Can someone advise me about my light

Question from a fellow grower:

Hey a quick question…I’ve tried twice now to germinate indoors using a
rapid rooter but not peat plugs or rock wool. I intended to grow hydro.I would
put them in the rooters, wet the rooters, squeezing off excess moisture and
keeping them dark. I started checking them after the second day and when they
would sprout I would put them in their hydro pods with air and water pumps. I
would start using light from a 400watt(the first time HPS light). the stems kept
growing fast and thin, had no support and died after a few days and keeping the
light about 2 ft above the plants, forgot I have a grow tent. I have an
adjustable ballast on the light and can turn down wattage to 200( 2nd time) with
the light the same distance as before(2 ft. above) same problem, they died.
Another thing I noticed that it was impossible to control tent tempeerature even
when using gale force fan attached to light and taken out of the tent, used aq
second smaller fan to circulate air in tent and a 6” inline fan for exhaust from
the tent. temps would get to 84-86 F. I do have a 4ft fouresent light with samll
wattage grow bulbs that I can use…do you think that might work better for
the first couple of weeks to get them growing then switch back to the HPS
light…Help, I’m really frustrated but not willing to give
up…I also have a outdoor plant grow (8)going now
that is moving along ok and just entered the flowering period. I have used the
defoliating and fimming techniques that are working as taught and are starting
to increase amount and size of buds…any advise you can give me would be
gratefully appreciated…

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Growing thin could be heat or lack of roots. Root temp should be between 64 and 70 Fahrenheit. Ph should be around 6.0 for hydroponics.

The more light you have the more demand it puts on the plant and if there isn’t enough of everything else" co2, nutrition, oxygen at the roots,and the ability for the plant to use what nutes are at the roots(ph) " that would create a weak link.

Hi, when I start my seedlings I use a 50 watt cfl it’s strong enough for seedlings. Then increase the light as the plant grows. A small plant can get too much light. It’s also easier to control the temp with the smaller light. good luck.

Take care.


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  • air must be replaced/re-circulated every 30 seconds - sounds like heat , light issues are common with using “tents” - it takes a bit to get the hang of your grow space. there is a formula for air circulation called “cfm’s” to figure your proper air movement/exchange for your specific grow space —size of tent? Temps to high i day time . might need a bigger fan system - then look at you light distance from plants . also cfm’s are located on your bulbs loght

Thank you david

A friend gave me these. Two bulbs and a ballast. My question is, is this even worth my time?

The space I am considering is about 4’ sq. I know that no matter what the light would have to be as close as possible, but is this gonna be enough to spend my time on?

I guess I should learn to use the preview option.

There is a formula for how many lumens per square foot. I grew one plant in a 4 by 4 closet and the 400 metal halide had around 35,000 lumens and I’d bet that you could do OK with half that.

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