How to Grow
The Venus Flytrap

The Venus Flytrap Care Guide at FlytrapRanch.com

Light

Venus Flytraps and Light

Venus Flytraps are not shade loving plants. Although they will grow as well as they can manage in shady or indoor conditions, they will likely be weak and spindly and prone to rot if their soil is kept too wet, and they will never look their best or most colorful.

During Spring to early Summer, and late Summer through Fall, or any time the air is cool, Venus Flytraps love and grow best in full sunlight. However, during the middle part of their growing season, when summer air is the hottest and the sunlight most intense, Venus Flytraps can appreciate a little shade or diminished light in order to prevent overheating. Bright or dappled shade can help prevent leaf scalding when the sun is very intense on particularly hot days. In addition, plants growing in pots are subject to much greater heat buildup in their soil than plants that grow directly in the earth, both because of the direct sunlight that strikes the sides of the growing container, and the fact that there is relatively little soil around the plants' roots (compared to plants growing directly in the earth rather than in containers) to buffer and moderate the temperature and slow the fluctuations in temperature that occurs at different times of day or in changing weather. The soil of plants in containers can become so hot, so quickly, that in full sun on hot days the roots can literally bake, killing the plant if not protected.

Aside from the warning above about overheating, Venus Flytraps generally grow best with a lot of very bright light, either natural sunlight or artificial light. In indoor conditions, Venus Flytraps can be grown on a sunny east, south or west facing window, or under electric lights.

The two primary sources of artificial light appropriate for Venus Flytraps are fluorescent bulbs and LED (light emitting diode) arrays. Fluorescent bulbs that are manufactured specifically for growing plants produce a light spectrum that includes the major frequencies absorbed by plants to produce food for themselves by means of photosynthesis. High-intensity fluorescent bulbs (usually labeled "HO" for high-output) are recommended and are commonly available in 2-foot and 4-foot lengths. A single compact-fluorescent bulb is usually not sufficient for growing a Venus Flytrap unless it has a reflector to concentrate the light and is positioned very close to the top of the plant, but at that close distance it also presents the possibility of burning the plant with too much heat. High intensity fluorescent bulbs (T5 HO fluorescent tubes, 5/8 inch in diameter) placed 6-9 inches above a group of plants often works well.

T5 HO fluorescent bulbs and fixture
T5 HO (5/8-inch diameter, high-output) fluorescent bulbs and fixture

LED growlights are becoming common and work well, but include a few problems. LED-array growlights are usually much more expensive than fluorescent lights, and LED arrays often must be cooled with heatsinks and fans. If the fan stops working, the LEDs can overheat and burn out fairly quickly (within hours or days). Although most LED growlight manufacturers use arrays of 1-watt or 3-watt individual LEDs, those wattages can produce so much of particular frequencies of light that the growlights must be placed fairly far above the top of the plants (16-24 inches) in order to avoid being too intense. High intensity of light can stunt (diminish) the growth of Venus Flytraps and other plants rather than encourage growth.

Although LED growlights are usually designed to produce only the specific frequencies used by plants to photosynthesize (mostly in the red and blue frequencies, including far-red (infrared) and far-blue (ultraviolet)), they don't look nearly as bright to humans because they don't produce the middle part of the light spectrum (yellow and green), and therefore a person might feel that the LED lights are rather dim, or much dimmer than fluorescent lights, when in fact from the plants' perspective the LED lights might be much more intense than the broader spectrum produced by fluorescent lights.

LED grow light
An LED (light-emitting diode) growlight

Regardless of whether the light is natural or artificial, Venus Flytraps like plenty of light and fairly long spans of hours with light during their active growing season, from mid-Spring to mid-Fall. During their yearly winter or cool-period dormancy they are accustomed to less light and can rest comfortably in bright semi-shade (they still need light for photosynthesis) and with shorter photoperiods (the number of hours of light) of less than the 10-14 hours or more that Venus Flytraps prefer during their active growing season.

Stephen Doonan, FlytrapRanch.com