Distance to Plants for CREE CXB3590 (@1650mA, w/ Lenses)

This is not my first grow but I am seeing really weird stuff since I switched from Marshydro 300W to my 4x CXB3590.

Plants have TONS of white/yellow spots which at 1st look like mites but I am 99,99% sure it's no bugs. Plants also feel crumbly dry, and some of the plants simply don't look healthy at all.

I have the lamps anywhere from 11-16" - but could this be too close, especially since I drive them "medium hard" at about 1650mA and I have lenses? I need someone with experience with those same lights for a more or less definite answer.

(Growing in soil, organic, semi outdoors in a greenhouse) Not ALL plants look sick but some do.

I run mine at 20" with 50w to each cob and 80* lenses with no issues. Bring them up a little to around 20" and you'll be good

Watch out for that .01% unsure part and check bottom of fan leaves with loupe or 30 power scope. BORG

First off, what's your RH????????................are you using RO/filtered or tap water??

In my experience, a more powerful light will exacerbate deficiencies that already exist. I added some CXBs to a grow and my cal mag issue got way worse within a day or two.

Take a picture and move the lights up.

Probably some nutritional deficiencies and/or sickness

Since switching to cobs I'm using a ton more cal mag then I did with hps or floro lighting. I light shocked my first run as well even at half power, dry leaves then the cal mag deficiencies. My plants are growing faster with the cobs and healthier now they are getting what they need and are getting use to this much light...

With the exacerbate CalMag issues, there might be something to it. I always had/have CalMag issues (or what it looks like it) at some point in my grows.

Notice I didn't change anything, using the same routine/tap water/nute I did before. The organic nutes I use bring my very hard tap water down to about 6.2. RH is "outside RH" which varies, right now is 60%.

(And yes it LOOKS like mites but I double and triple-checked, also with loupe, underside of leaves etc. And yesterday I sprayed insecticidal soap but I am almost positive it isn't mites. Plants look worse in real life, pics never show properly.)

I don't use lenses or reflectors. I'm running 16 3590's @~ 37w each about 14 inches from the tops. Odd looking. I seem to need more calmag now but the small spots?

@flexy123 what nutrients are you using? Also since the spots are also on the newer growth is the any mist or water droplets on your plants under the lights?

Spots on top growth and old growth. Are there spots on leaves where they are covered by another leaf? If so it isn't light or spray.

Those spots sure look scary to me.

Can you dim the driver?

PerroVerde said:

@flexy123 what nutrients are you using? Also since the spots are also on the newer growth is the any mist or water droplets on your plants under the lights?

Click to expand...

It seems the spots (which look FAR worse in reality than on the pics, by the way) seem to be anywhere, new growth, old growth, backside of plants and leaves which are covered. I didn't mist EXCEPT two days ago because someone suggested mites so I sprayed insecticidal soap. Besides I never had those problems before, also when I misted.

grouch said:

Can you dim the driver?

Click to expand...

Yes I can dim put I'd rather move them away, have them at almost 20" now. It's really like "something" taking out the cholorophyll of the leaves.

My guess, for now, some extreme deficiency brought on (exacerbated) by the new lights because one thing is for sure, since I have the lights the plant grow like crazy. Seeing some yellowing and brown spots I am GUESSING CalMag/Iron.

Do you mix your own soil or is it bag soil? Either way, what's your mix or what's your brand?

It's a "special cannabis potting mix" I get from a garden center here in Spain.

"Professional substrate specially formulated for growing plants with special requirements such as aromatic, culinary and medicinal cannabis. The mixture of peat, coir, compost and perlite brings lightness and aeration to the root system.
It is enriched with organic fertilizer with high levels of iron and amino acids that promotes the development and plant defenses."

It is very similar to mixes like Canna Terra Pro. Light, fluffy, sometimes difficult to water when it dries out because of the peat.

Use more Calmag and beneficials I had the same issue early with my light. The Calmag and availability of nutrients really turned them around. Good luck. Mine looked like yours at the start. Check my journal for recent stuff. Will update today actually

So should I foliar spray them with CalMag? Hesitant to water since I have ovewatering problems and for now would like the pots to dry out. I guess a spray wouldn't hurt...will do that right now.

you may have both mites and nute balance problems