Answers about CFL, HPS, How Much Light...

[Roughrider]

First--28" high and you're still in veg? Wow...that's going to be a serious plant.

With a plant that size you will definitely, 100% need more light, especially below the canopy. Even though the bulbs you list (which are interesting, btw) are considered spotlights, I just don't see you getting heavy canopy penetration from a 20w bulb.

I also wonder if you're going to outgrow that area. You're going to get some stretch and bushing out. A 28" plant should grow at least 1.5 times in height in flower...it will probably double in height or more, depending on the strain. A 4' plus plant is probably going to need more than a 24" x 24" area. And I stick with the basic lumen information...if you end up using 28" x 28" (which I think you'll need for a plant that size), that's around five and half square feet. That would mean at least 10 bulbs like that; 15-16 would be a whole lot better. For cuttings, if you plan on staying in the 24" x 24" area...that's four square feet. At least 7 or 8 lights; 10-12 would be best. I'd think about having 65-75% of the lights on top, and 25-35% below the canopy as supplemental light.

I've used CMH bulbs. 3000k is pretty normal for those types of lights. IMO, they're as good as MH for veg, but not quite as good as HPS for flowering (close, though..more than good enough). They run cool, which is nice--and you'll want to get the lights close, since they're only 20w each. You'll need plenty of lights though, as I said, so be sure and check temps and have some air circulation. Good luck!

[kwaaluudekid]

Thanks for the info, it is MUCH appreciated. I was going to start the flowering stage this weekend (they'll be 6 weeks old then). space really isn't an issue yet, they're in the garage and I use it as an office, so I'm the only one ever goes in there. right now they're just tall and lanky, but hopefully they'll bush out. I'll try to get some pics up if I can. I'm guessing these lights prolly wouldn't be too good for a trunk setup? the trunk is 13x17x31. I'm also growing in soil for now, but want to try DWC for the next grow. Any suggestions? again...thanks for your help

(it said I uploaded pics...but they're a month old when plants were only 2 weeks old...will show more pics in "my grow")

[kwaaluudekid]

here's some pics of my cmh grow. the 1st one shows height. 2nd shows whole plant. 3rd shows top of one. 4th show popcorn bud...kinda spindly, but with any luck will bush out nicely

[calbunn]

have you done a grow with induction grow lights? theres some induction grow video on you tube if you've not see them and the 166.5 lumens per watt is higher then anything short of plasma without the heat.

[StoneMeadow]

I have a few interesting data points for cfl and fl bulb fans. After reading some cfl grow threads where the plants suffered from burning if the bulb is too close to the plant, I decided to measure some bulb temps directly. Using a good quality surface pyrometer on stabilized bulbs (on for about an hour), I get 84 degrees F for a 34w 4100k 48" T12, and 104 F for a 14w "soft white" cfl. I guess I now understand why a T12 can be dropped right down into physical contact with the tops of the plant without causing burn, and why any cfl must be kept several inches from the nearest leaves.

[gypski]

I have a few interesting data points for cfl and fl bulb fans. After reading some cfl grow threads where the plants suffered from burning if the bulb is too close to the plant, I decided to measure some bulb temps directly. Using a good quality surface pyrometer on stabilized bulbs (on for about an hour), I get 84 degrees F for a 34w 4100k 48" T12, and 104 F for a 14w "soft white" cfl. I guess I now understand why a T12 can be dropped right down into physical contact with the tops of the plant without causing burn, and why any cfl must be kept several inches from the nearest leaves.

Then you'd want your T5 a distance that at the canopy was in the mid 70 degree range. Distance does matter!!!!! imp:

[jon420]

Dsitance and amount of light is the biggest step for growing with CFL's and floro's. I know that there are huge debates out there about using CFL's & floro's for the whole grow. Most people do great when it comes to vegging but when it comes to flowering time, a lot of people are dissapointed. Flowering with cfl's & floro's is not much different than flowering with HPS. Only difference is, the HPS penetrates further from the light source which means you don't need much side lighting, if any. A lot of people grow from above the plants only and that is where the CFL & floro growers make mistakes. CFL & floro grows should penetrate the plant from all sides if possible and as close as possible (CFL's do burn but haven't seen a floro burn yet). I have seen CFL & floro grows turn out just as good as HPS grows, if not better and of course less lumens and watts. It all depends on distance and amount.

I have seen 467watts (34,XXX Lumens) of CFL's & floros combined to make the goodies and amounts you see in magazines, no lie, it can be done!!!

[headshake]

(CFL's do burn but haven't seen a floro burn yet).

my t-5s have burnt leaves, but only when leaves are touching them directly for prolonged periods of time.


-shake

[jon420]

my t-5s have burnt leaves, but only when leaves are touching them directly for prolonged periods of time.


-shake

Sorry, I should've specified. I have not seen a T12 burn yet, my bad. I have heard of the T5's burning and even the T8's but never a T12.


CFL & Floro Grow Log Coming Soon!!!

[brynpav]

Dsitance and amount of light is the biggest step for growing with CFL's and floro's. I know that there are huge debates out there about using CFL's & floro's for the whole grow. Most people do great when it comes to vegging but when it comes to flowering time, a lot of people are dissapointed. Flowering with cfl's & floro's is not much different than flowering with HPS. Only difference is, the HPS penetrates further from the light source which means you don't need much side lighting, if any. A lot of people grow from above the plants only and that is where the CFL & floro growers make mistakes. CFL & floro grows should penetrate the plant from all sides if possible and as close as possible (CFL's do burn but haven't seen a floro burn yet). I have seen CFL & floro grows turn out just as good as HPS grows, if not better and of course less lumens and watts. It all depends on distance and amount.

I have seen 467watts (34,XXX Lumens) of CFL's & floros combined to make the goodies and amounts you see in magazines, no lie, it can be done!!!

Your post got me thinking about surface lamp temperatures since I've been using inda-gro 400 watt induction fluorescent lamps for the entire grow and I let the plants grow within 12" of the fixture @ week 12 with yields consistent in the 300 g/m range. I'm on my fourth grow now.

Electrode-less induction is really fluorescent lamp on steroids emitting 166.5 VL/W, 95% PAR usable UV/IR spectra, which like an HPS gets excellent canopy penetration but still runs much cooler compared to HPS operating temps.

With lamp surface temps having much to do with fixture design, room size and ventilation I can speak only to my particular room/lamp combination. And while I don't own a pyrometer for a lamp surface temp I don't let my plants actually touch the lamp anyway. The measurements I can give though are from readings I took with an infrared thermometer.

I have a 90 cfm fan providing a reasonably well ventilated 10 x 10 x 8 (800 CF) grow room with an maintained ambient temperature of 78 degrees F, I measure 80 degrees F @ the nearest edge of the reflector surface approximately 1" away from the lamp itself.

I was told by inda-gro was that these lamps actually function best, in terms of MAX lumen/watt output is that the room be ventilated to not directly remove the surface temperature of the lamp to where it falls below 70 degrees F.