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I have a 400 watt hps lamp and wondered what is the ideal distance between the top of the plants to the lamp ? I cannot get my lamp very close to my plants as they curl upwars and i posted this on here and LIP said this was because of the heat. I don't want the plants to stretch so if anyone knows the ideal distance that would be much appreciated.
Cheers
Bob
Depends on your setup - what else does your system consist of? Vent, size of passive intake, etc?
What you could do is point a fan at the bulb. This should lower the heat a little, so you could get it closer. Basically, get it as close as you can, as long as the tops of the plants are at 75F.
cheers, can i ask approximately how far away as i do not have a temperature guage to check? it says 2 inches in some books but i have the lamp about a foot away and the leaves still turn upwards. This must be for CFL lamps. Just an approximate because then i can alter slightly to test to see if the leaves do point upwards or not. Cheers LIP uve helped me out loads of times lol.
Cheers
Bob
Again - there is no rule of thumb if I don't know your ventilation setup. I have a 410m3 fan plus passive intake, which means that I can keep the temperatures okay - my 400W HPS is placed app. 35cm away from the tops, and they are doing great. Your biggest risk is heat.
my set up is in 400 watt lamp in a wardrobe, no fans or intake filters. I think ill get a fan and aim towards the bulb like LIP said to remove a bit of the heat.
this link might help you . the postman
http://www.medicalmarihuana.ca/lighting.html
When u use HID bulbs, ventilation is the key between the bulb and the top of ur canopy....use extractor fans (pc fans usually cheapper) and also rotating fans to cool of the bulb this is crutial if u want to keep a 400watter in such a small area....otherwise u will scorch ur plants
Here's the thing, you need to take air out, the best way to do this is too use a cool tube or an aircooled reflector, the draw back of these thing's is that air flow going through ducting, tubing, is noisy, and secondly, regardless of how well designed bulb cooling systems are, light lumens are intercepted as soon as they have to pass through glass shields, you would do best with one or two, or three pc fans or a single fan blowing on the bulb, and an extraction setup at the top of your room. The closer the bulb is too the extraction system at the top of the room the better, hope this makes sense. Someone mentioned 75 degrees, and as your growing in a wardrobe, your at the mercy of outside weather conditions, you have littler control over fluctuating temperatures in your wardrobe, if you can get the temperatures within ideal ranges of 75-80degrees this would be beneficial, but if you can't tackle the heat that 400w bulb will give off, just make sure the temperautres stay below 90.Quote:
Originally Posted by bobbyhardcore
if i was you i would hang my lamp right at the top of your wardrobe they will not stretch too far they will only stretch to about 8 inch then start bushing i have my lamps on the ceiling in my grow room and my plants are a picture of health very bushy.