Anybody know this deficiency?

AMgrowing

Member
These are auto plants in their 4th week. Starting to flower. They starting showing these signs about a week ago. The leaves are getting yellow and brown spots, drying up, and turning crispy. It started on the bottom leaves but now it's moving up to the top. Really trying to fix this so I don't hurt the plants yield. Anyone know what this could be?
 

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OldMedUser

Well-Known Member
See this all the time.

Toxic salts buildup. TSB.

Causes are too low RH which causes the plants to transpire much more water than they should and bring in more nutes than they can process which gets stored in the leaves until there is so much salt in them they dehydrate and burn up going hard, thick and crispy dry.

To many nutes in hot soils or overfeeding cause this buildup and hard tap water also contributes it's minerals to make it all even worse.

I've had the same problem for years and finally clued in to what was going on about a year ago. VPD or Vapour Pressure Deficit is when your humidity is too low and brings this condition on. With my last grow of around 27 plants growing in a 50:50 mix of soilless and potting soil got fed at half the normal rate I'd use and I got all the way to the end of the grow with fan leaves yellowing and remaining soft and pliable. No sign of the dreaded TSB.

VapourPressureDeficitChart.jpg

I will now apply the same trick to some DWC tubs soon to be started and see how that goes but expect good results. Too hard for me to keep the RH at the proper levels so lower nute levels should do it. It's not like the plants will go hungry as along with the extra water they will consume they will also be drawing in more nutes. Finding that balance will be the trick.

I'd flush well if I were you and for the final flush add 1/4 strength flowering nutes to finish those girls off with. Leaves already affected will not recover and you'll likely see more leaves die off as the flushing will not remove salts from the leaves already loaded up with salt. At least you shouldn't see it in the bud leaves at the end tho you may see a bit of that.

Do nothing and expect pot that snaps, crackles, and pops like a bowl of Rice Krispies when you smoke it.

Good luck eh!

:peace:

PS:

I found a great spot to download FREE POT BOOKS. I downloaded a grow bible first and got lots more. Books look great and complete like the real ones I have here. No web site but just a page of links. Just right click on what you want and then "Save Link As" to download so they don't open first as some are 50+ megs. They got lots. Enjoy.
 

Tom Tucker 313

Active Member
Flush with 7.0 ph h2o and add spray and grow to your nute regiment.

start very slow with 5ml per gal with 6.4 h2o

Always monitor ph levels before and after applying nutes. drastic or sudden changes in ph can cause shock or stress which leads to lockout of particular nutes. causing a wide variety of problems
 

MarWan

Well-Known Member
PS:

I found a great spot to download FREE POT BOOKS. I downloaded a grow bible first and got lots more. Books look great and complete like the real ones I have here. No web site but just a page of links. Just right click on what you want and then "Save Link As" to download so they don't open first as some are 50+ megs. They got lots. Enjoy.
Thanks for sharing ;), lots of books and media.

 
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