I have a small balcony that doesn’t get much (any) direct sunlight and I want to grow some vegetables from there (herbs, tomatoes, lettuce). I’ve got a hydroponic system set up and all I need now are the lights. I plan to illuminate the plants during the natural daylight hours and switch it off at night (via timer).
The red/blue LED lighting systems are much talked because they have low energy use, low heat output and supposedly provide all the light energy requirements for plants. But I have no real idea if they work. Some people say they don’t include all the spectrums of light that plants need, others say that they do just fine.
What do the experienced indoor/low light growers use?
My experience with lighting is from planted aquaria rather than veggies, but in my hobby the consensus is that bulbs labelled “grow lights” are generally a scam. You’ll need to research the spectrum the plants need most, and research the lowest cost option for providing that.
Well, the ‘best’ lights are HID lamps but they can be pricey. I’ve had good luck growing tomatoes and chili peppers in a closet with a few CFL lamps. I use six 23w (100w incandescent equivalent) CFL lights, three of them daylight (6000K), three of them soft warm (3000K) to get a more complete spectrum of light.
You also have to be sure to consider both purchase price AND operating cost, When I upped the light on my larger tank I was surprised at how much my elec bill jumped. Also, don’t just assume they need the lights to be on for an extended period. If they are deficient in one part of the spectrum, a limited period of such light might be sufficient.
See, it is more complicated than just adding another bulb. Sorry I’m providing more questions than answers.
Is this an indoor grow rig or an outdoor grow rig?
if it’s indoor, I find that a pair of basic 48" flourescent shoplights on a mechanical timer work just fine. As far as the bulbs go, I tried the fancy growlights first, one warm tube (red/orange balanced and one cool tube (green/blue balanced) and they worked okay.
On the next grow, I switched to basic generic tubes, one “Warm White” and one “Cool White”, there was no difference in growth, and the basic bulbs were dramatically cheaper to boot.
MacTech’s advice is good in general for indoor plant growing. Many plants, particularly foliage types do well under 4-foot fluorescent fixtures using two T-8 cool white bulbs, or one cool white and one warm white. Herbs and lettuce would probably do better under either a four-tube fixture or two 2-tube fixtures placed close together and with the foliage just a few inches under the tubes.
Tomatoes and peppers are going to need more light; otherwise they’ll tend to grow tall and spindly (this process is exacerbated by growing conditions that are too warm, as in constant temperatures of 70F or more).
In fact, temperature and humidity are going to be additional important factors in growing healthy plants. A relative humidity of at least 40-50% and cool nighttime temps (dropping to the low 60s or even a bit cooler) are preferable for best growing of herbs and vegetables.
Part of the problem with high-intensity lighting (i.e. metal halide or HPS lamps) is that they give off a lot of heat, which makes it difficult to grow healthy compact plants. I don’t have experience with LED lamps.
The folks at the Growing Under Lights forum at http://www.gardenweb.com (see under plant forums) can give you more help. There’s probably good stuff in the FAQ section.
I suggest you might need to rethink your plan. I have a hunch that unless you go for an extremely powerful light, whatever light system you try to set up will probably block more light from the sun than the system produces. Lights need to be very close to the plants to be effective; generally a matter of inches, seeking a sweet spot that gets a lot of the light on the plant without overheating it.
You can get a cheap light meter for less than $10 at most any garden shop, HomeDepot, etc., and experiment a bit with the light levels on your balcony and see how close the light bulbs you have around your home would have to be to the plants to provide the same amount of light they would get on the balcony.
A couple alternative suggestions: You might do better to grow plants that don’t need full sun. You might consider growing something like lettuce that would benefit from 24 hour light, using the sun during the day and your grow light only at night … or moving the system indoors and growing under only artificial light. Keep in mind that some plants, like tomatoes, require a day night cycle, while some, like lettuce, will grow like crazy given 24 hours of light.
When it comes to choosing / buying lights for growing, total lumens is more important than fiddling with specific spectrum. Plants getting 1000 lumens from a couple of cheap fluorescent shop lights will do better than plants getting 400 lumens of the perfect mix of red or blue light appropriate to their current stage of growth (more blue light for fast vegetative growth and more red light for flowering / fruiting.) If you are intent on sticking with the idea of artifical light, I suggest trying the cheaper methods first while you learn and gain experience; leave the fancy stuff to the pros for now … a light system costing hundreds of dollars simply won’t be cost effective for your current project.