This article will primarily address Lights, if you want a further review of the amount of electricity you can use safely refer to our article on Electricity.
Basically, you are replacing the sun! There are lots of very complicated books on what type of light an indoor gardener needs. The cannabis growing industry in particular has some extensive reading on this subject. I would venture on to their sites hoping they wouldn’t flag me as a cannabis grower but the information there was daunting. They describe how different stages of the plant, whether budding or fruiting, require different spectrums of light than the spectrum required for increasing vegetation. A lot of very sophisticated cannabis growers out there take this very seriously and move their plants from blue lights (for vegetation) to red lights (for fruiting) throughout the growing phase. And I’m sure they get better yields with that. But the plain white LED lights I have been using work just fine.
Halide lights with names like T1800 and T5300 are supposedly great but they are extremely expensive and need serious ventilation. They are really not for the hobbyist, but for the professional grower. The advice on this subject was a bit overwhelming and the lighting choices were expensive. The most expensive part of this whole endeavor, actually.
I didn’t want to deal with all that so I simply bought some relatively cheap, white, LED shop lights at home depot. And the plants grew fine. They fruited, flowered, seeded, made vegetables. The whole deal. I wasn’t getting the biggest flowers in the world, so I increased the time the lights were on, and they responded with even more growth. The other major added bonus of LED lights was they were simply not going to overrun my voltage capacity because they all use a fraction of what other lights use. So from here on out, I’m going to assume you are using LED lights. Because they are the best!
The LED companies recommend 32 watts/square foot of plants you are trying to promote flowering. So, you could calculate your available space, do the math and figure out the wattage you need. I did my system sort of backwards. I kept adding more lights, hanging more, then placing more plants into the spots, always checking my work with the light sensor and with the actually health of the plants. It’s probably better to plan it out so let me help you with that.
First, measure all the areas that need light/have plants. Add all the areas together. In my case this is the shower, the tub area, and the seedling mat area. I measured it in inches. It adds up to 5400 square inches. Divide that by 12 and then 12 again to get to square feet. That gets me to 37.5 square feet of plants that need light.
At the recommended levels of 32 watts of light/square foot that means I should have (37.5 square feet x 32 watts) 1200 watts of lights for adequate flowering and vegetable production.
Interestingly, after I added up what I actually have, I only have 915 watts and it’s all working out. So go figure. Maybe I’ll move that shop vac out and put more lights in….just don’t tell my husband.
Eventually I will tackle the subject of all the different types of lighting options and what they each can provide, because ultimately this is a super important topic and I have read extensively about it. But at this point, I’m going with what has been working. It’s ok not to worry about it too much and just get your plants some regular white light. As long as they have enough light, they’ll do ok.
I worried over the day/night cycle. I had learned that many plants would only grow or fruit or flower when triggered by the right day to night cycle. But this also didn’t seem to be the case in my little indoor oasis. Currently, my garden is set to a whopping 18 hours of lighting and just 6 hours of darkness. Make sure all of your timers are set to the same time so everything shuts off at the same time and there is actual darkness.
I also learned about the distance the light is from the plant. This one really does make a difference. The closer you get the light to the plant, the more light that plant receives. Like, exponentially. But the downside is, the less area that same light covers. So it’s really all about trying to get the plants as close to the light as they can but still getting the most out of your lights. You could buy a thousand lights and get them as close as possible but that could be prohibitively expensive. Don’t let the lights be the thing that turns you off. The LED lights that I have tend to not get warm like the fancy halide lights so I don’t really have to worry about them burning the plants, even if they’re really close, or even touching the plants. I have found that the best way to get the lights close close close is to put them on pulleys. My first try at pulleys was complicated and a total mess and confusing as to how to pull them up. I simplified it the second time around and am quite happy with the results. The lights can go up and down with the growth of the plant, and are very easy to move up and out of the way as needed for tending to the plants without bonking your head on lights constantly. The key here, is the fewer moves needed, the better. I strapped all of the lights in each section together so that with one move, they would all go up or down. If it’s not simple, you’re just going to leave them in place, let your head bonk on them and then you’ll just stop gardening because it’s such a nuisance. The system I used can be found in any hardware store.
Here is a schematic of the layout using LED shop lights zip tied to a PVC pipe with holes drilled for the zip ties. You could use a piece of wood or any other light, rigid item in place of the pvc pipe. Then I used the parachute cord and a cam jam to attach it to the ceiling in a way that allows for adjustable heights
Here they are in the room itself. The more lights you can put on one elevation system, the more convenient it will be.
Light sensor. This is probably a “must have”. They are inexpensive and they’re easy to use. Do your work with the lights up and out of the way, then put your lights back down when you’re done. You can eyeball that everything is getting some light and then use this handy little sensor to make sure that the lowest light spots aren’t too low to prevent growth. The one I’m using here also measures moisture and pH.
Overall, the topic of light is a very complicated one and there is an overwhelming amount of information dedicated to it. I will devote more time to the topic in the future to explain why the different types of light work so well for different applications. But I want to encourage you to just get growing. And I want to reassure you that your more common-place LED shop lights, CFL light bulbs and regular white light bulbs will absolutely get the job done. Just get them close.