Question about proper height to for maximum footprint.

[Admortis]

Hey guys, I am trying out LED's to eliminate the massive heat problem with HID. I have been growing with a 600 watt hid for some time now and have purchased two Apollo Horticulture 300 watt LED's. I know they are on the cheaper side of things but I wanted to give them a try just to see how things go before I went all out with LED's. The new lights have have 80 3 watt chips at 120 degree angles, so they are actually 240 watt lights I would guess. The area I need each light to cover is 20" x 27" or around 3.75 square feet. I have the lights currently at 14" above the canopy and am at day three under the new lights. I am seeing some of the outer plants starting to lean towards the light. I am thinking perhaps to raise the light to 20" to see if that will give the proper footprint, but my question is at that height will I loose to much par value and end up with fluffy nugs (I am used to rock hard bad boys and anything less is unacceptable). I can always switch to 4 lights (one per tub) but was hoping that I could get the stated footprint with a good yield if I found the right height. Thoughts from a pro LED grower would be greatly appreciated.

 

[Admortis]

Hey guys, I am trying out LED's to eliminate the massive heat problem with HID. I have been growing with a 600 watt hid for some time now and have purchased two Apollo Horticulture 300 watt LED's. I know they are on the cheaper side of things but I wanted to give them a try just to see how things go before I went all out with LED's. The new lights have have 80 3 watt chips at 120 degree angles, so they are actually 240 watt lights I would guess. The area I need each light to cover is 20" x 27" or around 3.75 square feet. I have the lights currently at 14" above the canopy and am at day three under the new lights. I am seeing some of the outer plants starting to lean towards the light. I am thinking perhaps to raise the light to 20" to see if that will give the proper footprint, but my question is at that height will I loose to much par value and end up with fluffy nugs (I am used to rock hard bad boys and anything less is unacceptable). I can always switch to 4 lights (one per tub) but was hoping that I could get the stated footprint with a good yield if I found the right height. Thoughts from a pro LED grower would be greatly appreciated.

Just to add, I raised the light to 18" just after posting this to see if it would stop the lean. If I went with one light per tub the coverage area would be a mere 20" x 13" or 1.8 square feet, which seems a bit excessive for a 240 watt light. Although, the actual electrical draw is said to be 170 watts which at four lights replacing the one 600 watt would only have them over by 80 watts.

 

[smowstack]

Just to add, I raised the light to 18" just after posting this to see if it would stop the lean. If I went with one light per tub the coverage area would be a mere 20" x 13" or 1.8 square feet, which seems a bit excessive for a 240 watt light. Although, the actual electrical draw is said to be 170 watts which at four lights replacing the one 600 watt would only have them over by 80 watts.

i grow under led and will never go back to hid, but I have never found an led that will out perform a 600w mh/hps.

 

[Growmau5]

Respectfully, you must not be reading these forums very thoroughly. There are many people here that are outperforming 600w HIDs. Using 300-500w cob panels.

 

[puffenuff]

@Admortis

I suggest keeping the lights at their current height if you have enough coverage as is.

If you are looking for those dense buds you are used to, you'll need those lights pretty close to the plants during 12/12.

The big thing is to give them enough intensity without causing damage or problems. And don't get discouraged with all LEDs if this run isn't up to your standards. Usually takes a few runs to get it dialed in.

 

[Admortis]

@Admortis

I suggest keeping the lights at their current height if you have enough coverage as is.

If you are looking for those dense buds you are used to, you'll need those lights pretty close to the plants during 12/12.

The big thing is to give them enough intensity without causing damage or problems. And don't get discouraged with all LEDs if this run isn't up to your standards. Usually takes a few runs to get it dialed in.

It appears at the 18" mark the lean from the outer plants has stopped so I am thinking this is going to be the correct height for this footprint. In you opinion is 18" a good height for a 300 watt LED?

 

[Admortis]

Respectfully, you must not be reading these forums very thoroughly. There are many people here that are outperforming 600w HIDs. Using 300-500w cob panels.

I would have to agree with you Growmau5. I know that the LED is going to do a better job than the HID did, my question was more pertaining to the correct height to achieve the footprint while maintaining the maxim PAR values.

 

[smowstack]

It appears at the 18" mark the lean from the outer plants has stopped so I am thinking this is going to be the correct height for this footprint. In you opinion is 18" a good height for a 300 watt LED?

it's a moot point in someways. If I let the canopy get closer than 18 inches from the led it will start bleaching my leaves. So, 18 inches is about the minimum. You can expand the foot print by raising the light. I figure, 18 inches covers about 2x2.

 

[Growmau5]

@Admortis Here is a photo just for comparisons sake. i'm running cobs, so its a little different. but basically:
top buds: 16" from light
rest of the canopy 20-24"

When my plants were younger ( veg to week 1 of flower) I had to run 30" from the canopy or the entire plants became much lighter in color. It was a uniform bleaching event, not just the tops.
Strains: La Blanca, Grape Stomper x G13, and a Querkle cross.

 

[Admortis]

@Admortis Here is a photo just for comparisons sake. i'm running cobs, so its a little different. but basically:
top buds: 16" from light
rest of the canopy 20-24"

When my plants were younger ( veg to week 1 of flower) I had to run 30" from the canopy or the entire plants became much lighter in color. It was a uniform bleaching event, not just the tops.
Strains: La Blanca, Grape Stomper x G13, and a Querkle cross. View attachment 3460577

That is exactly what I needed to know. Appreciate your input buddy