LED Grow Light Forum

Prosource isn't the most reliable source of information, imho. They also claim they can grow top-shelf cannabis at 40w/sqft but the plants show otherwise. I think he's full of nonsense in that video. Most growers keep the room temp at 75-80 with HID but that IS measured at the canopy not at the bottom of the room where it's colder nor the top where it's warmer. With LED, it's no different, temps are still measured at the canopy. So, he MIGHT be right that LED lights MIGHT need higher daytime temps than HID lights, it's *not* because the canopy is warmer than the room.

There IS a theory that the reason LED lights aren't keeping up with the yield of equal sized or larger HPS lights is due to missing IR which the plants feel as heat. Although there are some LED lights that also have IR diodes, I doubt those few, tiny diodes are enough to match the HID lights. Therefore it has been theorized that increasing the LED day time temp during flowering will make up for the lost IR.

RKY is right though; in veg and early flower you want the temps about the same, ~78-80F, day or night, but after a week or two in flower you can drop the night time temps by 10-15F (at the canopy level) this will also help bring out any colors (like the purples and blues) if the genetics has colors at the end.

SisterMaryElephant wrote:Prosource isn't the most reliable source of information, imho. They also claim they can grow top-shelf cannabis at 40w/sqft but the plants show otherwise. I think he's full of nonsense in that video. Most growers keep the room temp at 75-80 with HID but that IS measured at the canopy not at the bottom of the room where it's colder nor the top where it's warmer. With LED, it's no different, temps are still measured at the canopy. So, he MIGHT be right that LED lights MIGHT need higher daytime temps than HID lights, it's *not* because the canopy is warmer than the room.

There IS a theory that the reason LED lights aren't keeping up with the yield of equal sized or larger HPS lights is due to missing IR which the plants feel as heat. Although there are some LED lights that also have IR diodes, I doubt those few, tiny diodes are enough to match the HID lights. Therefore it has been theorized that increasing the LED day time temp during flowering will make up for the lost IR.

RKY is right though; in veg and early flower you want the temps about the same, ~78-80F, day or night, but after a week or two in flower you can drop the night time temps by 10-15F (at the canopy level) this will also help bring out any colors (like the purples and blues) if the genetics has colors at the end.

ok
thank you both of you for your help

let me resume and make sure I understand for the sake of my sweeties

so most important is in vege mode to keep all the time temp 78°-80°F ( 25°-27°C)
and in flowering mode same for -+2 weeks then
daytime 75°-80°F ( 23°-27°C ) and nitetime the lower 65°F (18°C)

at the moment the lower it got at nite time in flower mode is 65.5°F (18.8°C)
so this is perfect no need to make change am I correct?

but vege mode I need to keep them warm at all time so! they get the heater tonite as the temp was 65°F last nite
and day time it get up to a 81-84°F

this as been very helpfull thanks to you RKY and SME for taking the time to answer me

will I push my luck and ask about the height of the lamp?
too low it burns (tested at 10'' ) now they are arround 14-17'' all depends if they are under the 300W or the 180W
and they look good higher I don't think it would be better am I ok?

the PH is important for those who grow hydroponic there is not much influance when you grow in earth?

or it is important......... my water is 7.4 all my others plants grow beautifully ...

thanks again

OH and the genetic I choose that seeds expressely for that she has purple leaves well on the pics if I can get her to give me those colors I would be so very much happy it is red poison

lamp height is just something you have to try. too close and they burn and too far away and you don't have enough penetration. i would think somewhere between 12 and 20 inches. as the plants get bigger, they can handle more light too.

i dont' know anything about soil. SME will have to help you there. but pH is important in soil and hydro.

ladyclaudia wrote:so most important is in vege mode to keep all the time temp 78°-80°F ( 25°-27°C)
and in flowering mode same for -+2 weeks then
daytime 75°-80°F ( 23°-27°C ) and nitetime the lower 65°F (18°C)

at the moment the lower it got at nite time in flower mode is 65.5°F (18.8°C)
so this is perfect no need to make change am I correct?

but vege mode I need to keep them warm at all time so! they get the heater tonite as the temp was 65°F last nite
and day time it get up to a 81-84°F

this as been very helpfull thanks to you RKY and SME for taking the time to answer me

will I push my luck and ask about the height of the lamp?
too low it burns (tested at 10'' ) now they are arround 14-17'' all depends if they are under the 300W or the 180W
and they look good higher I don't think it would be better am I ok?

the PH is important for those who grow hydroponic there is not much influance when you grow in earth?

or it is important......... my water is 7.4 all my others plants grow beautifully ...

I'd say 78-80F for veg and the first week or 2 in flower. After 1-2 weeks of 12/12 then you CAN (you don't have too) raise the daytime temp to 80-85F, with nights 10-15F cooler. If you get too wide of temp swings it can affect yield and stretching.

RKY covered the height; weaker diodes, like in those lights, can probably be closer than higher powered diodes but you can experiment for your grow area and see what works best.

No, pH is VERY important, even in soil. You'll want the soil pH to be about 6.5-6.6


(I might move this to the New LED users forum since it's not really about sick plants.)

sorry for posting wrong place
and you are right I have to do some exprerience since LED are a new for me

I will make sure the temps do not drop more then 5 degree I don't want to stress them
I hope that I will find a good way to make sure the temp at nite don't drop

installing a heater in the tent scares me a little
but if that's what my sweeties wants

and will document more on the PH to learn how to make it to 6.5

will come back and puts some more pics
in a coulpe weeks

Some heaters are safer than others but avoid anything that glows or gets hot enough to cause a fire. You'll want to put it on a timer or a temp controller.