Phosphorus or Calcium defficiency?

[JamesFarmer]

Hey Everyone,

I started a new grow as follows:

6 x G13 clones
6 x BC Roadkill clones
2 x misc seeds

3 gallon pots w/ Coco

Troph Blumats for watering

Lucas formula (GH Micro & Flora)
5ml/gal CalMag

800ppm
5.8PH

Temps 55-60 night & 75 day
RH 15-25%

1kw MH @ 4'


I received the clones in soil (solo cups) and moved them to Coco. Placed Blumats and did the initial adjustment. They had been in coco w/ blumats for less than two days when I got called out of town on a family emergency. I checked my nute res, AC, lights etc. Said a prayer and left them alone for a week. When I returned home they didn't look TOO bad except for three of them showing the problem pictured below. One is quite bad. The others look like the pic below.

The worst ones looked like they had received more water than the others.

Looking over the trouble shooting info here and other sites it looks similar to examples of phophorus defficiency. I am not certain though as some plants show significant damage and others none. Also, the damage appears to start at the middle of the leaf and move outward. I thought phophorus defficience started showing at the edge of the leaf and moved inward.

What do you all think??

Thanks

James

 

[deacon1503]

P- late stage

 

[OldSSSCGuy]

Have you checked the pH of the run off to be -sure- you don't have a pH problem?

 

[JamesFarmer]

Thank you for your response.

I have not tested the PH of runoff. So far I have not had enough runoff to test easily. Would it make sense to flush with PH'd water and test the runoff from the flush?

Thanks again.

James

 

[JamesFarmer]

Well I researched recommendations for flush & test runoff for coco and followed the direction to:

Add CalMag & Nutes to 300ppm and PH to 5.7 then use this solution to flush. I tested the runoff and found PH 5.6 and TDS 1200ppm.

The PH looks good to me but the TDS seems awfully high.

What do you all think?

 

[JamesFarmer]

P- late stage

Not sure I understand??

 

[SeaMaiden]

Phosphorous deficiency is what he's saying, symbolically. I think I agree.

I don't agree with using run-off parameters for anything, I personally prefer using a slurry method instead. I think you should allow your feeding pH to range, 5.8-6.2. 6.0 tends to be the sweet spot for almost all varieties of cannabis grown in coco, but that's not an absolute.

 

[Gardens Keeper]

I agree with Sea Maiden, check the stems and petioles for redness as well as this is a sign of phosphorous deficiency in plants that do not naturally have those colors as well.

 

[JamesFarmer]

Thanks for the clarification and tips.

I very much appreciate you all sharing your knowlege.

James