It is sometimes necessary to temporarily remove panes from glasshouses to assist ventilation in heat waves To install in your greenhouse simply remove a pane of glass and bolt the operating parts to the glazing bars of the greenhouse. Then slide five glass blades into place - these glass blades are NOT SUPPLIED with the kit - you can use the glass pane you removed to cut into these blades to form the louvre. This Louvre Kit for your greenhouse consists of the components for a 5 bladed louvre window (excluding the glass), including the fixing bolts for fitting into an aluminium greenhouse.

External blinds: give shade and also provide the maximum cooling effect by preventing the sun's rays from passing through the glass. In periods of dull weather they can be easily drawn up again to allow maximum light on to plants. However, they are likely to be one of the more expensive options (and may interfere with vents). With larger glasshouses, one square meter of ridge ventilation for each five square metres (20%) of floor area provides the ventilating capacity to give one complete change of air within the greenhouses every two minutes. Greenhouse Megastore offers a variety of airflow solutions for growing structures of all sizes, including roof and side vents, louver windows, poly side venting, end wall venting and aluminum shutters. Our products range from heavy-duty to the most economical. Whether you need a complete greenhouse ventilation kit or a new automatic greenhouse vent opener, our greenhouse experts can help you find the right product. Unwanted air is extracted through ridge vents, allowing fresh air to enter via five or six ( model dependent) adjustable slats, to ensure draft-free ventilation of your plants. The roof vents (sometimes running the full length of the ridge and opened either manually or with automated openers)Louvre windows allow the cooler air during the summer months to enter the greenhouse at the lowest possible point. This in turn pushes the warmer air out of the open roof vent.

Leaf temperature is mainly controlled by movement of water through the plant and out through the leaf surfaces in the form of transpiration – this process has a cooling effect on the leaves. Opening vents and doors helps to release some of the heat but it is often insufficient and therefore shading is usually required from mid-spring until early autumn. N.B. If you are installing this Louvre Kit into a wooden greenhouse you will need to use woodscrews (not supplied) rather than the fixings bolts supplied. In changeable weather, vents and doors often have to be left partially open to limit sudden increases in temperature. Larger greenhouses may, at high cost, be fitted with automated ventilation and shadingOpen all doors and vents on sunny days. These can be left open at night if the temperature remains high Unfortunately, shading limits the light plants receive. As plant growth depends on light, only the minimum amount of shading should be used to keep temperatures below about 25-27ºC (77-81ºF). Otherwise, allow as much light in as possible, particularly when growing edible plants such as tomatoes. There is often no need to shade sun-loving plants such as succulents although the greenhouse is more pleasant to be in when shade is provided. There are various means of shading greenhouses and conservatories:

Increased airflow will help keep humidity levels down and avoid the conditions that certain fungal diseases - such as botrytis - enjoy, and the adjustable cooling effect of the louvre window in the summer will be welcomed by plants and gardeners alike. Glass blades for the Louvre Window Kit are not supplied, but the pane you will have to remove to fit the unit can be cut to minimise waste. Glass panes are also available from glass merchants or glaziers who will usually cut the glass into slats to fit the kit. The Louvre Window Kit replaces a 61cm (24") square pane. Keep your greenhouse cool and your plants healthy with our selection of greenhouse vent systems, auto vent openers and accessories. Good ventilation lets in the fresh air that plants need for pollination and growth. It also reduces humidity and makes the greenhouse less inviting to pests that otherwise might turn it into their new home. This Louvre Window Kit consists of the operating components for a six-bladed louvre, complete with all the fixings required for fitting to an aluminium greenhouse. A Louvre Window placed low in the sides or end of any greenhouse will help improve airflow and aid summer ventilation; both desirable traits when growing in a greenhouse. Greenhouses with toughened glass (full-length clear panes) will require one of the existing glass panes replaced with the louvre window, and then two smaller glass panes used, one for above and one for below the louvre.Fit automatic vent openers to ensure roof vents open even when you are not around. However, remember that since they work by the expansion of wax in a cylinder to open the vents, it takes time for the wax to expand. Provide plenty of alternative ventilation (i.e. doors and side vents)to prevent damaging temperatures occurring before the openers respond Greenhouses with horticultural glass (2ft x 2ft overlapping panes) will simply have one of the existing glass panes replaced with the louvre window. They can also be paired with an auto louvre window openerto turn the louvre from manually openable, to automatic opening, to cut down on having to open and close the louvre window yourself. Opening the greenhouse door is not as effective, as it allows a wall of air in rather than a stream, so the circulation is not as effective. Leaving the door open also means that your greenhouse and its contents are at risk from the neighbours' domestic pets, urban foxes and other garden animals. How to Fit a Louvre Window

Air movement is the second important factor, air movement over the leaf surfaces also has a cooling effect. Ventilation

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We offer systems for both passive and active greenhouse ventilation. Passive greenhouse vents rely on natural pressure differences to move air through the structure. A greenhouse roof vent is the most effective passive setup. Active greenhouse vents use electric fans and other equipment to force air in and out of the building. This increases airflow, especially for side vents, but requires a power source.