I have a 6’ x 7’ room (1.8/2.1 m) that I want to heat and light to bring my outdoor potted plants in for winter. How much light do I need? Will a 150 watt r40 flood light do the trick? Hibiscus mainly.

  • If you want the plants to grow actively during winter, the light requirements will probably be "a lot more than you imagine". A single 150W bulb will only light about 4 square feet (i.e. 2 ft x 2ft) of the planted area - i.e. if half the area of your room is plants and the other half is for access, you would need about five 150W lamps. You might then need cooling, not heating, to maintain the right temperature! – alephzero Sep 17 '18 at 21:09

We have a similarly sized grow room; 6X10 feet. We run one hp sodium at 600 watts (works for about 3 square feet), another T-5 fixture with 8 bulbs of proper seasonal spectrum, starts and germinating have T-5 fluorescent with 4 bulbs each 50 watts/bulb so 254 watts per 4 bulb fixture; 8 bulbs would be about 500 watts. Why this can't be more precise I still don't understand...

The room is insulated with 6" batts, white plastic stuff on the exterior facing the room (reflects light).

During the winter we have small heater in place. LEDs are becoming popular but they don't provide heat, neither do the fluorescent fixtures. The HP Sodium does. You need to be able to raise and lower the fixture to maintain an optimum distance not too far not too close of the fixture to the plants. Easy to burn apical tips of plants.

Hubby put in an air intake and an air outtake to keep the O2 being taken out so fresh CO2 can be taken in and next to the photosynthesizing leaves for use in photosynthesis. Otherwise the excess O2 slows the processes that need CO2 down.

Also have 2 big fans and 4 little fans. Grow rooms without moving air (moves your hair strength) will get fungus and slower growing plants.

So 150 watts is pretty lightweight. And a security light bulb is not a grow light bulb. Much more science about the light spectrum is involved with artificial lighting in a completely artificial environment is necessary to understand. Not tough, honest. Gets very interesting.

The best manual/textbook I've found to explain growing plants in a grow room is called; The Cannabis Encyclopedia the author is Jorge Cervantes and other experts who collaborated on an inch thick 8 1/2 inch X 11 inch book all about growing ONE plant. This Cannabis stuff is making great gardeners, seriously.

If you want to do a grow room making as few mistakes as possible, I would go order this book! Everything you need to know about lighting, fertilizer, soils, how to ID problems, air, actually basic down to earth how to grow plants, even hydroponically. Nuts and bolts of the mechanics, room designs and from germination or cloning to harvest.

  • I would suggest a metal halide instead of sodium for a plant growing spectrum. When my company professionals grew indoors they used metal halides ( I don't remember the temperature color). Aquarium suppliers are another place to get lighting information and supplies. – blacksmith37 Sep 19 '18 at 19:14
  • Humor - When Amoco bought a dozen 1000 watt metal halides lights, the DEA came to inspect what was being grown. – blacksmith37 Sep 19 '18 at 19:17
  • major chuckles black! they come to inspect if someone has a spike on their electrical usage. They are able to see heat signatures for grow rooms. Big Bro is certainly watching... – stormy Sep 20 '18 at 4:22

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