EZvent tunnels at Hall Hunter Partnership, UK

Customer: Hall Hunter Partnership

Location: Berkshire, UK

Crop: Strawberries grown in substrate

Tunnel Type: EZvent

Hall Hunter Partnership are one of Haygrove’s longest standing polytunnel customers, having made their first Haygrove polytunnel purchases over 20 years ago. Today they grow berries across 3 sites in the south-east of England and supply leading retailers with 4500 tonnes of strawberries, 300 tonnes of raspberries and 1500 tonnes of blueberries each year.

Hugh Leach, Agronomy and Trial Coordinator for Hall Hunter Partnership, explains why they are using Haygrove EZvent polytunnels to manage an optimal growing environment on a field-scale. The EZvent tunnels are being used on the Hall Hunter Partnership trial site where they are growing 48 different varieties of Everbearer strawberries, planted at a density of 6 plants per metre. When testing different varieties, climate management is critical to ensure a fair and valid trial is undertaken within the Haygrove polytunnels.

Key benefits Hugh observes from using the Haygrove EZvent tunnels:

The automatic vents mean venting is done at the optimal moment and with sufficient frequency, without accumulating labour costs throughout the season.
20% decrease in fruit wastage in the leg rows from closing the vents to prevent weather damage
High air volume buffers the temperature changes giving more consistent growing environment. With tunnels retaining the heat on cooler days and staying cooler on hotter days, resulting in one-week earlier picking than in their standard polytunnels.

The EZvent tunnels at Hall Hunter Partnership use 8.2m bays with 6 lines of strawberries grown in substrate tabletop system. The support legs are 1.7m above the ground and drilled 1m into the ground. The drill depth ensures that the polytunnels are securely fixed to the ground to prevent them lifting and causing damage. The 1.7m height of support leg places the vents above the crop height meaning there is effective air exchange to maintain suitable temperature and humidity and helps to reduce disease pressure on the crop.

The apex of the tunnels is 5.5m high. The large air volume within the Haygrove EZvent tunnels means there is a slower rate of change to the temperature in the polytunnel. The large air volume combined with Haygrove Luminance polythene, which diffuses the light and provides a thermal heat barrier, there is a more stable growing environment for the plants which reduces stresses and results in a higher yield of quality fruit.

On a hot day, Hugh has witnessed a 3-degree cooler temperature inside the Haygrove EZvent tunnels compared to outside. Yet on colder days the heat has been retained and there has been a 2-degree increase in temperature in the polytunnels. The reduction in temperature fluctuations means the rate of photosynthesis remains closer to the optimum level and therefore plant growth is maximised

The Haygrove EZvent tunnels are connected to a Priva climate control computer. There are sensors inside the polytunnels to measure temperature and relative humidity and outside to monitor wind and rain. The vents on either side of the EZvent tunnel can be operated independently. Wind direction and wind speed is measured so vents can be operated on both the windward and leeward side. The computer is set to automatically operate the vents within set parameters of these variables.

Hall Hunter Partnership has found that compared to manual venting, automatic venting with the Haygrove EZvent tunnels is more accurate with timing and happening with increased frequency, which improves the consistency of the internal tunnel growing environment and allows the strawberry plants to thrive. There is no accumulation of labour costs throughout the season on venting tasks. With manually vented tunnels, timing and frequency of venting is often limited by availability and cost of labour which compromises the yield and quality of the plant.

With automatic windward and leeward venting, the vents can be set to parameters that will prevent damage to leg row fruit. When berries in the leg row are exposed to wind or rain, they can be damaged by knocking into other fruits and rain damage compromises crop quality. At Hall Hunter they estimate a reduction of 20% wastage to leg row fruits. This increases overall yield but also increases picking speeds as labour is not wasted on picking and discarding damaged fruit.

The Haygrove rainwater gutters are made from galvanised steel and have multiple benefits. The automatic vents close when there is precipitation meaning that the leg rows or valleys are kept dry. This protects the fruit in the leg rows and prevents excessive humidity building up in the tunnel. The Haygrove rainwater gutters also mean that when the vents are closed there is a large catchment area for rainwater harvesting which can be collected and stored for irrigation.

Hugh concludes by saying ‘Haygrove EZvent tunnels are a great choice for maintaining the optimum growing environment!’