what is causing this 'rust'?

HydroDawg421 · Jan 12, 2022

Any ideas what this is?

I have 6 White Widow in a sealed grow room, 1k LED @ 12", chiller, rooms temps 80 degrees, top of plants 86-88 degrees, quest dehumidifier, CO2, AN Ph Perfect. I just flipped to 12/12 a day ago after 2+ weeks veg, 4 from seed, room RH is 60%.

Everything in the environment is perfect and I have no other concerns. Just wondering should I worry about this 'rust'?

SofaKingHigh · Jan 12, 2022

It looks like the start of deficiencies to me, maybe mg or ca. Do you use any cal mag or anything? Also the last pic they look a little hungry but maybe just the lighting. What are you growing in ?

GNick55 · Jan 12, 2022

raise the light!

jguit · Jan 12, 2022

what EC are you feeding and whats the ec of your runoff? what's with the tips that look chewed? and yes, raise the light while you're figuring this out.

HydroDawg421 · Jan 12, 2022

I have raised the light. It was probably too close. I also put out some sticky traps. I do have something eating the tips of the plants. Give it a couple of days and I'll have them trapped in the glue strips.

My Ph is 6.2 and I don't drain to waste. It drains back into the reservoir.

jguit · Jan 12, 2022

Never tried recirculating coco but what fertilizer are you using and what is your starting EC? I'd imagine if recirculating low EC feed the coco will eventually strip some of the Ca and Mg but it's just a guess. I had an similar issue feeding low EC w/ DTW coco. Once i reset the coco and fed a little heavier, luckily my Ca/Mg issues didn't progress. My plants were showing slow growth and minor Ca/Mg deficiencies. Not as obvious a problems yours are showing.

HydroDawg421 · Jan 13, 2022

jguit said:
Never tried recirculating coco but what fertilizer are you using and what is your starting EC? I'd imagine if recirculating low EC feed the coco will eventually strip some of the Ca and Mg but it's just a guess. I had an similar issue feeding low EC w/ DTW coco. Once i reset the coco and fed a little heavier, luckily my Ca/Mg issues didn't progress. My plants were showing slow growth and minor Ca/Mg deficiencies. Not as obvious a problems yours are showing.

I'm not using coco. I just have a coco mat on the bottom of the flood tray. I'm using air pots with hydroton and top feeding every 3-hours. AN Ph Perfect grow, micro and bloom. EC is currently 2.0. Not sure where it started. I'm using the AN feed chart exactly as it's printed. No nute burn. This WW seems to tolerate a higher PPM.

jguit · Jan 13, 2022

HydroDawg421 said:
I'm not using coco. I just have a coco mat on the bottom of the flood tray. I'm using air pots with hydroton and top feeding every 3-hours. AN Ph Perfect grow, micro and bloom. EC is currently 2.0. Not sure where it started. I'm using the AN feed chart exactly as it's printed. No nute burn. This WW seems to tolerate a higher PPM.

Gotcha. In any case, is your feed draining through your coco mat into your reservoir? If the coco wasn't buffered i'd imagine the same problem would exist to some extent even though you're not growing in it.

Does the EC in your reservoir rise or fall after changing/replenshing the res?

PK1 · Jan 13, 2022

this is the 1st time i've read and heard that the runoff in coco is going back into rez.

HydroDawg421 · Jan 14, 2022

PK1 said:
this is the 1st time i've read and heard that the runoff in coco is going back into rez.

I'm not using coco as a grow media, I'm using hydroton. The coco mat is simply laying in the bottom of the flood table. The table drains back to the reservoir.

HydroDawg421 · Jan 14, 2022

Thanks for all the input. I removed the affected leaves and lowered the light a few days ago. The symptoms have NOT returned. I think I just had the lights too low/too bright.

what is causing this 'rust'?

what is causing this 'rust'?

HydroDawg421

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