I'm attempting my first grow but I've hit a big problem. I'm trying to grow two or three plants at a time so I've set up a small wardrobe (800mm by 500mm by 1500mm), lined it with mylar and rigged up a 100mm fan with a carbon filter. Going on the 'more light the better' principle, I installed a 400Watt MH light and have therefore effectively built an oven! The temperature inside reaches nearly 100F which I know is way too much. Two questions; Will swapping out the MH bulb for a HPS make much difference or should I just swap it all for a 125W CFL light? Will the three seeds I stupidly put in there to germinate before checking what temperature it reached, have any chance of germinating? I removed them when I noticed the problem 24 hours later but I suspect the damage has been done. I may cry if they come to nothing because three feminised White Widow seeds don't come cheap! All advice gratefully received
No. No way. Stick with the MH, and install ventilation capable of dealing with it. Is this 100mm fan a PC case fan, or a decent inline duct fan? Hahaha, I've cooked my share of seeds, but I'm not sure at what temps. All you can do is wait and see, but I don't think that 100f would be enough to kill an ungerminated seed.
It's an inline duct fan but I suspect not a particularly good one. It seems to shift a fair amount of air but even with the intake right next to the bulb it doesn't reduce the temp by much. Even with the light as high as possible, the temp at the bottom of the box is still 95F, so when (if!) the plants grow, the tops will be much hotter. Any reason why CFL isn't a good option? I know they produce a lot less usable light but they're also a lot cooler and seem to be a better bet for such a small box.
Seeds are bound to be fine. How are you germinating them? Did you read the sticky on germination? Kitchen paper, dampened, in a tupperware type tub, somewhere warm (radiator, PC monitor etc.) works a treat. Take Rabiez advice for sure about the lights!
From what I have read MH/HPS is for faster growth and higher ields. My first grow is vegging great under 400W MH. I had similar heat issues and still find it a bit awkward, but it helped a lot getting a reasonabley powerful desktop fan. Aim that at the light. Move the light further away from the plants if poss....oh hang on, no plants yet! LoL! I have the desktop fan as well as the in line extractor with carbon filter.
Using a good quality soil in small, compressed peat pots to germinate the seeds. Not sure I've got room in the box for a desktop fan but I'll look into it. Would it help to open up some more vents in the box to allow more air in?