Shading a greenhouse is essential to its primary function, which is to offer the perfect growing environment for plants. To avoid dehydrating and stressing greenhouse plants or scorching them with too much direct sunlight, a number of inexpensive-to-sophisticated shading methods can be used. Painting on whitewash or a specially designed mixture of powder and water is effective and inexpensive. Fabric or reed screening is a more permanent solution. Adjustable blinds and automatic blinds are more costly but offer effective, easy greenhouse shading.
Painting the glass with whitewash is the least expensive way to provide shade in the greenhouse. The whitewash allows in sufficient light but diffuses it to keep plants from burning. A number of companies manufacture a powder for this purpose; mixed with water, it can be sprayed on and might spread more easily. Drawbacks of this less costly approach include the tendency for it to wash away and the time and effort that it takes to apply. In winter, this type of glass covering must be washed off to allow sufficient winter light into the greenhouse.
Although purchasing reed screening or making or buying fabric screening is more expensive at the outset, over time, it will prove to be more convenient. This type of greenhouse shading should be draped over the outside of the greenhouse across the glass that is nearest to the Earth's equator. Sturdy grommet clips should be used to hold the material to place.
Slatted blinds can be used to provide greenhouse shading by unrolling them when the temperature inside the greenhouse has gone too high. This is a good intermediate-priced option for those who are close to the greenhouse throughout the day. The glass that is nearest to the equator should be fitted with blinds both inside and outside the greenhouse in order to provide varying degrees of greenhouse shading options.
Automatic exterior greenhouse shading blinds represent the ultimate in terms of ease and efficiency. By installing the blinds on the outside of the glass, the sun's rays have no opportunity to reach the glass unless conditions are right. Light sensors control the blinds, opening them when sunlight is available and closing them when temperatures are too high. This is the best choice for commercial greenhouses or for serious hobbyists who have plenty of cash.
There are other tips that one should keep in mind when planning the best greenhouse shading. Installing shading to the outside of the greenhouse improves cooling by approximately 40 percent. Shading installed on the inside, although it is an effective method to avoid sun scorch, can dehydrate plants. To avoid this, reflective materials that are specially designed for interior use should be used. If possible, one should purchase materials that have ultraviolet (UV) protection and a relatively long life.