I need to set up a small grow light system to maintain small some desert rose plants over the winter. The larger plants go into dormancy, but I'd like to keep the small ones growing throughout the winter. They don't need to flower. And if I knew what I was doing, it would be good. I have $100 of free gift cards from Lowes, so I need to get everything there. I have a small space, 4' x 1 1/2" shelf to use.
sorry I'm a bit late on finding this. T5 lighting is the most efficient lighting you will find. By that i mean they have the highest light out put (lumens/lux) per watt. T8 and CFL place next for energy efficiency. when Supplementing natural light with artificial light there are three areas you can manipulate to achieve the growth habit you are looking for. They are light intensity measured in lumens and lux. Light spectrum measured in in Kelvin. and light duration measured in time.
Lumens, In general, rapid growth requires a high level of lumens. the specific amount needed depends on the plant and the environment it wishes to live. if your plant wants direct sun light and full sun then by all means add as much light as your wallet can handle. if it wants shade you probably don't want more than 5000 lumens. one more thing to consider. the light out put of the bulb is probably measured an inch away from it. the greater the distance your plants are from the bulb the less lumens they receive. this is why you see people running fluorescent strips two inches from their plants.
Light spectrum is much easier to figure out. Blue spectrums (6500K) promote vegetative growth. yellow spectrums (2700k) promote flowering. (i like to use a combination of both for my set up)
Time is an interesting one. plants can go for days with out light but will die if they don't get darkness. each plant has a minimal requirement for the amount of darkens it needs to receive. typically the maximum you can leave your lights on is an eighteen hour day. This would simulate the longest day of the year year round. this would cause prolific vegetative growth & potentially an insane electric bill. If you want to cause flowering duration of light also plays a roll. does your plant flower in the summer or fall? during the summer the days are long therefor long duration of light is needed. during the fall the days are not their shortest but they are working towards that point. try starting at14 hours and cut it back an hour each week until you notice flower buds.
Now i know that there is a lot of science involved in this but its fun to play with and modify once you figure out the basics. for example... i collect tropicals and succulents. i also live in zone 7 which means my garden comes in every year. when i cram them in together they take up about 2.5 sq meters of floor space. i have a large south facing window which is about this wide. this is where i built my setup. i run one 4' T5 that has an out put of 10000 initial lumens @ 6500K centered directly above the entire space and about four feet off the ground. This enables the light to hit a wide area. it also allows my coffee the "shade" it likes. I then use a 150W equivalent CFL @ 2700K hanging at the same height to add an additional 3000 lumens and the yellow spectrum. so far what i have created is 13000 lumens with mixed spectrum giving a broad base light to my entire bed. now i mentioned i have succulents and tropicals half of which want really bright light. a simple 23W CFL with a $5 clip-on fixture is the answer to that. i simply use them as spot lights about 6" from the plant that wants bright light. I run two of those. in total i am running 15000 lumens and spending around 200W. the set up cost me $50 for the T5 and about $30 for the CFLs and Cheap fixtures. I also mentioned that this was all in front of a big south facing window. there is a reason for that. my lights turn on at 6 am and off again at 9am when the sun is directly in my window. At 3pm my lights turn back on and run until 1030pm. my plants get 16.5 hours of light a day but i only pay for 10.5 hours. in all it costs about $4 a month to run and i get insane growth out of my plants. ... Did i post this in the energy efficient forum?
Hope you were able to follow all that and that it helped at least with any future set ups DGer's want to create.
Uh, T5's are not more efficient than T8's. T5 tubes are smaller and hence have less of a problem with strikeback than T8's, but the lumen production per watt is about the same. T5 also tends to lose more lumens over the lifespan of the tube -vs- T8 because of higher internal temperatures due to the small diameter. Since the reflector's are smaller you can typically cram more T5's per linear foot, and so a 8x T5 fixture is about the same size as a 4x T8. Otherwise, T8 fixtures are far more common than T5 and far more often to be found on sale.
CFL's are the least efficient fluorescent technology because of their spiral shape, and significantly worse than halide or T5/T8. That's why only linear CFL is used in commercial applications.
I used to run T8's, but now build my own LED rigs and get 120-150lumens per watt depending on LED's used. Commercial LED fixtures tend to be rip-offs.