Customer: Haygrove UK 

Location: Herefordshire 

Crop: Strawberries in Hanging substrate gutters 

Tunnel Type: Serra Series - Double Skin Tunnels 

Substrate Gutters: C160 profile with substrate bags 

Fundamental to Haygrove's innovation is maximising the synergy of our farm and growing systems teams by sharing knowledge across specialisms and hemispheres. The collaboration means we can innovate fast and rigorously test products on our own farms to optimise the natural environment for maximum productivity and quality of crop. For the Serra Series Double Skin Tunnel Haygrove are partnering with GeoGroup to supply this poly greenhouse.

Daniel van der Veen, Head of Innovation at Haygrove, explains why Haygrove have chosen the Serra Series Double Skin tunnel as an alternative for a glasshouse to provide season extension on our own Haygrove farm. The aim is to produce 55 tonnes per hectare of strawberries in a double cropping system at the beginning and end of the season when market prices are highest.

The heavy tray plant Malling Centenary crop is planted at the beginning of January, in the UK winter, on a spacing of 12 plants per metre. Each plant is expected to produce about 550 grams. The objective is to pick the crop at the end of March and again in October, at the same time as glasshouse production, and with the same yield, but with a fraction of the capital infrastructure investment.

The tunnels are 9.6m wide with 4 metres to the gutter height. In each polytunnel are 8 rows of hanging substrate gutters for strawberry plants with a middle track to take the fruit to the packhouse. The venting is done through a double butterfly vent at the apex that operates on a rack and pinion system and a roller side vent on one side, both are connected to the climate control computer and operate automatically within the set parameters. 

Studies have shown double skin tunnels are 40% more efficient at retaining the heat as a standard glasshouse without thermal screens. The light transmission in this tunnel uses the latest technology and through both layers is 82%. Haygrove are measuring light levels using sensors placed throughout the tunnels and comparing this to natural light levels outside. The data is stored on the cloud and can be checked monitored on mobile phones and tablets, similar to the technology available in a glasshouse.

The double apex vent and side vents are linked to climate control computer to automate venting based on temperature, humidity, carbon dioxide levels, precipitation, and wind speed and direction to optimise the internal environment of the polytunnel both for yield and pest and disease control.

The Serra series on the Haygrove farm is heated using a gas air heater. If installing over a bigger area, Daniel recommends using heating pipes at ground level for a more even heat distribution making it a more efficient way of managing a consistent climate.