I moved into my appartment mid last year. Since it has a garage in the basement, I setup some grow lights (2 T8 grow lights) and a makeshift plant tray. The lights are mounted about three feet above the ground and most of the plants are placed about 3 inches off the grown. The lights run 16 hours a day.
Most of my plants survived the winter, a few didn't.
My petunia died, part of my aloe plant died (although it's thriving right now), half my rosemary died (the side facing away from the lights, forgot to rotate pot). My oregano and basil died. My mint did fine, my hawthonia did fine, and a couple other plants I don't know the names for lived fairly well.
However, none of them really grew in the basement. I've put most of the plants outside now that it's warmed up and am slowly nursing them back to health. However, I don't want to have to do this all over next year.
I can of a few problems with my setup:
There is only two bulbs, I have a second fixture, but it's not operating at the moment. Perhaps there wasn't enough light.
The pots never seemed to dry completely. Even though when I watered them they fizzed (bubbled?) like the soil was very try, but the finger test seemed to indicate they were still moist (could I have been tricked by the cooler temps?)
The plants' "day" never varied. Was always 16 hours of light, followed by 8 hours of darkness.
The temp did not vary much. Stayed a consistent 55-60 F all winter. Now it hovers just barely above that. I'm guessing the whole years range may only be 55-65.
What can I do to improve my setup so my plants do better next time around?
I'd put the lights closer to the plants, if you get more than a few inches above the tops of the plants the light intensity drops off dramatically. Also watch your watering, at those cool temps the plants aren't going to go through water very quickly and a number of the plants you mentioned are going to be sensitive to overwatering anyway.
When I was attending Michigan State University they ran an experiment on growing roses inside. One of the things that they did was to place florescent lights vertical along the sides of the plants and with those above they had success in bringing the roses to flower. I don't know if this will work for you on the type of plants that you have but it may be worth a try, it does require more fixtures and that may be prohibitive. Also temperature has a lot to do with plant growth so your watering may have to be adjusted. Another thing that I have used when growing plants inside is I incorporated incandescent bulbs along with the florescent. This provides more of the light spectrum that helps in plant growth. The main problem with these bulbs is that they will heat and if to close to the plants they will burn.
I am using the "grow light" florescents. They display more of the red spectrum than normal bulbs. Red and Blue colors is what plants use (see: http://www.firstrays.com/Pictures/Chlorophyll.jpg "Chlorophyll Absorption Spectrum of Visible Light"). I also have a couple 1 (or 3?) Watt Cree LED bulbs that emit the correct red wavelength, but they are not in use. Incandescents give of mostly the yellow regions of the spectrum, which aren't useful to plants, however they would give off heat, which may be very much in need. Do you have a link to the experiment?
The reason I don't have the bulbs closer is that the plants range in height considerably.
I did some looking but could not find that experiment published but will continue to look into it. I think it was Dr. Will Carlson of the Horticulture dept. at MSU who was the one in charge at that time.
I did find several good published articles on the Web site for the MSU dept. or Horticulture.
Plain old fluorescent lights typically work fine for plants, and even with the grow lights you're going to have the same issue where if the lights aren't close enough to the plants they don't do much good. Can you set up a couple different lights and put taller plants under one of them and have a 2nd set of lower lights for the shorter plants? You may not be able to get things perfect if you have a big range of heights but by separating plants into a couple groups you might be able to do better than you're doing now.
But, since you have things dying, I suspect a watering issue may be the primary cause of your problems (too much water being way more likely than too little). Inadequate light will make plants grow leggy & spindly and they might not be the healthiest they could be, but they shouldn't die unless something else is going on too. All of your plants should be fine with 55-60 degree temps, but with cooler temperatures they won't go through water as quickly so if you have a heavy hand with the watering can or have soil that's too moisture retentive that makes it very easy to overwater.
I agree that your problem is too little light and probably too much water. The petunia and the aloe probably died from root rot . . . easy to kill these this way. The rosemary is a full sun plant and even though they are really hardy . . . they need lots of light. The oregano is short and far from the light source. Basil is an annual. I'm suprised the mint survived and as long as you don't over water the haworthia I'm always amazed at how they can over winter just about anywhere. Growing under lights is HARD. You'll need to look up every plants needs and try to accomidate them individually. I had an indoor orchid box. I bought a light meter to see where in the box was the best place for the different plants. It amazed me how much light and how close to the light the plants had to be. The light intensity dropped off really fast, like within 4 feet it went from full sun to full shade and I had a high intensity grow light.
I don't have a fan, hadn't thought of that. That's a really good idea.
The aloe lived, just part of it died.I cut off all the dead bits and it's got a good bit of bright green new growth now that it's warmed up a bit.
The light fixtures aren't really movable, They're the 4' lights, and they're sitting atop a two tiered wire shelf. I'm going to put the shorter plants on the top self, that should make them less than a couple inches from the light.
down here in Texas the air has enuff humidity in it that the aloe lives bare root in the places we stick it for a year- and can be replanted in warmer weather- or when you seperate the pups and dont have time to plant them immediately, good luck, and yes, lights are why I wont put plants indoors, and you think the bulbs are good because you can see with them? Oh No, they lose their effectiveness as fast as fleas find poodles. Good luck
If I bring plants inside for winter, I only give enough water to prevent the plants from dying as winter is normally the plants rest period, unless you are talking about seed propagation. I have to always check them as keeping them alive is not easy in this different type of environment.
I never use lights and to be honest, even in our very dark (little Light) winter days, there is still enough light to prevent the plants dying off. I would imagine your petunia had lived it's life as they are normally summer season plants and unless fed, dead headed and given good light, I would not expect these to continue to flourish over the winter months and to try grow them for the following summer I would be thinking of cuttings rather than keep the original plants.
Don't be put off trying again as trying to grow plants in un-natural conditions takes a bit of practice and everyone will have different conditions like light, airflow, temp etc, so just keep trying to alter the conditions till you hit the right way for you but all plants require the basic treatment at different times of the year. Good luck for the next time. WeeNel.