As optimal as a sun-drenched greenhouse is good for the seedlings and young plants during the frosty winter and spring months, the dry and hot summer time with its extreme temperatures can be all the more problematic for the plants housed under the roof. Tropical heat makes things difficult for the plants, so that some technical precautions are required in the greenhouse even at temperatures above 30° C. Why it is like that?

Shade netting is one way to create shade in the greenhouse

When too much sun is bad

The optimal comfort and growth temperatures for greenhouse plants are between 20 and 30° C, depending on the genus or species. If windows and doors are closed, extreme values of over 50° C are reached relatively quickly in summer, which in turn means that the vital Gradually decompose protein compounds and enzymes of the plants. In addition, there is the so-called glass house effect, which from a physical point of view ensures that short-wave sunlight is converted into long-wave thermal radiation in the interior and is additionally reflected several times by the glass surfaces.

What happens in the plant when it is hot?

Under normal temperature conditions, plants use evaporative cooling that occurs automatically on their surface. The higher and faster the temperature inside the glass house or foil tent rises, the more water has to be broken down inside the plant in order to keep the “normal temperature” constant. However, this form of conversion has its physical limits, so that significant leaf changes (sometimes even with visible damage) must be expected in the medium term in the range between 30 and 33°C. Usually it only takes a few days before the first long, weak shoots become visible, which can even die off shortly afterwards.

How does a climate-friendly greenhouse understand itself?

The best and most important thing you can do to your plants in the greenhouse is therefore a good climate. Some prerequisites for this can already be created with the purchase of a greenhouse equipped with as many ventilation openings as possible. In cheap specimens made of clear glass, where savings have been made on windows and doors, there is usually a risk of rapid sunburn. It is just as important that these openings are at different heights, because for a healthy climate there must also be well-functioning and flowing air circulation, which otherwise should be retrofitted with an additional fan.

From chalk and shading nets to reeds and cooling interior blinds

As is well known, many roads lead to Rome and garden lovers have at least as many opportunities to retrofit their greenhouse in a plant-friendly and climatically optimal manner. A particularly inexpensive, fast and alternative shading that can be implemented with little effort is to paint the entire outer shell with a mixture of water and whitewash. And it goes like this:

White chalk & water - the (almost) free greenhouse shade

By far the easiest, as well as inexpensive, way to retrofit your greenhouse with exterior shading is to paint, roll or spray with whitewash, for which you need to obtain the following materials for a medium-sized house:

  • 25 kg whitewash
  • 30 liters of water
  • Brush, paint roller, painter's brush, paint bucket and stirring stick

Before applying the not too thickly mixed liquid, the outside of the glass panes should at least have been thoroughly cleaned. Whether all sides have to be painted depends essentially on where the afternoon sun is most intense for a tropical climate inside the house. Later, nature takes care of washing off the paint almost independently, because with every rain shower the paint will have almost completely dissolved by autumn.

tips

If necessary, remove any remaining residue from the glass surface with a special or household cleaner before the start of the next growing season. It is better not to use this method on houses covered with plastic (double-wall sheets), since this material is very sensitive to scratches, which are almost inevitable when the paint is later removed.

Shading nets: high effect over several years of use

Shading fabric is available by the meter in all sorts of sizes and thicknesses from specialist gardening stores and will help you reduce solar radiation by 50 to 60 percent. With an average weight of 60 to 100 g/m2, this dark green to black colored material is stabilized against UV rays, opaque, growth-promoting and even hail-resistant to a certain extent. The most common standard widths of the nets are:

  • 1.00 m
  • 1.50 m
  • 2.00 m
  • 3.00m and
  • 6.00 m

The average prices at the time of going to press for this article are between 1.45 and 1.90 euros per square meter with a material thickness of 60 g/m2. Due to the high temperature and rot resistance of the fabric, service lives of up to five years are not unusual.

tips

It is essential to ensure that the shading nets are firmly seated, which are held in place in the ground or on the greenhouse walls with the help of special clips (with an integrated eyelet), ground anchors or ground pegs or with a suitable net adhesive tape.

Shade dispenser made of reeds - natural and environmentally friendly

Just as effective as the shading nets, which are mostly made of synthetic materials, are natural reed mats as perennial sun protection for greenhouses (77.12€) of all sizes. When installing the membranes, make sure that all existing windows and doors in your greenhouse can still be opened easily and fully afterwards to ensure unhindered air circulation. Unless you come across particularly inexpensive reed mats in special offers outside of the gardening season, you have to expect prices between a good 3.00 and just over 5.00 euros per square meter when buying from most common online retailers.

Interior shading with roller blinds - a touch of luxury

The shading nets and reed mats just mentioned are of course just as perfect for indoor installation as for the outer shell of greenhouses. The roller blinds are much more comfortable in terms of individual temperature control. Depending on the current intensity of the sunlight, the completely pre-assembled sets can be continuously adjusted, which ideally leads to relatively constant temperature conditions throughout the interior of your greenhouse.

Of course, this luxury has its price: We discovered a 620 mm wide, 195 cm long shading roller blind with all mounting accessories in black and a shade value of 55 percent online for EUR 129.00 plus shipping. For perfectionists, there are roller blinds and awnings as interior shading with motor drives, which are automatically controlled via several temperature sensors and, integrated into modern SmartHome systems, can also be controlled when you are away from the property.

Category:

Garden design