E-mail -- A need for cooling the closet?

Hi Doc,

I am looking to purchase a 400 hps light set from HTGSupply.com and I was wondering if it would require cooling if it is left in a 12-12 cycle. I am limited in terms of cooling as I do not want to destroy my closet and am not able to drill anything. How could one go about cooling this machine for under $50 effectively?

 The 400 HPS is a good all purpose light. The answer to your question depends on the size of your closet. I also have a 400 HPS in a closet that is 4X10X7.   I have a carbon filter and duct blowing over the plants at the bulb to move the heat around and my temperature never gets above 85F if I leave the door shut 24/7. That may seem high but it is ok for most plants. It would be a good idea to get a thermometer from HTGsupply.com that has a minimum and maximum reading and put it in the closet. If the temperature never goes above 90F you are fine. If it is over 100F, and you are not growing cacti, your plants won't grow to their full potential. (This means you need to do something).
Keep in mind the temperature by the plants is what you need, if it is 100F+ at the top of the closet but two feet under the bulb it is 85F by the plants you are fine.
If your closet is a small closet and your temperature by the plant tops is over 100F you have to do something. The easiest thing is to have the door open during the 12 hours ‘on’ cycle. If you can only open the door for a short time the best time for this would be near the end of the light 'on' cycle when the temperature will be highest. The problem is you may forget to shut it and irregular dark and light cycles will lead to plant stress which will lead to poor plant growth and flowering.  Keep in mind, it would be better to have a few ‘hot’ days then changes in day length.

The next thing to do is to use a fan to move the heat away from the plants. The fan and door open will work better together. You can also try raising the light higher above the plants to see if this cuts down on the heat right by the plant tops.

If you have a small closet and think the temperature will be 100F or more and having the door open is not an option, you may want to use T5-HO fluorescent lights. You can get flowering bulbs that are high in RED light if you are interested in flowers. I say this because I had a small closet (3x3x7 feet) once and even a 250 Watt HPS needed to have the door open or it would get close to 100F by the end of the lights on cycle.

I should also mention finally that I think a 150 watt LED or two might also be an option if you are worried about heat.

Good Growing,
Dr. E.R.Myers

Yous could also send an E-mail to Sales@htgsupply.com, the sales manager Perry knows how to use all sorts of equipment and might have something in your price range.

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