Hazelnut Care Calendar

The dormant season, from leaf fall to bud swell, is when structural work happens. The bush is asleep, the framework is visible, there is no crop to damage and machinery does not harm new growth, so pruning, sucker removal, dormant-season spraying, soil sampling, drainage and track repair and equipment servicing all belong here. It is the only stretch of the year with slack in it, and work postponed out of it tends to be work that never gets done.

Spring is a sequence of narrow windows that open in a fixed order: bud swell, then flowering and pollination, then bud burst and shoot growth. The first half of the nitrogen goes on as buds swell in mid-March; the pruning window closes as they burst; the bud mite, shoot moth and gall midge treatments each have their own moment in the same few weeks. Miss the order and you cannot recover it, because the plant does not wait.

Summer is about water, monitoring and the crop. June and July are the critical irrigation period and the kernel-filling phase, which is also when potassium support and leaf sampling belong; nitrogen stops after July so the bush can harden off for winter. Harvest runs from mid-August, followed immediately by threshing and drying. Autumn then reopens the cycle: the post-harvest copper spray before the rains, soil analysis in September-October, liming in November if the pH calls for it, and pruning beginning again from November.

In full dormancy hazelnut is remarkably tough, tolerating temperatures down to around -25°C. That resilience disappears as soon as the plant starts to move. The frost protection guide gives the thresholds that matter: male catkins are killed completely at -8°C and female flowers at -16°C, and once shoot and fruit development is under way damage begins below 0°C. Which is why a mild February is not automatically good news - early bud break simply moves the vulnerable stage into the part of the year when frosts still happen.

Flowering comes early and is easy to miss. In February the male catkins hang down and shed pollen into the wind while the reddish stigmas of the female flowers become visible on the buds. Hazelnut is wind-pollinated, so there is no insect activity to alert you and nothing to do except confirm that pollen is being released and that the orchard contains adequate pollinator varieties - inadequate pollination shows up much later as an increased proportion of empty nuts.

After bud burst the sequence runs through shoot growth and fruit set in spring, kernel filling through June and July, and ripening from August. Ripening is judged by the husks: browning, tips curling open, nuts loosening and the first natural drop. Every one of those stages is a better trigger for action than a date, and every one of them shifts a little from season to season.

Harvest dates make the geography obvious. Coastal Ordu starts earliest, around 5-10 August; coastal Giresun around 10-15 August; Trabzon from 10-15 August with harvest continuing into early September; Düzce and Sakarya from 15-20 August into early September; and high inland orchards from 20-25 August through to mid-September. Altitude, climate and variety together account for a shift of one to three weeks in either direction, and the same shift applies to every other job in the calendar, not just harvest.

Altitude changes risk as well as timing. Higher orchards have a narrower pruning window between hard frosts, later bud break, and markedly more branch canker, since the cool, humid conditions that favour the fungus are more common with elevation - the branch canker guide advises against planting susceptible cultivars such as Fosa and Mincane above about 300 m and recommends cold-hardy alternatives instead. Late spring frosts and hail also cause more wounding at altitude, which feeds back into disease pressure the following season.

Within a single orchard the microclimate matters too. Cold air is heavy and pools in hollows, creating frost pockets, while sloping ground with good air drainage escapes the worst of it and south-facing slopes warm earlier. If part of your orchard consistently runs a week behind the rest, or is consistently the part that gets frosted, that is the geography talking - and it is worth building into your working calendar rather than fighting.

Keep records. Write down the date buds began to swell, when the catkins shed pollen, when the first symptoms of anything appeared, when you sprayed and what the result was, and the date harvest started. After two or three seasons you will have your own calendar, offset from the published one by a known number of days, and that offset is worth more than any general guide because it is measured in your orchard rather than in an average one.

Add instrumentation where it is cheap. A minimum-maximum thermometer in the orchard tells you what the overnight low actually was rather than what the regional forecast said, and following frost bulletins from the provincial and district agricultural directorates gives you warning to act. Clear nights with low humidity and still air are the classic frost signature. The frost protection guide covers what to do once the warning arrives.

Finally, confirm anything that is legally or biologically tight with someone local. Region-specific dates for dormant-season spraying and for the shoot moth window, and the list of currently licensed products, both come from your provincial or district agricultural directorate. Use the calendar to know what is coming and to have the equipment and materials ready in advance; use the bushes, the weather and local advice to decide the exact day. The care and pruning, fertilization, disease and pest guides fill in the detail behind each entry.