Hi all, I've just started my first ever grow. I've been reading up on everything and I think I have a pretty good idea what I need to do (at least for the initial stages of growth). But, the one thing I can't find much solid information about is what kind of lighting I need for very young plants (that is, from seed until the plant is established and the veg stage starts). I have a 600w HPS, and a coupla 'daylight' CFLs (6000k, 32w, 1800 lumen), but I'm unsure which to use when.. My plants have only just germinated and started to break the surface of the soil. I haven't switched on the HPS yet, just hung the CFLs a few feet away (I didn't want to overdo it as they're still really young). I'm really not sure whether I should be placing the CFLs as close as possible now, or waiting until they're a bit bigger. I'm also unsure at what point I need to switch on the HPS. If anyone could give me some tips I'd be most grateful!
You'll be able to tell when they start stretching. Test the HPS and make sure it doesnt get your grow area too hot. Then you'll have to play around a bit with the distance from the plants.
The HPS takes the temps up to 32-33C (90F), but that's with the intake pulling air in from the room. There's a bit of scope to make it cooler by pulling air directly from outside, but doing that will mean I have to switch the fan off when the light is off, or it'll drop well below 20C (68F), so I'm not sure what the best choice is. Better to keep the temps lower when the light is on, or reduce the airflow dramatically when it's off? You're saying I should forget about the CFLs and just put the HPS on 18/6? Even when they're really young? (most of them are only just peeking through the surface of the soil at the moment, although I'm sure that'll change soon enough ) Thanks for the reply, btw, it's very much appreciated
Well I would use the CFL's till they unfold their leaves. That way you'll be able to tell how they're reacting to the light. I started with my 600w MH about 30 inches away and they stretched, and now it's at 11 inches. So if a MH is at 11 inches I would think your HPS would be almost double that? It really all depends on how cool you can keep the area under it. Sorry really baked right now so if that didnt make sense then uh yea....
Ah right okay cool. So wait until they've either reached an inch high or so (or if they start stretching) before turning on the HPS?
Yea, I'm growing some of Barneys G13 Haze right now and I put my 600w on them when they were about two days younger than this. You can see they stretched a little when my 600w MH was 30 inches away. Make sure you stick your thermometer right next to your plants to get a good estimate of how much heat they're getting
Ah thanks for the pic, that helps a lot. I think they're stretching a bit, but having never done this before, I really don't know. My light, although an HPS rather than MH (I'm told these HPS bulbs are okay for vegging as well as flowering), is about the same, 30 inches or so away at the moment, and the thermometer (which is only a few inches from the pots) reads about 29C (85F). Here's one of mine, kinda hard to see under that orange light, I know, but it's about 1.5" tall: Is it worth lowering the light a bit? I'm not really sure if the increase in temperature would be acceptable or not. Most of the stuff I've read says keep it to 20-25C, and it's already above that. Thanks for all your help so far, by the way, it's been very useful indeed!
Your plant looks great! Not much stretching at all. I just kept lowering my light as far as it would go without exceeding 80 degrees. I burnt one of my leaves on a smaller plant when I got down to 11 inches. I raised it up to 14 or so and I cant even tell what plant was damaged. So really it's just trial and error. Make sure you write down your measurements with their age so you can have a good idea for your next grow
I don't know if you can tell from this pic but the leaves started to fatten up when I moved the light closer, so much that I had to cut up some grow labels and stake them. Sorry for the shitty quality of all my pics. Camera phone + MH light makes black lines and bad quality!
Ah, great, that makes me feel much better Excellent idea, I'll do that, thanks Mine's about 85F at the moment, should I be looking at ways to reduce the temps (or raising the light), or will they be okay with 85F?
Some people will tell you that that's to hot but when you look at where MJ grows I think it's fine. Just make sure you're monitoring them. Also don't spray them when the lights on. I think that's where my burn came from On a side not im waiting for my soil to warm up becuase it was in the garage. Then I can add like an inch in each container. Then I can go smoke a bowl
Okay, thanks man, I'll keep an eye on them. I got some ideas for drawing in outside air which should help (it's damn cold here at the moment ) To 'undo' the stretching? Nice Gah, jealous, I wish I could do the same dude. Got no supply around here , that's the reason I've embarked on this little grow operation.
Yea prices are really high around here. Like 60 for an 1/8 Yea it's to undo stretching but I also just dropped my ducting on a plant and i'm sure the roots aren't liking that at all. Hopefully it lives but the extra soil will help cover up the damaged roots. How many plants you got? I only have six so I really don't wanna lose one
Noo! that's well harsh man, I hope your plant survives! Only 5 at the moment. I have more seeds but I didn't want to go overboard first time as I'm pretty sure I'm going to fuck it up at some point Good work
So you're basically trying to balance out two factors here, heat and lighting. Heat, the plant could do with out, lighting not so much as it is one of the main ingredients. No matter how high or low the light is, that bulb is still gonna be generating heat. Of course the heat would be relative to the distance from the plant but heat will be generated nonetheless. So what to do... Place the light too high and your plant will stretch, too low and it might burn the leaves as well as cause the plant to experience some kind of heat stress (if the temperature gets high enough) Find a balance between the two, a sort of compromise. How about placing a small fan on the plant to blow off some of that warm air..? This will also help strengthen the stem. best of luck