LED light height

[johnw2269]

Hi
I have a 4x2x6 grow tent and I'm planning on running 3 300w Mars led lights on top of 3 autos, but was wondering what the best and safest height from the top of my plants the lights should be positioned. I run a 18/6 light schedule if that matters. Also using soil. I don't wanna chance frying or killing my girls. PLZ HELP...thnx

 

[Densenug]

I run my 300w Mars normally about 14-18" above canopy in flower. early veg/seedling start at 24" and work your way down 1-2" at a time every few days. Keep an eye up top of plants. I have a few as close 11-12", check out my grow journal you will see them in action, I run 6 of the 300w mars and a few others.

 

[Densenug]

And Welcome to

 

[johnw2269]

Thnx man that's what I needed to hear. It's awesome you actually use the same light too. Thnx again, I'm gonna check out your journal rite now.

 

[johnw2269]

Your journal grow looks real good. So 14 to 18 inch for flower and start at 24 inch for seedlings?

 

[Densenug]

Yelp that works good for me and I get best growth if I keep my lights on temp in the low 80s, you need anything, stop by my journal.

 

[Mars Hydro]

Hi John, here is our recommend hanging distance.
germination 24-30inches above the plants
veg:18-24 inches above the plants
flower:12-18 inches above the plants
Hope it helps.

 

[johnw2269]

Thanks for the info Sara that's good to hear.

 

[yankeetoker]

Hi John, here is our recommend hanging distance.
germination 24-30inches above the plants
veg:18-24 inches above the plants
flower:12-18 inches above the plants
Hope it helps.

Would this be in general for all LED, or for the light that he inquired about?

 

[Mars Hydro]

Hi yankeetoker, it's be in general for LED panel, while it's not fixed. The height is adjustable by the actual response from the plant.

Would this be in general for all LED, or for the light that he inquired about?

 

[johnw2269]

Sarah the lights I have are Mars 300w and I was wondering can I hang them with the long side facing me? Instead of front to back can I run them with the long end facing me and the width on the sides?

 

[Mars Hydro]

Hi John, you can hang them the way as you like.

Sarah the lights I have are Mars 300w and I was wondering can I hang them with the long side facing me? Instead of front to back can I run them with the long end facing me and the width on the sides?

 

[thehitman]

John has good advise.

When I first got my LED light, I had it too close to the plants (flower) and bleached the tops white. Keep an eye on the plants, if they show signs of stress, raise the light a little and monitor the growth.

 

[johnw2269]

Okay well I'm going into week 3 and my plants are small only about a foot to 15 inches tall. They are both autos sugar black rose and northern lights x big bud. Both are supposed to be on the shorter side I believe but I'm just a Lil worried. My lights are about 16 to 14 inches from my canopy I'm just used to having bigger plants at this stage with my old CFL setup. Am I crazy and this is normal with leds or is there a problem? My pH and nutes and Temps are all on point. The growth of both plants as far as business and node spacing is phenomenal but lacking in height. I'm sure they will get a stretch when they hit flowering full on. Please help as I'm debating on switching back to my old lights. Is it normal for plants to be smaller in height when using leds?

 

[OttawaGreen]

I would make them a lot closer. If it isn't bleaching then it's not too low. If it bleaches then raise it slightly. 8" or less is doable usually. But depends on the light, strain and environment - every situation is different.

Rule that will work for all led lights and situations: make it as close as you can while still covering the space you want, and not bleaching. Need a bigger area raise it (and whole area will get less light per square foot) see bleaching, raise it slightly. Picking an arbitrary number because someone else did will not be optimum.
Another important strategy for maximizing yield with LED is a flat canopy (make plants as flat as they can be) so that the bottom of the plant is not really far from the light. Short wide plants. SCROG works for this, but you can do it without SCROG too as shown in my journals.
Here is a good example from my first journal here, two plants under two 260w panels to make a pound dry:
Two Chocolope Plants Under Two Eshine LED Panels in Hydro

Or my current grow in my sig with the same two panels plus a third panel all three on a light mover and 9 strains going in total - still a flat canopy. Note that this is NOT a SCROG the metal frame is to give me tie down points but nothing tied to them at the moment:

At the request of other members I have started doing a training guide on a tall sativa a few days ago. Follow along and see how to make short fat plants optimized to make best use of the lights.

 

[johnw2269]

Awesome thanks for the info. What is the eshine panel? Is it the new Mars pro series? I have 2 Mars 300w panels over 2 plants, given the strains I mentioned do you think I will get decent yeild? I guess 8 gotta run a full cycle to make an a curate comparison. I just hope the upgrade from 184 actual CFL watts to both Mars 140 actual watt led panels will give me better yeilds. I was doing really well with my homage CFL setup. I was doing 3 plants and yielding about 5 Oz total. I hope it's at least just as good.

 

[johnw2269]

 

[johnw2269]

You think they are ok? 23 days old today.

 

[OttawaGreen]

Eshine is the company eshine systems. They made the overpriced lights for the platinum company such as the p300. These are identical to platinum lights at less than half the price.
Mars hydro stuff is good too, I run one of those in my veg cabinet. If you have 280 real watts then you should be able to do over 8 oz if no problems.

Good luck!

 

[OttawaGreen]

Oh and if each of those plants gets its own light then I would drop the lights quite low since you don't need a large foot print. Maybe go down to 8" and watch for bleach or other stress. If none then lower it more.