Cal & Mag

[MindSoup]

@DeltaMelter thats definitely shed some light thanks. I do get full analysis reports updated every 3 months from the local water board, or do you mean so I know my total PPM ? Do you think I could request that from them?

 

@ratdog yeah unfortunately they're gone so that's the best I can do, your pictures look like what I had but a bit worse. 

[DeltaMelter]

Just now, bill cooper said:

It would show both mg and cal in that case, IMO.

Not necessarily as Calcium is used more in new cell growth so it shows quicker, even in veg - but an Mg deficiency might not show until flower when the plants demand much more Mg but need less (very little) Ca.

 

The Mg might not be so low as to be deficient but it can bugger up the ratio and stall uptake.

[DeltaMelter]

@MindSoup I found my local water readings didn't show the data I needed so I paid for a water test from Growers Ark (£30) - they were even kind enough to do the maths so I can work out how much Mono Ca to add to bring my ratio up to 3:1.

[ratdog]

Just now, MindSoup said:

your pictures look like what I had but a bit worse. 

 

 

this is exactly how it goes every time, not all plants as some are less hungry for cal, and that is a stock image, but it could easily be one of my plants from a couple of years ago.

[HazyDaze]

Ooh @GSZZ  not like you to be that touchy, usually. 

 

 

 

 

[GSZZ]

Just now, DeltaMelter said:

As fucked up as it seems low levels of Mg can stop Ca uptake even without a direct Mg deficiency showing.

 

How far down the rabbit hole are you gonna go with that one? Nutrient uptake in ratio to other nutrients is a bit like a domino effect, look at leibigs law of the minimum, Is it actually an excess or deficiency? Its easy to say he's not got enough Mg, but when transpiration is getting pulled from the extreme to the not so extreme, and we don't even know what pot temps or leaf surface temps are, we don't actually know whats causing the problem.

 

If an environmental issue is causing the plant to uptake loads of Ca and it causes an Mg deficiency, is it because theres not enough Mg or because the environments wrong?

 

@MindSoup please accept my apology I am sure you can appreciate why I thought you were being a smart twat with me not that its an excuse for that kind of behaviour, I'm the first usually to get the wrong end of the stick when I can't convey tone, especially when you've got the mod badge under your name its as though people start taking your advice like its some sort of challenge to prove you wrong. Makes you not want to help ya know what I mean?

[GSZZ]

Just now, HazyDaze said:

Ooh @GSZZ  not like you to be that touchy, usually. 

 

 

 

 

 

One of them days hazy its not @MindSoups fault its mine for being a mardy bastard with monk on !

[MindSoup]

Well it seems there's some mixed opinions on this subject . it's hard to know what to do. I'll take a few close ups of my Lemon Drizzle tonight as from what that thread was saying she's starting to show the early signs of deficiency. I'm leaning towards just balancing out my water so I feel like I'm trying something at least, if the problems happen again I'll have to consider something else. 

 

@GSZZ all good mate, we're all friends here. And thanks for that input we got there in the end.

 

I did measure my soil temps for a while and they where consistently about 2° lower than air temps, didn't bother putting them down as I thought that was the general rule of thumb.

 

As for humidity I've literally been told in the past not to worry unless it gets too high , so never really thought much of it, but regardless as I said I have no way of control it other than my fan ramping up above 65% would the fact that the other plants (different strains) didn't get this issue shed any light on possible causes?  

 

I really do try and keep things simple/low tek tbh coming from a lifetime of outdoor growing and landscaping the idea of recording leaf temps just seems way too in depth for me tbh, but I will do whatever I need/am able to if it  keep my ladies happy.

 

@ratdog @DeltaMelter my report has a lot of info on it, just not a total ppm, I'm sure I could add it all up mind. What specific things do I need to know from it and I'll have a look, I wish I could post a screen shot but it's a potential security risk.

Edited August 24, 2021 by MindSoup

[ratdog]

Just now, MindSoup said:

What specific things do I need to know from it and I'll have a look

 

 

not sure what you are asking mate, i'm just saying that that is what cal def looks like if untreated

[MindSoup]

@ratdog sorry it was actually @DeltaMelter I meant to tag. 

[GSZZ]

Just now, MindSoup said:

recording leaf temps just seems way too in depth for me tbh,

 

I feel you on this mate, but unfortunately when you're growing in an artificial environment within another environment things like leaf temps are really important, if its too low or too high you're going to have a really bad time. If its too low and your light intensity is too high, you start getting these issues like what you're seeing - alot of growers think its because the light is too intense so turn down the light and the plants look better - they've suited the intensity to the environment, not the environment to the intensity - you could actually be the other way around, I think you mentioned you were using 180w of LED in that space of yours? Maybe that is a little too much? I'm spit balling here.

 

I hear, read and talk about these kinds of problems everyday online and in the shop. Apart from maybe @ratdog (dont you still get the problem though?) I've never known anyone have a cal/mg def due to an actual lack of either element.

 

Just now, MindSoup said:

As for humidity I've literally been told in the past not to worry unless it gets too high

 

if commercial glasshouse agriculture is anything to go by (and I like to think it is) you ought to be keeping your RH around 75% to keep the stomata open so there is a constant draw of water from the root zone and a constant flow of nutrients, and ultimately a constant flow of growth. In real world applications like ours where it is difficuilt to keep air temps, leaf temps, relative humidity and absolute humidity all within acceptable ranges, running a room at 75% constant is asking for it.

 

Anyway the point im making here is, if you let your humidity get too low the stomata closes and photosynthesis stops, the flow of nutrients and water stops, and you start getting nutrient uptake issues a bit like what you're seeing.

 

[DeltaMelter]

@GSZZ I know right? That rabbit hole would have been a mile deep for me if I hadn't had the water tested and ratios checked as mine is close to 1:1 - I'm in the 1% and chased a bunch of other environmental variables until I checked the obvious one - water. I'm not saying he hasn't got enough Mg - just that the ratio needs to be balanced for uptake. I think we are arguing at cross purposes here. I was simply arguing that a poor ratio of the two is a problem and that they affect each other both when scarce and in excess.

 

I'm aware of Liebigs law of the minimum but this is a simple ratio of Ca to Mg for optimal uptake so its simply ONE of those environmental factors to be eliminated as a problem just like low RH or cold rootzone temps. I appreciate you don't think its a priority vs other factors though because for most folks it's usually something else.

 

@MindSoup You can buy an IR thermometer for about £15 which will give you your leaf temps in a jiffy. Then you should have a much better idea of your overall environment and can even map to VPD if you like being a proper nerd. Also, low humidity can cause transpiration stress and lead to problems with the uptake of Ca and deficiencies there which I'm assuming is what @GSZZ is alluding to so if that swings around a lot then that could be the issue right there.

Edited August 24, 2021 by DeltaMelter
Jesus Christ my spelling ffs

[growinggold]

Fuck it is I'm buying a ir thermometer and pizza stone they've been on list for months now.

 

Let get to bottom of this. 

[EarLobe]

3 minutes ago, GSZZ said:

Anyway the point im making here is, if you let your humidity get too low the stomata closes and photosynthesis stops, the flow of nutrients and water stops, and you start getting nutrient uptake issues a bit like what you're seeing.

Wasn't there a thread somewhere discussing this exactly? A problem with nutrients burning in the leaves due to the stomata closing up.

 

This topic is a mine field...

[MindSoup]

I think we're getting somewhere. 180 watts is fairly high for sure, so it could be part of the problem, and although your saying I'd be better to match the environment to the intensity that doesn't seem possible, so maybe my easiest/cheapest option is just to raise it higher/turn it down. 2 niggles here though, the plant's that got the issues where the shortest, but also a different strain so I'll forget about that for now. 2nd 30cms below the light is still a lower lux/par than the sun was this morning, again this could still be too high for all I know. 

 

So humidity, your saying aim for 75% or don't? I'm not quite clear on the wording. I guess I could get a little mister or something to keep it getting too low, what % would be too low? 

 

I will get a thermometer and have a look at leaf temps, I'm guessing 25-28° is what I'm after? 

 

It's weird how plants thrive outdoors with such wild fluctuations, I guess root mass would help in a way but what about the ones in pots ??? Probably not worth getting in a muddle over but too late .