I give up, what is this deficiency?

[Tynehead Tom]

Those leaves buckling down are your biggest clue. They are buckled, not drooping, which rules out most over the net diagnosis. The flesh is outgrowing the skeleton,essentially.

I had this problem with low available calcium. I had bought some promix and added lime. The lime wasn't solublized and raised the ph higher than expected. Does that mean ph was the problem or a tool to help me solve the problem?

Normally microbes produce the acids to make calcium carbonate available. There's no microbes in promix. I didn't add any acid to my feeds. LEDs make the problem worse, I lost tons of seedlings under LEDs. But hey, now I've got led-proof, low rh proof, high ph proof genetics. I did it on purpose I promise! Got a strain called Newb Dream, straight 2022 future terps! Everybody buy multiple packs for 4/20 stocking stuffers!

Ph doesn't mean anything by itself. You can 'properly' ph RO water all day, doesn't mean you've changed squat. The question is how much acid do I need in my medium. Ph'ing your water is only about the calcium in the water. Lots of crappy organic soils would be better off Ph'ing the water much lower to make up for their lack of microbial metabolites. In all my years I've never even seen growers discuss what microbes produce. Well if you've ever bought citric acid from a store, it was definitely produced by aspergillus niger (black mold).

what you are suggesting , while it reads like good info, I think that only applies to an organic soil , which of course is a "live" soil.
Promix and sunshine mix are devoid of naturally occuring bacteria, enzymes and microbes.
Promix HP has mycos added but otherwise these soiless mixes are sterile from the plant where they are produced.
Adding lime in the OP's situation won't solve the problem. Nor will CalMag or CaliMagic...... Gypsum is the answer as it will not affect PH, it will bind up toxic salts , it will provide essential calcium/sulphur and will loosen compaction and reduce soil surface tension.
When I premix my sunshine mix or when promix hp is all that is availlable in my very small town I add Dolopril (prilled dolomite lime) and Granulated Gypsum.

we can go far down the rabbit hole with this discussion but without the OP's participation as well as the PH , PPM and EC of a runoff sample.... it's all kinda pointless.

Learning and applying Gypsum to my plants instead of calmag supplements and epsom salt flushes/foilars.....has been a game changer.

 

[Wolverine97]

They're massively underfed, in too small containers, with too many plants. Problem compounding on top of problem, this is what you end up with. Give each plant its own root space, or go to full size beds, one of the two. Feed them, from jump, unless you're amending your soil. They're not getting enough Magnesium, which could be locked out by too much K. Also need calcium, often when you increase both but with most being calcium, your Mag issues will resolve, provided other elements are in balance.

If using synthetic nutrients, then you need to maintain your ph level, and monitor it. I run a custom soil mix, and supplement with veganic nutrients, and I don't ph anything, ever. I produce fantastic results, and have for decades that way. But it requires knowing how to read your plants, and respond accordingly, and quickly.

edit: and I agree with Tom above about gypsum. Learn it, use it. I generally use equal amounts of fine dolomite, and prilled gypsum when I mix my soil. Makes a world of difference, but even then, by week four of flower, I need to be feeding at fairly high levels for the next month.

 

[f-e]

I wonder if going into flower meant getting his heater out.

Not logged in for a month. Perhaps found his answer somewhere.

 

[Guest]

I have a plant which demonstrates your problem. I found the pH at the bottom of the pot had risen/fallen to 4.5 which is far too acid.


I flushed and flushed then dissolved Hydrated Lime in water (4tablespoons/10 litres) and poured the 10 litres thru. The plant changed to a healthier colour almost immediately.


I think part of the problem for pH rise/fall was poor drainage. Excess/water soluble nutrients could not get away.


Buy a pH kit. Do what I said or buy some organic Cal/mag which will be micronised Dolomite. Flush through a dose of Lime/CalMag and recheck ph after a day. If insufficient change do again. Remember it will take some hours for the pH to change.

 

[VerdantGreen]

Low soil temps might be the problem if the nutes are there but not being taken up?

 

[Creeperpark]

I second that thought, "That's a cal-mag def if I ever saw one"!