Hours/Day

We need someone who can tell us really about how much vegetation is needed per person/day and thus area to be lighted, and how bright, so we can come up with a realistic target.

Offered by Ron.

True, there are some plants that do better with more or less, but overall, 10 hours is just fine. Another thing, plants are very adaptable. They will adjust to whatever light conditions are available. This may result in reduced yields, reduced foliage, etc. We have some time left to experiment with different periods of light, but not much. For the most of us, planning on a 10 hour rotation should be sufficient.

Offered by Roger.

For most plants, 16 hours a day is the time needed to run light. Several plants need darkness for a period of time as well. The only way to do this would be to have enclosed areas that don't allow the light generated to escape from the 3/4 area you suggest. Then you have significant ventilation issues which are very important to plant growth. Rolling the lights along for increased productivity is definitely something that should be planned in your indoor plant development. There are also plants that only require 12 hours of sunlight (but this reduces your yield). There is no free lunch here. I would suggest three rooms with two sets of lights. That way you get the 16-hour days that maximize plant growth as we know it today, which is really all we can prepare for.

Offered by John.

I recommend decreasing the coverage area by 12/16 or 3/4. The plants will now get the same amount of light in 12 hr instead of 16 hr. This will allow one to run for 12 hr and shut off or shift the lights to another room that was dark for 12 hr. One then generates electricity at a constant rate for 24 hr/day. Thus, 1.5 more growth for any given generator size. If costly LED arrays are used the same unit each 12 hr could be shifted on overhead rollers between two adjacent rooms. Some innovation would be needed.

What I am thinking of is two big open rooms with light fixtures spaced on one big grid. One light area (node on the grid) would bleed off into the next light area (next node on the grid). The spacing would be appropriate for maximum growth for the planned time the lights were on. The proper spacing you would need to come up with from your experience. The lights would then be shifted from one room to the next by way of overhead rails with pulleys assisting the motion. Would take some thought to make this simple. Around the edges of this grid where the light tapers off - plant items that will still grow with low light.

If I remember correctly the algae Chlorella only likes to be in the sun for about one minute. Then it needs darkness for about a minute. This is why it is constantly stirred. There could be some other plants that like it just fine with 5 hr of light and 5 hr of darkness. Once we are no longer using the sun for light, there is nothing magical about 24 hr. I will bet a lot of the plants that we find on this planet were not native to this planet. I suspect many came from other worlds. These might work best with a different cycle of light and dark. One could say even if this were true, by now, they have been here for so long that they surely would have adapted to the 24 hr day. This is a valid point and should be our starting point for many.

I would like to see a study on this for I will bet one can get more volume of growth for many plants if one shortens down to say 10 hr light and 10 hr dark time. This could be done over a gradient of a few generations of plants getting shorter each time. I will bet someone has done a study on this. In some cases it may turn out 16 hr of light and 16 hr of dark is optimum. Or say 16 hr of light and 5 hr of dark. Then our task is to find something that likes 5 hr of light and 16 hr of dark to grow in the other room. You get the idea many things are possible until we find the optimum solution.

Offered by Mike.