Bihrmann's   CAUDICIFORMS   

 Water   Watering   Nutrition  pH   Light   Ventilation  Temp.   Soil   Pots   Pruning   Rest

Most plants are quite tolerant to the amount of light they thrive under. However, they might shift form or get discolorations, if the light is wrong.
Plants have a growing hormone that is destroyed by light. That is why the underside of a branch stretch, and the plant face the light. If given too little light, the entire plant stretches towards the light.
If you want your plants nice and fat, make sure they have plenty of light. Ventilation is another factor for that. And remember to adjust your Watering.
Given too much direct sun, some plants get too hot and some of the many chemical functions in the leaves fails. Further more, it can dry-out the leaves and the plant looses them.
The leaves are grown to a specific range of light, and if that changes drastically, the plant might choose to loose the old ones, and grow new for this light intensity.

The intensity; it is so hard to judge the with your eye, as they are so good at adjusting. In the open, around equator, the intensity can reach 2000-2200 E/M2/s (110-120 K Lux), but the plants don't use that much at all. I think most of our plants will grow nicely with 150-300 E/M2/s. In winter, I can measure 1100 E/M2/s outside the window in the sun, where the plants in my windowsill only receive 750 E/M2/s in the direct sun, right behind the glass windows, and 13 E/M2/s a meter inside the room, in the shadow.

Measuring light can be done in several ways. Common for them is: It is rather expensive. I use E/M2/s (=KW/M2/gr), which is the number of photons that hit the surface. Other meters use Lux or Candela. The relation is a bit tricky, as Lux changes with the colour of the light. However, you can buy a Lux-meter for around 70, and that is a good tool.

The colour is another factor. Where the sun have a a wide range, light-tubes, bulbs and LED light have a combination, fooling us to think "white". The plants mainly use two specific ranges of blue and red, and you can buy light-sources with these colours. But they are more expensive, and personally, I hate that colour! Using the average white might cost you a bit more electricity, but the tubes/LED is so more inexpensive, and I can only measure small differences in growth.
Some plants are controlled by the colour of light. At spring and autumn, the sun passes through way more atmosphere, and the red light dominates. And the intensity changes along with the amount of hours.

The type of light source is important. If you live in an area with sufficient natural light, it is great, but some need to add artificial light. I have used all kinds of sodium-lamps, bulbs, tubes and recently; LED, which is SO great. You don't spend electricity on heat, everything become light. Further more, you can set the light right down on the plants, and save a lot that way.

How much light a specific plant need, is had to say. At first, I thought i.e. cacti from Mexico would get the full blast. But it turns out, the young plants are only found under the bushes, not in the open.
I thought South Africa plants like Dioscorea hemicrypta would get a lot of sun, but they are only found on the back-side of the steep hills, never seeing the sun.

During the winter, many of us have way too little natural light to have our plants grow. It might be necessary to force them into dormancy. That might solve another problem as well: Temperature.

 Water   Watering  Nutrition   pH   Light   Ventilation  Temp.   Soil   Pots   Pruning   Rest