Your grow light stays inside, the night stays dark
Assimilation screen systems for greenhouses with supplementary lighting. Keep the light on your crop instead of in the sky, meet light emission rules and stay in control of heat and humidity under the screen. Designed, built and installed by ALWECO.
Light the crop, not the neighbourhood
Supplementary lighting, or assimilation lighting, lets you grow with more light in the dark months and keep quality and production up all year round. But at night, a lit greenhouse without screens glows for kilometres. Neighbours notice it, nature notices it, and more and more governments regulate it.
An assimilation screen, also called a light pollution screen or light abatement screen, is a light-blocking screen installation that closes when the lamps are on after dark. The light stays inside the greenhouse, where it belongs. With purpose-built screen installations and assimilation cloths, ALWECO can bring light emission down to almost 0.1%.
ALWECO has been designing and installing greenhouse screen systems for more than 35 years. We build assimilation installations that close tightly, run reliably every night and fit your greenhouse construction, new or existing.
Why growers choose assimilation screens
Stay within the rules
Many regions set strict limits on light leaving a lit greenhouse at night. A well-sealed assimilation screen is the most direct way to meet them and avoid restrictions on your lighting hours.
Good neighbours
No orange glow over the area and no lamps visible from the road. Keeping the light inside prevents complaints and keeps the relationship with neighbours and local authorities healthy.
Energy saving at night
A closed screen also acts as an extra layer under the roof. During lit nights in the heating season it helps keep heat inside and lowers your energy use.
Light emission rules are tightening worldwide
Wherever greenhouses with supplementary lighting grow, the night-time glow becomes a topic. In the Netherlands, lit greenhouses have had to screen their roofs and side walls for years. In Ontario, Canada, municipalities such as Leamington and Kingsville now require roof, side wall and end wall curtains to be closed at night, and enforce this with fines. More regions are following.
The details differ per country and even per municipality, but the requirements are remarkably similar. The roof needs a light-blocking screen, the side walls and gables must be sealed, and only a limited gap is allowed for ventilation.
We design every installation for the rules that apply at your location, so you can light your crop when it needs it without trouble with neighbours or authorities.
Keep the light in, let heat and moisture out
Lamps produce heat, and a closed screen holds moisture. That is the real challenge of an assimilation screen: blocking light while still being able to ventilate. Our installations are designed for exactly that.
An even gap
ALWECO horizontal assimilation screens are well suited to opening a small, even air or moisture gap, so you can release heat and humidity without letting light escape.
Two installations, one above the other
Combine two screen installations under each other to use every ventilation option to the full: minimal light emission and an optimal climate at the same time.
Baffle screens against cold drop
Cold air sliding down along the walls causes temperature differences in the crop, and with lighting on these can grow even larger. Transparent baffle screens in the ridge stop that air flow.
Assimilation installations by ALWECO
An assimilation system is only as good as its weakest seam. That is why we look at the whole greenhouse: the roof, the side walls, the gables and every connection in between.
Horizontal assimilation screens
Screen installations under the roof with push-pull or wire-pull drive, built with our own Ultra Lock screen profiles and Ultra Delay slip blocks for a complete seal over the full greenhouse surface.
Vertical screens
Roller side wall and twin roller screens that seal the side walls and gables, so no light leaks out along the edges and no lamps are visible from outside. Driven by our own developed or conventional tube motors.
Assimilation cloths
The right light-blocking cloth for your crop, lighting and climate. We help you balance light reduction, moisture transport and energy saving, and take the type of lamps and their distance to the screen into account.
Renovation and retrofit
Switching to more light or to LED? We can renovate an existing screen system or retrofit assimilation screens into your current greenhouse.
Combined installations
Two or three screen installations can share one wire bed or run one behind the other. Block light at night with one cloth, save energy or shade with the other.
Service and maintenance
A screen that has to close every lit night must keep working. We stay available after delivery for inspections, repairs and parts.
We get it done
35+ years
Founded in the Westland, the heart of Dutch greenhouse horticulture.
Worldwide
Design, installation and renovation for any greenhouse construction, anywhere in the world.
Short lines
A small team of specialists, with a screen expert always on the line.
A deal is a deal
Clear quotations, deadlines met and service and maintenance after delivery.
Frequently asked questions
What is an assimilation screen?
An assimilation screen is a light-blocking screen installation in a greenhouse with supplementary (assimilation) lighting. Closed at night, it keeps the grow light inside the greenhouse, so the light benefits the crop instead of lighting up the sky and the surroundings.
How much light must an assimilation screen hold back?
That depends on where your greenhouse is. Rules differ per country and often per region or municipality. In general they require a light-blocking screen under the roof, sealed side walls and gables, and screens closed at night when the lamps are on, with only a limited gap for ventilation. Strict regions such as the Netherlands ask for a roof screen that blocks at least 98% of the light. We check the local rules and design the installation to meet them.
Can I still ventilate when the assimilation screen is closed?
Yes. Our horizontal assimilation screens can open a small, even gap to release heat and humidity. Two installations can also be combined one above the other, so ventilation options are used to the full while light emission stays minimal.
Can an assimilation screen be combined with an energy or blackout screen?
Yes. Two or three screen installations can be combined, stacked on the same wire bed or running one behind the other. That way one installation can block light at night while another saves energy or provides shade. We decide on the best set-up together with you.
Can an existing greenhouse be fitted with assimilation screens?
In most cases, yes. We design assimilation installations for new builds as well as for renovation of existing greenhouses, including the side walls and gables.
Does ALWECO install outside the Netherlands?
Yes. We design and install screen systems for greenhouses all over the world and remain available for service and maintenance after installation.
Planning assimilation screens for your greenhouse?
See all our solutions for preventing light emission and our reference projects on the ALWECO website, or ask one of our specialists for advice and a clear quotation.
Go to alweco.nl