An industry on the rise: Nut production in the UK

The up-and-coming nut sector represents a major opportunity for UK farmers to create an additional income stream, but also poses some challenges, according to writer and journalist Kate Hues, who opened the session at the Oxford Real Farming Conference in early January.

A nut grower herself, Ms Hues was keen to learn from the expertise of speakers presenting at the event, and without further ado, offered the stage to Guy Watson, founder of Riverford Organic Farmers.

Raising nut trees in a silvopasture system

A newcomer to the industry, Mr Watson shared his experiences diversifying into nut growing on his organic vegetable farm in south Devon.

The initial plantation consisted of 1,500 hazel and 400 walnut trees, which were established on a 30% slope. However, Mr Watson wouldn’t recommend planting trees on a steeper than 25% slope due to the difficulties in mechanising the process.

Once the trees were in the ground, he placed mulch on top using compost derived from his vegetable enterprise, which resulted in very good weed suppression in the first year, Mr Watson said. He suggested using woodchip as mulch if possible, saying it’s the best material to use with nut trees.

The walnut and chestnut trees on Riverford Farm have been raised as part of a silvopasture system integrating cattle that graze the grass crop underneath the trees. The system allows the trees to be spaced much wider than in more intensive systems, which benefits long-term tree health and productivity, Mr Watson explained.

To protect the young trees and support establishment, spiral guards and electric fencing are used, so the animals can graze right into the base of the trees. Of the 400 walnuts originally planted, 398 are still alive today, which shows the system is working really well, he said.

Meanwhile, a more intensive layout was adopted with hazelnut trees, which were planted in 16m rows. He added that a tighter arrangement might be more suitable for those who farm on good quality soil and are aiming for higher productivity.

Mr Watson was pleased to say that the hazelnut plot had very little damage from wildlife in recent years and the trees have been performing well. Keen to expand his knowledge, he recently visited an intensive hazelnut production site in Piedmont, Northern Italy, where he was somewhat taken aback by the agricultural practices employed by local growers.

According to Mr Watson, the hazelnut fields were ploughed to half a metre deep and suffered significant erosion. Moreover, with the ground was scorched to aid mechanical harvesting, there was very little understory and minimal biodiversity on fields.

In contrast, Mr Watson aims to preserve wildlife habitats in his silvopasture systems and cause as little disturbance as possible. In addition, he plans to install drip irrigation which will soon become a necessity due to the warming climate.

Overall, Mr Watson said nut growing has been a rewarding experience as opposed to annual vegetable growing that requires a lot of cultivation, and encouraged the audience to give it a try.

Nut growing at Kent’s historic Roughway Farm

Next up, Tom Cannon provided delegates an insight into managing a National Collection of nut trees spanning 50 different varieties on his family farm in Kent.

Mr Cannon explained there is a long history in Kent of cobnut production, which is a cultivated variety of hazelnut. Over time, the ‘Kentish cobnut’ even became a variety of its own. Some of the ‘plats’ (short for cobnut plantation) in the area are over a hundred years old and are considered part of the region’s rural mosaic.

The Kentish Cobnut Association, of which Mr Cannon is treasurer, is the leading organisational body for the UK hazelnut industry. Membership is priced at £15/year and grants growers access to meetings, events, workshops, as well as a wealth of resources.

At Roughway Farm, the Cannons grow three main cobnut varieties, namely the Gunslebert, Ennis and Kent. Other varieties grown at the farm include Butler, Cannon Ball, Cosford, White Filbert, Red Filbert, and also various French and German varieties.

Showing an aerial view of the farm, Mr Cannon explained the trees are quite tightly spaced at around 2.5-3m, but are kept small with regular pruning. By keeping the trees under 6ft tall, harvesters can pick fruit without using ladders, he added.

The majority of cobnuts planted in the last 50 years are all single stem at Roughway Farm, with multistem plots boasting a ripe age of 100-150 years. There are also cobnuts found in between plum trees lately so they can benefit from the existing irrigation system in the summer.

Guards are placed on young trees for the first few years and removed once they are well established at age five. According to Mr Cannon, insects are a really issue with hazel establishment, and some species like the stink bug can also impact yield.

While there are no major disease challenges with hazelnut growing at present, he noted powdery mildew is moving across Europe and may soon affect British growers. For those wanting to learn more about pests and diseases in hazelnuts, he recommended the Oregon State University’s Extension Service that has a wealth of information.

Harvest is all manual and therefore quite labour-intensive at Roughway Farm. However, the business benefits from being a mixed crop farm with staff already available picking berries, cherries, apples and plums throughout the season.

Starting in late August, the nuts are picked and put straight into cold storage to preserve their high moisture content. Most of the produce is intended for fresh eating and are packaged green to go on the shelves of Waitrose and Morrisons.

As of late, the Cannons began diversifying into various small boutique products, such as cobnut granola, cobnut chocolate, and roasted nuts. Cobnuts can also be pressed for oil, Mr Cannon said, although he has no plans to produce oil in the foreseeable future.

Being a major nut growing operation, Roughway Farm has featured in shows such as BBC One’s Farmers Country Showdown, BBC Two’s Marcus Wareing’s Tales from a Kitchen Garden, and Channel 4’s Food Unwrapped: Sweet Treat.

Planning ahead is key for a successful nut enterprise

Lastly, walnut and sheep farmer Tom Tame from south Warwickshire shared his expertise and highlighted practical considerations for aspiring walnut growers.

Mr Tame’s main orchard consists of 440 nut trees, including over 20 pecans and hickories, spaced at 10-12m. The walnuts are grown in a silvopasture system with sheep grazing the understory, hence the farm gains ‘two crops for the price of one’.

The majority of harvested nuts are sold as dry walnuts, Mr Tame explained, and some are pressed for oil. Generally, a walnut is 32-38mm diameter and contains up to 80% oil. After pressing, around 55% of oil is recovered, meaning one kilogram of kernel will produce about half a litre of oil, he said.

Approximately 60 different varieties of walnut are grown in the orchard, most of which were acquired commercially, and some are being trialled. Young trees are fitted with a mesh to provide protection from livestock until they reach a height of at least 2.5m.

The trees are also staked as walnut grows very fast – up to 1.5m/year, Mr Tame continued, which can endanger the young tree in strong winds. The guards come off the trees at eight years old, after which the delicate bark is protected with a plastic mesh.

Mr Tame warned that planting seedlings will never produce a viable crop, and grafted cultivars are needed for commercial production. He advised growers to think carefully about cultivar choice and consider:

• Spacing
• Local micro-climate
• Bud break times
• Flowering times – pollination
• End product – whole nut or shelled/&oil

Moreover, Mr Tame explained that although walnuts have both male and female flowers, they are not self-fertile and need pollinator trees to produce fruit. He recommended a ratio of around 5% pollinators in orchards and said most of these trees are now heavy cropping and won’t account for yield penalties.

Regarding irrigation, he uses a low-pressure pipe from a cattle trough to supply trees with additional water for good establishment, long-term health and productivity.

“For us, it’s the only way. If we didn’t do it, we would end up with half an orchard that wasn’t productive,” Mr Tame said, adding that trees that are not well established in the first five years are never going to produce good crop.

While the majority of nuts will fall when they are ready for harvest in the UK climate, the trees still need shaking to complete the process, Mr Tame said. Harvesting is done mechanically at the farm using an Italian chestnut/walnut harvester, which can pick up 2-3 tonnes of nuts a day.

Due to their high oil content, walnuts can spoil quickly if left on the wet ground and should be harvested within 24-36 hours of falling. Ideally, Mr Tame aims to harvest nuts within a couple of hours after shaking the trees, followed by washing and de-husking.

Unwashed nuts can’t be cracked for their kernels as there is a risk of contamination, he added. Once clean, the nuts go on to be dried before being placed into storage as whole nuts or proceeding to the cracking and shelling line.

“We generally crack and shell to press from nuts, we do sell some kernel but it’s too labour intensive and adding cost in. Walnut oil is the only real reason we crack,” Mr Tame explained.

Moving onto some figures, Mr Tame said walnut trees can crop 20-40kg each at 15 years of age in the right climate, provided they’re irrigated and given a good start. The farm sells around two tonnes of fresh walnut at £10/kg each year in passing trade, and could sell a lot more with just a bit of advertising due to the large market, he added.

Mr Tame believes the warmer climate is going to boost nut production in the UK, although trees will require more irrigation going forward. Grass cover also helps retain moisture in the ground, which is one of the many advantages of growing trees in a silvopasture system.

In addition, he reminded growers to think about maintenance and not “plant and forget” as the trees require looking after all the time. Canopies must well-spaced to allow in plenty of light, as nuts won’t grow in poorly lit conditions.

Generally, diseases in walnuts are minimal, with the orchard losing 1-2% of crop in a bad year. However, grey squirrels have been particularly destructive and require constant control, Mr Tame remarked.

Overall, with Britain slowly moving into the commercial walnut growing zone, he says UK growers will soon be able to take capitalise on heavier cropping trees currently prevalent further south.

However, to take a walnut enterprise to success, Mr Tamee said growers must plan ahead and think about their end product, whether they want to harvest mechanically or manually and if they want to press for oil.