Reports for a commercial glasshouse and packhouse

A commercial glasshouse of any real scale needs a full planning application. Part 6 Class A of Schedule 2 to the General Permitted Development Order 2015 permits agricultural buildings on units of 5 hectares or more, but it caps the ground area of a building at 1,000 m², and a modern production glasshouse with an attached packhouse passes that figure several times over. The application is judged as agricultural development in the countryside, and the two issues that decide it are supplementary lighting and the visual effect of very large spans.

The document list below assumes a glasshouse of one hectare or more with a packhouse, a reservoir for rainwater harvesting, an energy centre and HGV access, on land outside any settlement boundary.

Agricultural policy and the scale question

National policy supports a prosperous rural economy and the development needed to sustain agricultural businesses, and protected horticulture sits squarely inside that. The Planning Statement has to make the agricultural case rather than assume it: the production rationale, why the site and not somewhere else, why this footprint, and what the business does that cannot be done in an existing building.

Scale cuts both ways. A large scheme carries more weight as economic development and attracts more landscape and traffic objection. Where the proposal is phased, apply for what you will build and set out the phasing, because an outline permission for a horticultural complex with reserved matters tends to produce a worse set of conditions than a detailed application.

A large glasshouse scheme may also need screening under Schedule 2 to the Town and Country Planning (Environmental Impact Assessment) Regulations 2017. Do not assume a category applies or does not. Request a screening opinion from the authority and get the position in writing before you spend money on the evidence base, because an Environmental Statement has to be prepared by competent experts and changes both cost and programme.

Supplementary lighting and sky glow

This is the issue that attracts the most objection and the one applicants prepare for least.

Supplementary growing lights running through winter nights turn a glasshouse into a very large luminous object. The effects are sky glow, light spill onto adjoining land and road users, and ecological disturbance along hedgerows and watercourses. A Lighting Assessment should classify the surrounding area into the right environmental zone, model upward light ratio and vertical illuminance at identified receptors, and show the result as an isolux plot.

What makes the case work is the screening strategy. Thermal and blackout screens closed during hours of darkness, with a stated light transmission figure and a commitment to a maintenance regime, do more than any amount of luminaire specification. Offer a lighting management plan for conditioning, with the hours during which screens will be deployed and a mechanism for dealing with complaints. The Planning Practice Guidance on light pollution is the policy reference.

Be honest about gable and roof vents. Screens cannot cover a vent that has to open, and an assessment that ignores vent openings will be picked apart.

Landscape and the visual effect of large spans

A hectare of glass under a Venlo roof reads as a single continuous horizontal plane, and it reflects. That is a different landscape problem from a steel portal frame shed.

A Landscape and Visual Impact Assessment prepared to GLVIA3 should test the daytime reflectivity case as well as the night-time luminance case, with viewpoints on public rights of way and from any receptors on higher ground. Where other glasshouse development exists nearby, the cumulative assessment is the part the authority will concentrate on.

Mitigation that works: siting below a ridge line rather than on it, breaking the mass with internal service corridors and planting belts at scale rather than a hedge, dark coloured gutters and framing, and matt rather than glossy finishes on the packhouse cladding. A Landscape Strategy securing structural planting and a management period gives the officer something conditionable.

Water supply, harvesting and discharge

Protected horticulture is water-hungry and the water case is usually a strength rather than a weakness, provided it is evidenced.

Rainwater harvesting from the glasshouse roof is the normal source, stored in a lined reservoir. Size the reservoir on the irrigation demand profile and a dry-year scenario, and show the balance in the Water Supply Assessment. Where mains or borehole water supplements the harvested supply, an abstraction licence from the Environment Agency may be needed and the water company should be consulted early.

Two things surprise applicants. A raised reservoir holding more than 25,000 cubic metres of water above natural ground level is a large raised reservoir under the Reservoirs Act 1975 as amended, with its own supervision and inspection regime. And nutrient-rich drainage water from a hydroponic system is not clean surface water, so the discharge route, any recirculation and any treatment needs setting out rather than assuming it joins the surface water system.

Energy, heat and carbon

Glasshouses need heat, and the heat source drives both the carbon case and the air quality case.

Set out the energy strategy in an Energy Statement: the heat demand, the source, any combined heat and power, heat recovery, buffer tanks and the use of carbon dioxide enrichment where a combustion source supplies it. Combustion plant above certain thermal input thresholds needs an environmental permit under the environmental permitting regime, so establish the permitting position in parallel rather than afterwards.

Where the authority has a carbon policy, a whole life carbon position may be requested. Glass and steel are carbon-intensive and the honest answer is usually that the operational heat saving over decades carries the argument rather than the embodied figure.

Packhouse traffic and vehicle movements

A packhouse changes the transport case completely, because it brings HGVs, chilled vehicles and shift workers to a rural road.

Where the packhouse floorspace reaches 2,500 m², a full Transport Assessment is the proportionate document rather than a Transport Statement. Cover the daily and seasonal HGV profile, the shift pattern and the staff trip generation, visibility at the access against recorded speeds, the swept path for an articulated vehicle, internal circulation with no reversing onto the highway, and overnight parking so that drivers do not wait on the lane.

Night-time movements are the sensitive point. If chilled dispatch runs between 10pm and 6am, say so and assess the noise at the nearest dwellings alongside the refrigeration plant.

Agricultural land classification and soils

Protected horticulture often sits on good land, and the loss of best and most versatile agricultural land is a material consideration.

An Agricultural Land Classification survey graded by a soil scientist establishes whether the site is grade 1, 2 or 3a. The survey can be done at most times of year but not when the ground is waterlogged, so put it early in the programme. Where the land is best and most versatile, the argument is that protected horticulture is itself agricultural production and that soils under a glasshouse floor are not permanently lost in the way they are under housing. That argument works better when the floor construction and any soil stripping and storage method are described.

Biodiversity net gain applies under the Environment Act 2021 regime, so the habitat baseline needs a growing season survey. The comparison with a livestock building, in the piece on reports for a livestock building on a working farm, is a useful cross-check on the rural evidence base.

Worker accommodation as a separate question

Seasonal labour is part of the business case and is not part of this application.

Accommodation for workers is a separate planning matter, whether it is a caravan site, modular units or a converted building, and it carries its own policy tests, its own site licensing under the caravan site legislation and usually an occupancy condition tying residence to employment in the business. Including it in the glasshouse application tends to complicate both.

Say in the Planning Statement how labour will be housed and transported, because the authority will ask, and an answer that relies on undisclosed on-site accommodation invites a condition preventing it.

This is general guidance, not legal advice. Check the requirements with your local planning authority and read its validation checklist before you submit.

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