Canachris
Well-Known Member
My sunny day has gone cloudy... I dug my 250 mh light out of the closet and I'm not sure how much distance between seedlings and light...
250 MH light distance from seedlings
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Sueet
Well-Known Member
I've never used mh for plants, but my experience with them in a fish tank is that they produce a LOT of heat ... just make sure the heat isn't gonna fry the babies... put your hand where leaf level is, if it is comfortable for you, it is probably fine for the plant.
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Canachris
Well-Known Member
I have it at 16" and it's not too hot on my hand. I've used in the past but I can't remember the distance. Sux getting old
Sueet
Well-Known Member
Yes, yes it does.
I'd move it upward until that thermometer read about 75-78F, as long as they don't start to stretch.
16" is fine. I ran a 250-watt HPS at 10" to 14", and my seedlings showed no signs of suffering. Started at 14", let them grow a bit, then raised the light, which accounts for the range in my previous sentence. No bleaching was observed.
As mentioned, one still needs to be aware of heat. Seedlings have almost no ability to self-cool through transpiration, due to the few leaves and roots. Basically, with a small HID like that, if it's not too hot, it's most likely not too bright, either. But, as in most things, "YMMV" applies - so generally keep an eye on them.
As mentioned, one still needs to be aware of heat. Seedlings have almost no ability to self-cool through transpiration, due to the few leaves and roots. Basically, with a small HID like that, if it's not too hot, it's most likely not too bright, either. But, as in most things, "YMMV" applies - so generally keep an eye on them.
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Canachris
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I have a fan on them now and the temps are are around 80. Thanks for the input guys these first few days are the most stressful
Fuzzy Duck
Well-Known Member
Wow that is really old fashion lighting 
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Canachris
Well-Known Member
hahaha I know it's been in my closet for 3 years, forget what year I got itWow that is really old fashion lighting
Any idea how many hours on the bulb? It's fine for up to eight square feet, more or less, during the growth phase (not going to win any races, but...), but that assumes the bulb output hasn't significantly degraded. Unfortunately, that's not something we can spot by looking at the bulb while it's in use - it'll still "look bright."
Of course, for two baby sprouts, lol, it's overkill, regardless. A 23-watt CFL an inch above each, in a horizontal orientation, would be fine for a week or longer. Especially if you cut a beverage can, open it up like "wings," and attach it to the base of each bulb as a low-budget reflector.
Of course, for two baby sprouts, lol, it's overkill, regardless. A 23-watt CFL an inch above each, in a horizontal orientation, would be fine for a week or longer. Especially if you cut a beverage can, open it up like "wings," and attach it to the base of each bulb as a low-budget reflector.
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Canachris
Well-Known Member
Hey tourt , I mark the time used on the box the bulb was in. This bulb had about 6 months of use but the 250 MH go for 18 hr's a day... but after all this shite i noticed this morning the light is pulsating and the off/on switch is frozen, it don't click off an on anymore. I'm going back to my LED Quantom board.
