firm and brown — not white and soft, which indicates immaturity. A ripe nut also releases from the husk more easily when gently twisted or pulled.

The Knock Test

Gently knock the branches of the hazelnut over a sheet or tarpaulin: ripe nuts fall easily, while unripe nuts grip the husk tightly and do not fall. This technique lets you quickly collect the ripest nuts while leaving others to develop further. Repeat every few days as more nuts reach full ripeness. In squirrel-pressure areas, this method allows you to harvest incrementally before wildlife takes the crop.

Early Harvesting for Squirrel Protection

If squirrels are a persistent problem, harvesting green nuts in August is a practical compromise. Cut clusters with husks still fully green and spread them in a single layer in a warm, dry place indoors. The kernels continue to develop and the nuts ripen fully over two to four weeks. The flavour is very slightly less intense than fully tree-ripened nuts but the difference is small, and you keep the crop rather than losing it to wildlife.

After Harvest

Spread freshly harvested nuts in a shallow layer in a well-ventilated dry area for one to two weeks to allow any remaining moisture to escape from the shells before storing. Do not pile them deep — poor air circulation leads to mould on nuts that are stored without adequate drying. Once fully dry, hazelnuts store well for months in a cool, airy location.