i just started growing in a pc grow box and im totally new to growing, i have a 15w bulb, i think it is a CFL bulb and i only want to grow 2 plants.. it says 15w=75w and 6400k/820lm/55lm/w on the back.. do i need a bigger light? more lights? or is this one okay???
One 15w spiral fluorescent can start four seedlings, veg one average-sized plant, and is insufficient for flowering any. The problem with flowering under most CFL's is that their light doesn't reach very far. With most fluorescent grows, there either needs to be an atypical high-wattage fluorescent capable of supporting taller plants, light sources at different levels to provide light to lower parts of the plants, and/or plants trained to be very short.
Personally, I'd increase the number of plants to four and flower under an HID. A single HID bulb covers a fairly square area. A 400w HPS can support maximum growth over a 2.5x2.5' floor area and flower 2' tall plants very well. A 250w can handle four smaller plants in a smaller area moderately well. If you want to stick with two plants in a simple grow, fluorescents might be the best way to go. Like I mentioned above, there are a few ways to go about it and all of them can get through flowering if set up correctly. Just one to a few high wattage floros would be best. Trichomes are like genetic sunblock and their growth responds to light intensity, so packing emitted light into fewer light sources results in greater potency than the same amount of light emitted from a larger area. What wattage you'd use depends on many factors like plant height at harvest, floor area and what kind of fluorescent bulbs you choose.
If you're doing a pc grow, you need about three or four 23-26 watt cfl's in the 6500k range for veg. and a little more 2700k range for flowering. if it says 75 watt equivalent, don't listen. Only look at the actual wattage and just curious, do you know how many lumens it gives off? The general rule is 100 watts per plant and an extra 50 watts per plant after, altough it is ok to have less wattage in that small of a space. But in that small of a space, cfl's are definitely the way to go. No HID bulbs mh or hps, and no room for fluoro's. Although, leds are very cool and low temp.
And I just saw that it was 820 lumens, definitely just upgrade your few cfl's. You can get a four pack at lowes or wal-mart.
