Caring for orchids on the windowsill

Until about forty years ago, it was still controversial whether orchids were suitable as houseplants at all, as they are extremely sensitive, have very specific requirements and are not used to the climatic conditions in our home.

However, with the spread of central heating and the progress of modern plant breeding, which produced more adapted and robust orchid species, the orchid developed over time into one of the Germans’ favorite houseplants and today it is impossible to imagine our living rooms without it. However, a few things need to be taken into account to make the windowsill at home a suitable place for orchids.

The exotic flowering plants feel most at home in a terrarium, where all the growth factors are perfectly adapted to their conditions. However, the vast majority of species can also be cultivated perfectly on a windowsill. However, you should bear in mind the conditions of the room in which the orchid will be placed. Temperature, incidence of light and humidity as well as their fluctuations throughout the day and year influence which variety is suitable. As variable as orchids are in their appearance, so too are their location requirements.

Tips and tricks for the windowsill

Even if a location is not ideal for a particular orchid from the outset, with a few tricks almost any windowsill can be turned into the perfect orchid home.

Windows in hallways or stairwells are generally less suitable for orchids as they are often too draughty. Rooms heated by fireplaces are also not ideal locations because the heat distribution is more uneven here than in rooms heated by central heating. In addition, the room temperature is comparatively more difficult to control and fluctuates more between day and night and between summer and winter. In fact, it has only been so easy to keep orchids on the windowsill since the 1980s, when central heating became standard.

As the radiators in most apartments are located under the windows, window sills that are to accommodate orchids must not be too narrow.

Observe humidity depending on the room

 

Rising heating air dries out the plant and stresses it. This makes it susceptible to pests, reduces its growth, blooms less frequently and sheds dried buds before they open. In any case, the relative humidity in our living rooms and bedrooms is often too low for orchids, especially in winter. In most households, it is between forty and sixty percent.

For orchids to thrive, the values must always be at the upper end of this range. This is why orchids such as the moisture-loving Vanda are particularly well suited to bright bathroom or kitchen windows, where steam from the shower or saucepan moistens the leaves every day.

Tips for window sills in rather dry rooms

To meet the requirements of Phalaenopsis and co. in rather dry rooms, it has proven useful to spray the leaves, aerial roots and flower buds daily with water until a thin film of moisture wets the leaves.

Caution: Spraying the orchid dripping wet is counterproductive. If the water does not evaporate from the leaves within a few hours and at the latest by nightfall, mold spores can germinate and make the plant sick.

If you don’t want to think about spraying every day, choose a pot two sizes larger for the orchid, place expanded clay or a few stones on the bottom and add a little water, just enough so that the orchid substrate and roots don’t get wet. The water will gradually evaporate from the planter and increase the humidity locally.

A similar effect can be achieved with special window bowls that supply several plants with moisture at the same time, or simply by placing bowls filled with water between the orchids.

In contrast to temperature, fluctuations in relative humidity are better tolerated by orchids, as long as they do not fall below a value of fifty percent. After all, such fluctuations are commonplace in nature due to alternating rain showers and solar radiation.

What is the best orientation for orchids on windowsills?

Just like us, orchids cannot tolerate too much sunlight in spring when the sun is gaining strength. They have to get used to it slowly.

The ideal windowsill for growing orchids faces east or west so that only mild morning or evening sunlight enters.

Direct sunlight at midday on a south-facing window is too intense for the tropical plant, which only knows diffuse light from its native jungle, which hits its leaves through the canopy of the jungle trees. If you expose your orchid to the midday sun in summer, you risk sunburn. For species such as Dendrobium kingianum or Calanthe vestita, windows that never receive direct sunlight are the preferred location. Pleated blinds can be used to reduce direct sunlight if necessary.

However, it can still get too hot on such a shaded windowsill. If temperatures climb above 25 degrees, whether due to the midday sun or a heatwave, the plant must be actively cooled to avoid risking damage. It is now doubly important to spray the orchid so that the evaporative cooling protects the plant from overheating.

Alternatively, you can line the planter with sphagnum mossand sprinkle it with water to keep it constantly moist. The water evaporating from the moss acts like an air conditioner. It is best to place a few stones in the planter to ensure that watering does not cause waterlogging. Also make sure that the plants are not too close together on the windowsill, as heat build-up can only be prevented by sufficient air circulation.

What is the optimum temperature for orchids at the window?

Fortunately, the optimum temperatures for orchids are exactly the same as those we prefer in our living rooms: 18 to 24 degrees. It can cool down to 16 degrees at night, and a difference of up to five degrees between day and night temperatures is even beneficial for growth and flowering.

An unheated but sun-drenched conservatory is the perfect home for Dendrobium or lady’s slipper. They tolerate temperatures of up to 15 degrees as long as the light intensity is right. Phalaenopsis , on the other hand, does not like temperatures below twenty degrees and is more suitable as an ornamental plant for living rooms and kitchens.