Parabolic distance?

**Farmer Geddon** · 26-08-21, 05:54 PM

I've done a lot of scrogs with 600w hps, 1m wide parabolics in 4'x4'/1.2m2.

ime, they can be too low. The sweet spot for me was when the top of the bright band of light on the walls was about 7 or 8 inches above the top of the canopy.

In theory, they lose light because of the design. In practice, infra red doesn't bounce. The lack of IR means that the plants are less likely to overheat. My best yield using a para was 700g/600w.

CHG, I've done a couple of vertical lighting grows. With a 400w hps open plan, no burning at all, they grew into a bowl shape. 1 bud grew 2" under the lamp. A 600w vertical in a tent was a bad idea, the walls constricted them and there was burning. Some of the buds had more crystals on the side opposite the light which I wasn't expecting.

**Krofam** · 27-08-21, 10:42 AM

Originally Posted by CheapHomeGrown

Just found this old post
Attachment 406031

So, I guess you could keep the hood 7" above the canopy

oooh, made an appearance!!

i try and keep as even of a canopy as possible and then let the plants grow up towards the light. i primarily train outwards so dont move my light up much but when i do its only a few inches at a time.
keep an eye on ya ladies. they will tell you if they are getting too much light.

as you are growing with autos, i recommend lifting the pots of your shorter plants when you get uneven canopy instead of topping or training like i do.
bricks come in handy for this.

**Farmer Geddon** · 27-08-21, 12:18 PM

Something I keep meaning to try is to have the light as high as it will go and leave it there. The inverse square law doesn't fully apply to growing. We have reflective walls and much of the light will eventually hit the plants. Or the floor.

There will be a trade off between extra wattage used and convenience. idk what that is though. If the convenience of never having to bother with altering the height of the light only cost say £2 a week extra, I'd be interested.