Orchard visit: Steve Thomas & Sonia Olykan, Lincoln

Organic walnut orchard

In 2020 – just before the first Covid lockdown – Steve and Sonia took over this walnut orchard that is approaching maturity. The shelter was planted in 2000 and the walnuts were planted from 2003-2007 using the two main crop varieties preferred in Canterbury: Rex and Meyric.

Steve and Sonia explained some of the additional complexity facing walnut growers, such as bacterial blight (which can ruin an entire crop), phytophthora (which can kill mature trees) and the need to harvest nuts within a couple of days of falling, because the weak seal between the two halves of the shell lets moisture and bacteria in.

Blight has severely affected the quality and quantity of their harvests, with the more susceptible Meyric cultivar giving less than half the crop level of Rex (1t/ha compared with 2.2 t/ha). As a certified organic orchard their control options are limited, and they have considered grafting the Meyric over to an alternative cultivar, if only a compelling new variety existed.

Now that the orchard is approaching full canopy, they have noticed the understorey starting to thin out. The clover in particular is an important contributor in their organic management regime, for its ability to fix nitrogen. They’re now starting to remove trees in a grid pattern – this was always the intention, from the time the orchard was planted.

Mature walnut trees