Plant Lights?

Question

What are the best lights under which to grow plants (specifically orchids and LEGAL house plants)? How close to the plants should the lights be placed?

Answer 1

I use 4' fluorescent shoplights on a wire shelving unit to grow Phalaenopsis, Paphiopedilum, and some of the lower-light Cattleya-types and Phragmipediums. This does not work for Brassavola types and other high-light plants. I use 2- 2-tube shoplights per shelf, with 1 cool white (cheap) and 1 warm-white or daylight (more expensive) bulb per shoplight.

The Catts and higher-light Phrags go toward the center, as the light intensity of the bulbs drops off towards the ends. The Paphs come next, then the Phals at the ends of the shelves. I have several different shelf heights, lower ones for shorter (or out of bloom) plants and higher light (about 12-15" from bulb to shelf works), higher ones (18-24"+) for lower light or spiking/blooming plants, and move plants around as needed. The plants will tell you if they're getting too much light.

Plop a humidifier at the base of the shelf (pebble trays really don't work), and a thermometer-hygrometer (temp/humidity) on one of the shelves- I found one at Wal-mart a couple years back, they're not expensive, but it's great to know what your relative humidity is. Most of the above types like it between 45-60% humidity. Ferns, Miltoniopsis, and cloudforest orchids tend to like it higher than that, but you and your furniture may not, if it's in a main living area...

Answer 2

I grow most of my orchids on my windowledges with natural sunlight. My friends who grow show orchids in their basement use a combination of halogen lights and full-spectrum fluorescent bulbs. They started out with inexpensive halogen desk lamps with the goosenecks standing way up, pointing at the plants. They keep the halogen lights a little farther away because they get very hot. However, this is an advantage in their cooler basement for orchids that like the tropics. Their fluorescent fixtures hang 2" above the trays of plants.

Depending on what habitat your orchids like (tropics, cool climates, mountains, jungle, etc) you can make micro climates with pebble & water trays and proximity to the lights. If your orchids don't like where you're putting them, they will get dark spots on their leaves and look scorched... or will get pale and leggy trying to reach more light.

Answer 3

Not so sure about legal plants, nor about the specifics of the lamps...... but for less-than-legal plants my father used to use the same sort of lights used in incubation pens for poultry and the like.... Large ones with metal coney whatsits. Special heating lamps as I recall... though not the super-hot ones..... and he'd hang them from the ceiling... and coat the walls with foil to reflect the light inward.

I'm sorry I don't know more about the light-bulbs themselves, but I can strongly recommend the foil on the walls... It did wonders for my father's cannabis jungle.