Clean Roofs, More Light: The Economics of Polytunnel and Glasshouse Roof Cleaning

The Hidden Cost of Neglect

Walk into a polytunnel or glasshouse that hasn't been cleaned in a year or two and look up. Algae, dust, and general weathering create a haze on the covering that doesn't look catastrophic day-to-day, but it is degrading the light reaching your crop.

UK horticultural advisory sources (Growsave, drawing on AHDB guidance) put the effect at up to 10% reduced light transmission from a fouled glasshouse roof versus a clean one, and the same sources point to a well-established industry rule of thumb: roughly every extra 1% of light reaching the crop translates to about 1% more production, particularly in the lower-light autumn, winter, and spring months.

The Math

Take a 1,000m² polytunnel or glasshouse. If dirt on the roof is costing 10% of potential light transmission, you're plausibly leaving a meaningful share of that structure's annual production value on the table, before you've changed anything about your growing practice, just because the covering is dirty.

Why Drone Cleaning Works for This

Speed: a drone-based soft-wash system can cover a typical tunnel roof in a couple of hours, with no scaffolding or access equipment needed. Consistency: a gentle spray pattern means no pressure-damage risk to ageing polythene or glass. Safety: no one working at height. Repeatability: because setup cost is low, a twice-yearly clean (spring and autumn) becomes practical in a way that hiring access equipment for a one-off deep clean usually isn't.

Making It Routine

Roof cleaning works best treated as a seasonal maintenance task, like feeding or irrigation, rather than an occasional deep-clean project. If your roof hasn't been cleaned in over a year, a spring clean is likely to pay for itself in recovered light before the summer growing season is out.

Get in touch to talk through a cleaning schedule for your site.