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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.
Place your hand palm down on top of your tallest plant. If you can keep your hand under there for 2 minutes and the back of your hand does not burn, you can lower the light as continue to do so until it just begins to feel uncomfortable after 2 minutes. Now, if that causes your leaves to start doing the upward curl, then raise a couple of inches and continue doing so until the leaves settle down. However, they will still seem to be reaching for the light and that is normal. Good luck! Take care and be well....
Without a decent exhaust fan and passive intake, your temperatures will not only be too high, your plants will also lack oxygen. In addition, if you don't get a carbon filter, the smell will give you away in a couple of weeks.
My 400W HPS is a little over a foot away from my babies' tops. I have a 410m3/h exhaust plus passive intake. They are now 2 weeks old, plus 1 initial week of germination, and grow bushy without a heat problem. Nevertheless, I had to add another intake because it wasn't enough - with that, my temperature is now around 26 degrees celsius - ideal for my girls.
Imho, a 400W HPS is not suited for no-budget grows because it really heats up your cabinet. Either change lamps (someone else has an idea?) or spend some money...
I have hung my 400w HPS 2 feet above the tops and adjust as the plant gets bigger, but I also have a carbon filter and fan. My temps are around 80 in a 3x3x7. Fan and filter are canfan's.
My 400 watt HPS is about 6-10" away from the canopy. It could be closer but I lose to much footprint. No aircooled hood. Just a bigass 16" fan blow over it.
I have a 400watt HPS and i just want to know will this do for veg and for flower? and how far do i keep it away from the plants in both stages of growing. thanks
Works fine for both......I like at least 15 inches....but you have to watch the temps, between lights and plants. Cool air between lights and plants is best.Quote:
Originally Posted by DonSmokin