phosphorus deficiency?

Hello folks,

Reaching out for help hoping I can identify the issue with one of my plants. Growing in rockwool ebb and flow. 1 of my 3 plants is showing signs of, what I think is, nutrient deficiency. Top leaves show discoloration where inside the fan leave is a lighter green and outside is dark. Seeing some red / brown rust spots in the middle of the blades and some of them are curling in. Also noticing the tops of petiole's are purple. From what I've been reading I believe this to either be a calcium or phosphorus issue, possibly due to salt build up? Any advise is greatly appreciated

Can you snap a picture without the led on? It's hard to see much of anything in that color lighting.

Yea for sure

How high is your light, and what is you're pH? Also what nutrients are you using?

Light is about 20" above this plant. PH is 5.7 PPM is 1200. Using the Floraseries recirculating with camag, silica, hydrozone and +life mycorrhizal. I keep a 25gl resevoir which feeds 3 plants twice a day. I flushed the rockwool and ran a light feed hoping it'd take care of any lockout but she doesn't seem to be getting better. I can't seem to find a symptom where the inside of the fan leaves turns bright yellow but the outside rim is still dark. The other two plants are healthy as can be using the same lights and nutrients.

lock outs dont get taken care of with more nutrients.
if your nutrient is a complete system, and your ph is spot on, then you are locked up. good luck

Makes sense i figured after flushing i didnt want to leave her bare. Maybe just plain PHd water for a few days and see how she does?

white_rUsSO said:

Makes sense i figured after flushing i didnt want to leave her bare. Maybe just plain PHd water for a few days and see how she does?

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looks p deficient to me. Looks like your in about the end of week two of flower, not a good time to flush your medium for a few days.

What light are you using and what do the roots look like.

If your light was too close you could of cooked your roots and if your feeding 1200 in rockwool and have a 400 watt light then thats to many salts for the plant under that light imo.

Maybe back off on the nutes but dont eliminate them.

Whats hydrozone?

white_rUsSO said:

Makes sense i figured after flushing i didnt want to leave her bare. Maybe just plain PHd water for a few days and see how she does?

Click to expand...

I agree with @Bernie420. There's no need to flush. If your pH is staying stable, you probably just need to dial it back on the nutrients. How have your ec/tds and pH readings been fluctuating in your reservoir?

I can't speak for rockwool at all or ebb and flow, all i can say with regards to nutrients..seems to be a textbook phosphorus deficiency. I'd say 'likely' not due to ph as then other symptoms would appear as well, not just p. The elements that would lock phosphorus out if they were in abundance, would be, zinc, calcium, manganese, iron, or aluminum (that happens at low ph's). If you believe that's not the case, then up the phosphorus, but at the same time, also up the magnesium. That's the element that helps carry phosphorus through the plant and the ratio should be kept near 1:1.

@Bernie420 Right on the money. End of second week when pics were taken. Sitting under a 400w LED.

I'll dial it back a bit and she how she responds. Definitely has gotten worse since pics were taken. Can't see the roots unfortunately its completely scrogged in place but I'm very excited to see what they look like when all is said and done though

Haha apparently, Hydrozoning is the practice of clustering together plants with similar water requirements in an effort to conserve water... Which, of course, is not at all what I meant.. Got rootzone and hydroguard mixed up

@dtl420 PH seems to be fairly stable 5.5 to 5.7. I'll tune it down a bit on the nutrients and see how it goes

@Blitz35 Thats really good info thank you. I very well may have gone a bit overboard with the CaMg thinking it was a calcium defficiency. Still brand new to all of this kinda learning as I go along.Going to dump current reservoir and start new.

I'm guessing the leaves that were affected by all of this won't recover if I figure this out. Should I be pruning them at that point?

Probably fried your roots. Back the nute down to 550ppms and bump up 50 ppms till you get to 750 ppms at peak flower then back it down to 700 and then hold it at 650 ppms till flush. To save on the hydrogaurd product and since your microbes will eventually die in the water can you dip out a gallon of your nuted water and add 2-3 ml of the hydrogaurd and top feed your plants twice a week till the last week before flush . The hydrogaurd is going to bring the roots back. Your light is holding you back from hitting the nutes that hard for flower. You can grow with a 4oo watt flower rig but you have to keep everything in proper balance.

For sure I'll start that up tomorrow. So plant isn't generating enough energy to burn through what's being provided? Makes perfect sense that the feed should match the amount of light provided. @Bernie420 thank you I'll report back in a few days