Norfolk will be at the forefront of an ambitious planned £1bn investment in soil-free "vertical farming" within the next few years, said a company boss.

Fischer Farms is due to start trial production early next year following its initial £33m investment on a five-and-a-half acre site on the Food Enterprise Park at Easton, outside Norwich.

Tim Smith, general manager of the company’s "Farm 2" operation, said another three vertical farms are planned at the same site during the next two years, backed by specialist investors Gresham House.

Speaking to about 50 members and guests of Holt and District Farmers’ Club, he said this was part of a £1bn planned investment in growing high-quality salads, fruit and vegetables in specialist indoor farms in England in the coming years.

Vertical farms grow crops on stacked trays using hydroponic growing techniques to achieve maximum yields.

Fischer Farms has already built a vertical farm at Lichfield and has also advanced plans for further vertical farming operations near Hull, which will include growing soft fruit such as strawberries and possibly other berries.

Mr Smith updated the meeting on progress at the Norfolk site, where all the main structures have been built, and internal racking will be fitted soon.

The 20 growing tunnels would contain a total of 7,200 trays, each 1.2m by 3.3m. These would be stacked, depending on the state and height of the growing crop, either six high for final growing, or in eights for the nursery stage and twelves during germination.

A range of light spectrums from the 33,000 LEDs would ensure optimum growing conditions. A nutrient formulation would feed the plants, which would be growing on clay-based “peebles,” which would be carefully “scrubbed” after each crop before re-use.

Crops would be grown in a fully-controlled and biosecure environment, which would minimise disease risks and avoid the use of synthetic chemicals including pesticides, herbicides and insecticides.

The strategy for Farm 2’s cropping would begin with a range of leafy-based crops, then in further phases, fruit including strawberries, blueberries may be grown.

Ultimately, it may be profitable to grow soya or wheat in such vertical farming systems, said Mr Smith.

In further phases, he said more robust tunnels would be built, which would enable roof-mounted solar panels to produce more green energy on-site.

Each “vertical” acre was able to produce as much as 250 acres of open cropped area, he added.