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Sunlight, Temperature And Humidity

Mother in law’s tongue or snake plants are attractive houseplants with gorgeous leaves. You can grow them indoors as well as outdoors. Although these sturdy Sansevieria can withstand a broad range of atmospheric situations, they cannot thrive in all conditions. Let’s learn what are the optimal conditions of light, temperature and humidity for snake plants, and how you can make a perfect environment for their growth.

Growing Conditions For Plants

Many plants that are native to one environment don’t usually survive in dissimilar environments. For instance, plants adapted to shade cannot tolerate the bright sunlight. Plants native to swampy lands will die if they don’t get enough water. Different species require varied amounts of water, types of nutrients, sunlight as well as degrees of warmth. And the range of tolerance is wide for some species, but narrow for others.

Luckily, the mother in law’s tongue is a pretty hardy species. Being originated from an arid atmosphere in Africa, they have evolved to be much tolerant. These plants can easily sustain even on low light, less water, average quality soil and no fertilizers. At the same time, snake plants survive only when the conditions are within a range. And, they can actively thrive and bloom in most ideal conditions.

How Much Light Do Snake Plants Need?

Light is the energy source for plants. All snake plants like bright light with a few hours of direct sun. However, they don’t need sunlight particularly. Any source of light including indirect sunlight, house lamps, LED lights work great. In a study for analyzing effects of changing LED light conditions on Sansevieria Trifasciata, scientists tested many different light conditions. The optimum illumination range was found to be 21446 – 26803 Lux. Furthermore, the strongest photosynthesis appears to happen at around 26803 Lux of illumination. Light intensities for Sansevieria in greenhouses should be between 1000 and 6000 foot-candles.

The proven ideal light intensity for snake plants is 26800 Lux or 2490 foot-candles.

But what does that mean in common terms?

Normally 32,000 – 120,000 lux is the typical range of illumination that the Sun provides during midday. The exact value depends on time of year, place, day-length and other atmospheric conditions.

Here’s a chart of different light intensities in various conditions

120000 luxBrightest sunlight
111000 luxBright sunlight
20000 luxShade illuminated by entire clear blue sky on midday
1000 – 2000 luxTypical overcast day on midday

A shaded area illuminated by afternoon sun in a clear blue sky is perfect for snake plants.

Sun Or Shade?

As you can see from the chart, direct bright sunlight can be too harsh for Sansevieria, especially if you live in a tropical region. While they can withstand full sun as well as low light, indirect sunlight is ideal for a snake plant. Of course the weather conditions are not perfect year-around. So depending on the climate, you can keep the snake plants in the window during summers. In this way, the plants can get a few hours of direct sun. And, in winters keep them inside in a well-lit room.

Outdoor snake plants are also generally safe. Cloudy, rainy days and winters in regions that are far from equator significantly reduce the amount of available sunlight. The shade cast by buildings and nearby plants can also help to reduce the direct bright sunlight.

What Happens If The Plant Gets Less Light?

In weak light conditions, your Sansevieria might grow a little bit slower than normal. Heavily shaded areas don’t allow sufficient light to pass, and plant leaves start to show signs of damage. Leaves of plants can grow slowly, become weak, and even change color. Typically, leaves of the snake plants develop white spots or turn completely white when they don’t get enough sunlight. The leaves can also lose their typical cross-banding pattern. If the snake plants are placed in deep shade for a long time, eventually they start dying.

What Happens If Snake Plants Get Too Much Light?

Although Sansevieria are tropical plants, more sunlight doesn’t mean it’s better. Even though plants can adjust to changes in light, photosynthesis can reach its saturation limit. Soil can easily lose moisture and dry out in direct sunlight. So, plants kept in sunny windows or outdoors may need more water than indoor plants.
If the sun is too intense, snake plants may get extremely dehydrated. Their leaves can start drooping or form cracks. Another sign of dehydration is brownish yellow tips on the leaves. Over time, it can develop brown edges along the leaves.

Ideal Temperature For Snake Plants

Plants grow best within an optimum range of temperatures; and the range can be wide or narrow depending on the species. Optimum temperatures allow the plants to carry out life-sustaining chemical processes. Snake plants are quite tough in terms of enduring a wide range of temperatures. They can survive winters as cold as 45°F (7°C) provided that the soil is dry. Damp soil during cold winter months is dangerous for these plants. On the other extreme, a snake plant can get through hot summers with temperatures up to 104°F (40°C).

Good growth of Sansevieria plants is observed at temperatures between 70 to 90°F (21 to 32°C). This temperature range promotes healthy growth and can easily be maintained in homes as well as in most greenhouses. Achieving the temperature may require minimal heating through the winter season. However, it is not customary to attempt cold protection of field-grown Sansevieria.

Research has shown that plant nutrition hugely influences the sensitivity of snake plants to cool temperatures. Excess application of Nitrogen markedly increases the level of chilling injury.

How To Protect Plants In Extreme Weather?

Small indoor plants are generally well protected from extreme temperatures. However for outdoor plants, there are few ways to keep them safe.

  • A thick layer of mulch can help insulate the plant’s roots from both heat and cold.
  • Sun shades over the outdoor gardens are beneficial to reduce sunlight.
  • Lightweight floating row covers can cover your plants without touching them.
  • Covering with sheets or blankets helps to keep warmth in and avoid frost during cold winter nights.
1024px Sansevieria bacularis

Relative Humidity

Relative humidity is a way of describing how much humidity is present in the air, compared to the maximum possible humidity. Relative humidity depends on temperature as well as atmospheric pressure. The ideal relative humidity for health and comfort is about 40–50% in closed spaces. This percentage is great for both humans and plants. During winter months, the relative humidity may have to be lower than 40% to avoid condensation on the windows.

There is no information available about the exact values for ideal relative humidity for snake plants. However, all the varieties of Sansevieria seem to prefer dry air with low humidity. In a study about growth of Sansevieria Trifasciata, researchers maintained the relative humidity at ~44%–45%. That means if the humidity in a room is comfortable for you, it’s probably good for your plants as well.

Snake plants, in particular, can handle much lower humidity than 40%. They don’t require any extra humidity even in dry winters. So, be sure to keep the leaves dry in all seasons. Do not water the snake plants frequently in winters. And definitely don’t mist them.

References and Images:

  • R.W. Henley, A.R. Chase and L.S. Osborne. Sansevieria Production Guide. CFREC-A Foliage Plant Note RH-91-30
  • Tian, Meng, Wang et. Research on the Effect of Electrical Signals on Growth of Sansevieria under Light-Emitting Diode (LED) Lighting Environment. 2015
  • Sansevieria trifasciata ‘Bantel’s Sensation’: Photo by Mokkie / CC BY-SA
  • Sansevieria bacularis: Photo by Mokkie / CC BY-SA