400w marijuana grow lamp?

A question from a fellow grower:

I was wondering if a 1000w lamp is necessary, or if I could go with a 400w lamp as well? I realize that more light provides a better grow, but I was just curious? I’ll be growing the plants in my bedroom, and ventilation with a vortex fan won’t be a problem. The climate here in Hawaii is ideal I’m sure. During germination, I suppose that I’ll need to start with a makeshift CFL lamps until the plants are about 6 inches tall, and then switch to the HPS lamp. The garden supply store I visited a few days ago also recommended the halide lamps.

A 400w lamp will work fine in most smaller grows. Check out LateWood’s response to a very similar question for a nice easy to follow general guide for how much light for how much space http://www.ilovegrowingmarijuana.com/community/topic/watts-per-square-feet/#post-16065

Thanks for the tip and the link. This being my first effort, I’ve decided to go with T5 fluorescent lighting. Depending on my success, I may then use a halide lamp for future grows with a combination of both.

Thanks for the Kudos, McG. :smiley:

T5 is a perfect veg, seedling, clone, Mom lamp set up. So you are in great shape for early stage growth.

In flower the T5 is extremely week. However; It will be real easy to have a safe grow. What you want for flower is an HPS lamp, not MH. Good Luck

I bought a 400w auto-switchable MH?HPS digital lamp “Ipower” brand, off ebay for around a hundred bucks including: 1 400w MH lamp, 1 400w HPS lamp, 2 adjustable hangers, 1 reflector hood, and digital ballast with long power chord. The ballast can be switched from 200w to 300w to 400w, by turning off lamp and letting cool, then change settings on ballast.

Also All you do to go from veg (MH) to flower (HPS) is change the bulb. That’s right, nothing to switch. Had my very inexpensive Iposer digital system for over a year with no issues.

Hope this helps. Peace.lw

Thanks lw. I found the MH/HPS kit you were referring to. I’ll check locally to see if I can find something that’s even comparable. Is there any reason to go below 400w (aside from cost) during the flowering stage? Just wondering.

UPDATE: Not knowing first hand, I’m thinking now that heat might also be an issue. When you advise switching the ballast, can that be done let’s say, from 400w to 200w, during the last 2 hours of the light cycle?