Table of contents:

What Interferes With The Normal Development Of Seedlings And Indoor Plants On Window Sills With Double-glazed Windows
What Interferes With The Normal Development Of Seedlings And Indoor Plants On Window Sills With Double-glazed Windows

Video: What Interferes With The Normal Development Of Seedlings And Indoor Plants On Window Sills With Double-glazed Windows

Video: What Interferes With The Normal Development Of Seedlings And Indoor Plants On Window Sills With Double-glazed Windows
Video: How to choose plants for a windowsill | Mr Plant Geek 2023, March
Kitchen garden on the windowsill
Kitchen garden on the windowsill

After installing double-glazed windows, many gardeners I know began to complain that seedlings and indoor flowers began to grow poorly in them. I wanted to find the reason for this phenomenon. Having studied the information on the Internet, here are the conclusions I came to.

I will only write about those characteristics of a glass unit that affect plants. First, I found out about the structure of a glass unit and its main advantages.

A glass unit is a glass-air sandwich that provides modern windows with excellent heat-shielding and sound-proof properties. The outer glass is covered from the inside with a heat-saving, usually silver coating, invisible to the human eye. As a result of this protective layer, windows significantly reduce the penetration of solar radiation and reflect ultraviolet rays (that is, ultraviolet rays do not penetrate the room at all). This is done so that in summer, when it is hot and sunny outside, thermal energy (sunlight) is reflected from the glass, this protects the room from overheating, and furniture and wallpaper from burning out.

In addition to this protective layer, many consumers order glass unit manufacturers to install self-cleaning glasses with a special low-emission coating based on titanium oxide, which ensures self-cleaning of the outer glass from organic contaminants. And this is another coating that additionally blocks sunlight up to 7%.

In addition to these coatings, ultraviolet rays are also reflected by argon - an inert gas, which is most often used to fill the inside of a glass unit (the space between the glasses). This gas only allows 66% of visible light to pass through. Argon, as the cheapest gas for filling double-glazed windows, over the years (after 8-10 years) gradually evaporates through the emerging pores or microcracks, but this is not harmful for people and plants, as experts say. And for plants, on the contrary, in the opinion of biologists, it is useful, since it favors their growth.

Now let's dwell a little on the sun's rays in order to understand that plants on windows with double-glazed windows are receiving less. Sunlight (solar radiation) is the only energy source available to green plants, thanks to which, as well as water and carbon dioxide, the process of photosynthesis takes place. Solar radiation is a flux of radiation, which is electromagnetic oscillations with different wavelengths. The optical part of the solar spectrum consists of rays with different wavelengths:

  • ultraviolet (UV) with a wavelength of 290-400 nm (nanometer);
  • visible rays with a wavelength of 400-760 nm;
  • infrared rays with a wavelength of 760-2800 nm.

About 30% of solar radiation does not reach the earth's surface. Near the Earth's surface, the ultraviolet part of the solar spectrum is 1%, the visible part is 40% and the infrared part is 59%.

Of the entire spectrum, photosynthetic active (380-710 nm) and physiologically active (300-800 nm) radiation are important for plant life.

Ultra-violet rays

Ultraviolet rays with a wavelength of 315-380 nm delay the "stretching" of plants and stimulate the synthesis of some vitamins, and ultraviolet rays with a wavelength of 280-315 nm increase the cold resistance of plants. UV rays help to stop the spread of harmful microbes and fungi, purify polluted air. Summing up the above, we can say that UV rays affect the growth (plants are larger), flowering (it comes earlier), fruiting (larger fruits) and productivity (more flower buds are laid) of plants. Unfortunately, these rays are completely reflected by the glass units. Perhaps these rays still somehow affect the growth of plants, due to which the seedlings die or grow frail.

Kitchen garden on the windowsill
Kitchen garden on the windowsill

Visible rays

Spectral ranges with certain physiological characteristics are identified within these boundaries.

But the main suppliers of energy for photosynthesis from this spectrum are (they are most important) red (720-600 nm) and orange (620-595 nm) rays. This part of the spectrum is absorbed by chloroplast pigments and thus is crucial in plant life. Green plants need visible light for the formation of chlorophyll, the formation of the structure of chloroplasts; it regulates the work of the stomatal apparatus, influences gas exchange and transpiration, stimulates the biosynthesis of proteins and nucleic acids, increases the activity of a number of light-sensitive enzymes. This light also affects cell division and elongation, growth processes and plant development, determines the timing of flowering and fruiting, and has a form-building effect. In general, the red spectrum accelerates plant development, enhancing growth processes. And also there is an increase in productivity.

When the seedlings are illuminated with a red spectrum of lamps, the flowering of long-day plants (lettuce, radish, spinach) accelerates and the flowering of short-day plants (cucumber, beans, pepper, eggplant, some varieties of tomatoes) is delayed. Therefore, lamps with a red spectrum cannot be used for growing seedlings of these crops.

Visible rays in the range of 320-400 nm in small doses have a powerful bactericidal effect.

Blue (400-500 nm) rays in adult plants regulate the width of the stomata of leaves, control the movement of leaves behind the sun, and inhibit the growth of stems (they do not stretch). They stimulate the formation of proteins and regulate the rate of plant development: there is a change in the rate of development of plants in favor of reduced growth (thanks to this, the stem becomes stronger, and the leaves - larger) and the fastest onset of fruiting. Plants of a short day begin to bloom faster, and, therefore, bear fruit.

Yellow (595-565 nm) and green (565-490 nm) rays of the visible spectrum do not play a special role in plant life.

Plants receive 34% less visible rays on windows with double-glazed windows.

Infrared rays suppress the development of microflora. They also affect the timing of the ripening of the crop. If you want to get an early harvest, then you should increase the level of infrared radiation. If the growing season needs to be lengthened in order to obtain a harvest for a longer time, then the fraction of the infrared part of the spectrum must be reduced.

Now back again to the silver coating of the glass units. Their purpose also lies in the fact that in winter heat from the room, having passed inside the glass unit, is reflected from the silver coating of the glass and goes back to the apartment, which significantly reduces heating costs. In other words, the coating leaves heat where there is more. During the heating season, the tightness of modern windows, on the one hand, ensures the absence of drafts, which is good for the plants on the windowsills, but, on the other hand, there are problems with air exchange. These windows are characterized by low air permeability - they cut off a significant portion of the supply air: there is no inflow, no exhaust. Moisture is not removed during the warm period of the year, it is absorbed by walls, furniture, and during the heating period the air in the apartment is too dry - below 30% (like in the desert),while the most comfortable air humidity for humans and plants is 50-55% at a temperature of + 20 … + 21 ° C. The leaves of plants suffer from dry air very much - they dry completely or the edge of the leaf dries and turns brown.

Another problem arises in apartments with gas stoves and "sealed" sealed windows. When the gas stove is operating with closed windows, there is no air flow, and oxygen is needed for gas combustion. Consequently, oxygen burns out - it's hard for a person to breathe. But plants also need oxygen in small quantities for respiration.

When the windows with double-glazed windows are closed, the air is even more polluted than in a similar apartment with old wooden frames. Pollutants are: a) chemical (construction and finishing materials, household chemicals, furniture, gas stoves); b) biological (spores of microscopic fungi, mold and dust mites; c) EMF (electromagnetic fields): electrical appliances, electrical wiring … These pollutants are not visible to humans, but they have a huge and constant effect on him. So in an apartment with polluted air, not only people, but also plants are not comfortable.

Well, and the last reason for the poor growth of seedlings. In winter, it is very hot in an apartment with double-glazed windows, and therefore you often have to open the windows for micro-ventilation. Cold air from the street, passing through the cracks of the double-glazed window, directly enters the plants, since it does not open like an ordinary window or window, but spreads to the sides. In the process, the plants quickly cool down and die.

In my opinion, the main reason for the death or poor growth of seedlings and indoor flowers growing on window sills, where the windows are with double-glazed windows, is excessive dryness and stagnation of air during the heating season and the flow of cold air from a window open for ventilation. Protective films have almost no significant effect on plants. But ultraviolet rays, which do not pass to plants, cannot have their positive effect, which was discussed above, on plant growth.

Double-glazed windows were invented in the USA, later they came to Europe (where seedlings are not grown) and then only to Russia. Unfortunately, in our country and in other countries, detailed studies have not been carried out on the effect of double-glazed windows on plants. Therefore, our scientists have something to do. I think their research will be important for us - gardeners. I do not blame the manufacturers of double-glazed windows for the bad effect of modern windows on plants - these windows perform their task of insulating the room, protecting it from noise and dust - I just tried to explain to gardeners why their seedlings grow poorly. I hope that those gardeners who grow seedlings on windowsills with double-glazed windows will share with us their observations of how their seedlings grow, and how they take care of it, and will tell about it in the magazine.

Olga Rubtsova, gardener,

candidate of geographical sciences

Vsevolozhsky district of the

Leningrad region

Photo by the author

Popular by topic