I would like to have an indoors garden and have florescent light fixtures already installed. What type of bulbs can I replace the florescent bulbs with that will give the kind of light to make plants flourish?
What kind of plants do you want to grow? What do you mean by “light fixtures already installed” - a grow light setup, or overhead fixtures in a room (how many, in what size room), etc?
Wow, I didn’t know it would be so complex. I have a room about 12 x 12 feet with not too much natural light from a small window. The ceiling has florescent lights which now produces the light for the room. I would say two bulbs about three feet long each.
What will I grow? Indoors plants and flowers. Not sure exactly as I haven’t yet done research as what will grow, nor have I gone shopping to see what is available.
“Grow Lights”.
UV tubes are too extreme. You want something just a bit bluer than an ordinary “White Light” tube. You can still buy florescent tube grow lights, but the problem is that they don’t actually put out a great deal of light, so people are moving to LED tubes.
LED tubes are more expensive, but brighter and last longer. You can buy normal LED tubes that work as direct replacement tubes (remove the starter from fitting), but I don’t know if they are suitable as grow lights.
What I’d like to grow is cheery tomatoes, peppers, basil, cilantro, and some of the spices. Can’t get too large but the fresh stuff has the snappy flavor that makes things extra tasty.
You will need many watts of LEDs hanging 10-40 cm over the plants. I would buy the cheapest daylight (4000-6000 Kelvin) bulbs I can find. Plant lights might be a little more efficient but they might also be a lot more expensive. In general, both good fruit and good flower production require a lot of light.
OK - was just asking to get some info so more experienced gardeners can check in.
(My guess is that, unfortunately, you will not get nearly enough light to grow much of anything in that setup - you need to somewhat replicate natural outdoor light, which is much, much brighter - think bulbs hanging a foot or so over your plants.)
Leave the fluorescent ceiling lights there to light up the room, and add grow lights close 12-18 inches from your plants.
Plant leaves grow best with 3,000-4,000 lumens per square foot. A standard 60-watt bulb (or a CFL or LED equivalent) is about 800 lumens. That’s a great deal of light, but our sun is pretty big. Even just 500-1000 lumens per square foot will greatly aid your plant growth. (Sellers of grow lights will claim much more coverage for their lights; buyer beware (or be aware).)
Another consideration is room temperature. Most plants grow slower once the room temp goes over 85ºF. It can be a balancing game to get the optimal amount of light close to the plants without raising the temp too high.
Also the shade (color temperature) of the light affects this. ‘Cool’ (2500K-3000K) bluish light is best for growing plants; ‘warm’ (5000K-6500K) is best when plants start flowering. Some people have their grow lights set up with some of each, wired separately, and vary the amount/time of them to be more reddish as the plants mature.
You also need to worry about the height of the lights; close enough for seedlings won’t work when the plants reach full height. Some way of adjusting the height of the lights is helpful. Concentrating on ‘dwarf’ or mini varieties reduces this problem (but many of those don’t produce as much or as long as regular varieties).
Lumens are for humans, plants don’t care. I’ve used cheap ass Home Despot T8 four foot fluorescents, the kind with two tubes per fixture, to grow all kinds of stuff. I have a pothos plant that I bought for my grandmother in 1984, it’s still growing like gangbusters, draped all over a shed with shoots spreading probably 8-12 feet and some of the leaves are the size of dinner plates–that’s mostly growing under two T8 fixtures with a little side light from a couple of T5 8 bulb 4’ fixtures. Right next to the pothos is a huge schefflera I started from a cutting off a house plant, I’m growing it for a friend’s new office–it’s about three feet tall now. One of those T8s works fine to start seedlings up to maybe a foot high, you just mount them maybe 18" from the shelf or floor where the seedlings are.
So, basically, you don’t need much in the way of fluorescents to grow stuff, the main thing is to get the light down close to what you’re growing. Ceiling fixtures will keep plants going but they’re likely to get leggy–they’ll be much more compact with a closer light source. You want blue spectrum for vegetative growth, around the 6000 Kelvin or higher range (cool), and add in some more red spectrum bulbs if you’re trying to flower, like fruiting tomatoes or peppers. That’s around the 4000K (warm white) or lower spectrum. That’ll pretty much do the job unless you’re trying to grow cannabis–they have a lot higher PAR requirements than most houseplants of veggies.
I made a small, indoor system for growing starter plants for our garden. It uses a 4 foot, four bulb, fluorescent fixture with the following bulbs installed:
Bulb 1: Cool (2500 K - 3000 K) light
Bulb 2: Warm (5000 K - 6500 K) light
Bulb 3: Cool (2500 K - 3000 K) light
Bulb 4: Warm (5000 K - 6500 K) light
Seems to work well.
Confusing when you call ‘tubes’ ‘bulbs’…
Even more confusing that you actually mean lamps or lights - bulbs are planted in the garden to produce plants…:)
As most everybody has said, you need the lights to be much closer than ceiling to floor or table; you want the lights to be within a few inches of the plants, just far enough away to prevent the plants from overheating. You move the lights as the plants grow to keep them in close proximity.
The fluorescent tubes sold in big box stores as grow lights are usually just standard tubes with a blue coating on them; they actually provide less light usable by the plants because the blue coating blocks some of the light, so you’re better off just using standard tubes.
The new LED grow lights do provide a good balanced spectrum for plant growth. The purplish color is produced by the LEDs rather than by being filtered by blocking some of the colors like fluorescent grow lights.
If you’re planning on growing hydroponically (and I suggest you should, for much faster growth than in dirt), those AeroGarden gadgets really do work pretty well. They’re a little pricey but often available on sale and you’d be spending some bucks piecing together your own hydroponic setup anyway. An AeroGarden will get you up and producing very quickly, giving you a taste of indoor gardening while you research and think about how far you want to go with it.
Do check for LED plant lights that are on strips that are to be oriented vertically in the plant pot close to the stem. Those are things that you can find online.
The consensus here is that you will need very strong illumination for plants to grow – its not as simple as getting a balance of wavelengths. I’ll share with you my experience.
Two years ago, I tried to grow one Roma tomato plant in a large pot in my tiny windowed apartment. I knew like you d that the plant needs more wavelengths than standard lights produce. I put it where it would get the 30 min of natural sunlight it could have gotten if it grew 3 ft tall. Directly overhead was a standard fluorescent bulb (whatever lumens = 60W) and an LED blub, same lumens, a bit closer. And other room lights left on.
The plant grew, and the leaves were a healthy color, but the stem was slender, and it didn’t leaf out fully. It wouldn’t have fruited.
You need more intense light for a plant to grow and produce fruit. Wavelength isn’t the whole answer. Off topic, but a strong stem in tomatoes requires wind stimulation, or replication with physical action on the sprouting tomato. Ref: Rech, Hydroponic Food Production: A Definitive Guidebook for the Advanced Home ... - Howard M. Resh - Google Books
Not this: plant pot grow lights - Google Shopping
But instead this: How To Make Your Own Grow Lights | Popular Science
You’ll spend more on electricity, but do look into a metal halide fixture. You’ll get more vigorous growth and a much better harvest.
Don’t point a newbie at a “metal halide fixture,” because sure as eggs is eggs they’ll go off to Home Despot and get a big stupid spotlight that eats electricity like mad and does nothing aside from throw off a lot of heat.
If all you want to do is to grow some salad greens and the like, fluorescents are perfectly adequate so long as you get them down right on top of the plants. If you want something that produces fruit, like tomatoes, you’ll need something a bit more robust and that will involve an actual proper grow light and bulb, Which will need 220v electrical supply, a ballast and some means to dissipate the heat–plus you’ll need a timer too. Because you can grow stuff under fluorescents using a 24 hour photoperiod and they’ll do pretty well but you really don’t want to try that with even a smaller 400 or 600w grow light fixture. So much heat, and it will be a lot cheaper just to buy tomatoes than to pay your electric bill!
To grow fruiting veg indoors, probably the best compromise is an 8 tube, T5 fixture that is at minimum four feet long. The shorter ones just don’t put out the light you’ll need to try to cover a big tomato plant. Use half warm, half cool spectrum and you will likely get a pretty decent yield off the plant, which will probably be okay with a 24 hour light period too. Eventually the plant will just play out, get tired and die off but if you have another plant coming up you can keep producing for, effectively, forever. T5 fixtures don’t have the heat problem of a larger grow light, they’re easy on the power bill and relatively inexpensive to buy, although the replacement tubes are more spendy than a T8.
Another option is to go for a full spectrum LED fixture, like this one:
Advantage of these fixtures is low power consumption, basically no heat production, long bulb life and the only light being produced is in the spectrum the plant uses–again, lumens are for humans, plants need PAR and that’s all the LED fixtures produce. Drawback is that this fixture only covers, at best, a 3x3 area so if you want to really do some indoor gardening you’ll need several of these to make it work. They look weird but they work just fine.
You can rig up a very nice indoor salad garden using a heavy duty metal shelving unit with your fluorescent or LED fixtures mounted above each shelf. Use a fairly shallow shelf for salad greens and a taller one underneath for your fruiting plants. Three shelves will produce a lot more plant than you might think.
Oh, and if you want to grow cilantro, pinch it back constantly or it will go to seed and after that it’s useless. Pinch pinch pinch, all the time.
I kindasorta disagree, though I see your point. OP has a 12x12 room and I can picture a setup that would have him rolling in salad all year long. In the winter the waste heat would help heat his home, in the summer he could either grow outdoors or work out a plan to vent heat.
I was in a hydroponics shop once and a customer was picking up some spare bulbs for his tomatoes. The cashier laughed at “tomatoes”, leading the customer to pull out his phone and show off the pictures of his indoor jungle . . . of tomatoes and other veggies.
Good info here guys. I think I will have a very good start and I’m pretty optimistic.
tyvm 8^)
I have had considerable luck using 6 ft SHO (Super-High-Output) florescent tubes optimized for plants, multiple fixtures, hung close to the plants and raised when necessary. Maybe it wouldn’t have worked for high-class plants, but it worked pretty well for weeds.