Total darkness, exactly when your crop needs it
Blackout screen systems for cannabis greenhouses. Control the photoperiod to the minute, keep grow light inside at night and hold a stable climate under the screen. Designed, built and installed by ALWECO.
Flowering on your schedule, not the season's
Cannabis is a short-day plant. It switches to flowering when the night is long and truly dark, and even a small amount of stray light can disturb that process. In a greenhouse, daylight and the seasons decide how long the night is, unless you take control.
A blackout screen closes the greenhouse off from outside light completely. That lets you create a long, uninterrupted dark period on any day of the year, start flowering when you choose and plan harvests all year round.
ALWECO has been designing and installing greenhouse screen systems for more than 35 years. We build blackout installations that close tightly, run reliably every day and fit your greenhouse construction, new or existing.
Why growers choose blackout screens
Photoperiod control
Close the screen to create the dark period your strain needs, every day, regardless of sunset times or the time of year.
No light pollution
With assimilation lighting on at night, the closed screen keeps the light inside, which helps you meet local rules and stay on good terms with neighbours.
Stable climate
A closed screen acts as an extra layer. Combined with the right ventilation strategy it helps you manage temperature and humidity under the screen.
Blackout installations by ALWECO
A blackout 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 blackout screens
Screen systems under the roof that close the full greenhouse surface. Available with two or three layers of cloth, so blackout can be combined with shading and energy saving in one installation.
Vertical blackout screens
Side wall and gable screens that seal the vertical surfaces, so no light leaks in or out along the edges of the greenhouse.
Screen cloths
The right blackout cloth for your crop and climate. We advise on the cloth that fits your goals for darkness, moisture handling and durability.
Renovation and retrofit
Already growing? We can renovate an existing screen system or retrofit blackout screens into your current greenhouse.
Screen shading for cannabis greenhouses
Interior shade screens give your crop shade during the day and help you conserve heat energy. Combined with a blackout layer, one screen installation does both jobs.
Shade by day, heat at night
The screen provides shade when the sun is strong. Closed at night during the heating season, it keeps heat inside and saves on heating costs.
Maximum light when cloudy
On cloudy days the screen is retracted, so your plants receive the maximum available light for photosynthesis.
Less leaf condensation
Shade screens reduce condensation on the leaf surfaces, helping you keep a healthier crop.
The right weave for your greenhouse: we recommend an open weave for greenhouses with natural ventilation, and a closed weave for pad and fan cooled greenhouses.
Ultra Tight Profile: seals any greenhouse
Total darkness depends on a tight seal. With our own Ultra Tight special closing profile, ALWECO can seal a greenhouse virtually completely, whatever its style, new or existing.
The profile is ideally suited for poly greenhouses and can be used in greenhouses with or without trusses, also where additional systems need to be mounted on the truss. Whatever your situation, we have a solution.
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
Why does a cannabis greenhouse need a blackout screen?
Cannabis is a short-day plant: it starts flowering when the dark period is long and uninterrupted. A blackout screen lets you create that dark period at any time of year, so flowering can be planned instead of depending on the season.
Can blackout screens also prevent light emission from the greenhouse?
Yes. When assimilation lighting is on at night, a closed blackout screen keeps the light inside the greenhouse. That helps meet local light emission rules and avoids nuisance for neighbours.
Can an existing greenhouse be fitted with blackout screens?
In most cases, yes. We design blackout 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 a blackout system for your cannabis greenhouse?
See all our blackout solutions and reference projects on the ALWECO website, or ask one of our specialists for advice and a clear quotation.
Go to alweco.nl