1. Firstly, why is it important to install a curtain system in my greenhouse operation?

The main reason to install any curtain system is to control the environment and your growing efficiency. This applies to both light level and quality, and the growing conditions due to consistency of air temperature, humidity and movement. Curtain systems will provide savings in both the heating and cooling costs. In the summer, curtains reflect the heat away from the growing environment, and in the winter, they reflect the energy inward. Curtains also allow for an added air buffer layer between the growing environment and the exterior shell of the greenhouse. This limits the convective airflow created by the air-cooling against the exterior shell, resulting in even temperatures throughout the crop.

2. Why are some growers installing both blackout and shade curtain systems?

First of all, the blackout systems are required for length of day control to bring the plants to flower on schedule regardless of the external daylight hours. The cannabis plant is sensitive to light and requires 12 hours of complete darkness per day.

Shade fabrics will control the amount and quality of light entering the greenhouse with some shading fabrics specifically designed to diffuse the light. Diffused light allows for deep light penetration into the plant canopy, allowing the leaves to utilize more of the light, creating stronger plants and more consistent growth.

3. Why is it important for curtain systems to close completely?

Specifically for the cannabis plant, the day length control is essential to bring the plant to flower on schedule, without uncontrolled vegetative growth or developing hermaphrodite plants caused by light leaks.

Greenhouses always create a “chimney effect” when warm air naturally rises and cooler air falls. All small openings add up to a large amount of air movement between the growing environment and the buffer zone above. A system must be closed tightly at each leading-edge closure, along all perimeter walls and around posts or mechanical perforations. If the system leaks, efficiency will drop dramatically.

4. Can you explain the difference between sliding and suspended curtain systems?

Sliding systems move the fabric on nylon wires with top wires above keeping the bundle small and flat.

Suspended systems hang the curtain from the wires with hooks that create a pleated bundle when opened. By suspending the fabric, it is not subject to abrasion on the wires caused by wind or daily operation. In quality suspended systems, your supplier will sew a loop tape aligned with each slide wire, into which the hooks are installed. This prevents tearing holes in the fabric at the hooks.

5. Can blackout curtain systems be installed in existing greenhouses?

In most cases, yes. Most light deprivation systems are installed as sliding systems. These can be installed in as little as 6 to 8 inches of travel space height in almost any profile of greenhouse. Careful design is required to ensure that the curtain will not catch on or be impeded by any structural or mechanical components, and to ensure that the curtains close tightly.