is this a magnesium issue?

[puck07]

Hello all you good people

I'm about 3 1/2 weeks into flower and I have some concerns that I would like to address, hoping some of you could chime in and lend some help.

Been growing for about 4 years, had some good runs and some bad ones. Still learning things all the time, far from perfect..

I am doing C-4 and Super Lemon Haze. My Lemon Haze plants are starting to show some yellowish/brown some might say rusty colored spots/tips on the lower leaves. I suspect magnesium but can't say exactly.

Fox Farm Ocean Forest, PH of water going in is 6.3-6.6, runoff reads right at 6.5. I transplanted them into fresh soil one week into flower. I am using AN grow micro bloom on half the plants and trying out GH Floranova bloom for the first time on the other half. Don't really see a whole lot of variance in spotting leaves for either of the nutes, pretty similar.

Since I transplanted into fresh soil I was not immediately feeding as ffof has plenty of nutes for about 2 weeks of steady healthy growth. All plants have been fed one time at 500 ppm, I generally water with plain RO water, but have watered 2 times with 150 ppm of Cal Mag.

Do i need to bump up the Cal Mag? I know some will say that 500ppm is too low but my last run I started with about 850 on recommendation from a friend, that did not turn out so well. Immediately burned my plants(chiesel) and started having lots of problems. Checked my runoff after 2 feedings of 850 and my ppms were over 2000. come to find out ffof will give a reading of 2000ppm straight out of the bag and will be similar to that at 2-3 weeks of flower with no extra nutes.. Thanks a lot for any advice and feel free to ask for any more info

ps My plants other than a few lower/older leaves spotting look fantastic, I want them to continue on a healthy path

 

[originalogrower]

Can you put a picture of whole plant. So I can see upper and lower leaves but does look like some sort of mag issue.

 

[puck07]

sorry the one pic is blurry, I think you get the idea from the pics of just the affected leaves that I cut off, just wanted to show the very bottom of the plant where the problem is at...

I know you'll notice some minor yellowing of tips, which I assume is just a slight nute burn. Which is sort of confusing considering I've only fed nutes one time at only 500 ppm 2+ weeks into flower and my buddy grows this same strain and is feeding 800-1000 ppms in coco, and he feeds almost every time he waters(not full strength) but still, and I get burn after one feeding??

 

[originalogrower]

It's looking like mute burn. I would recommend flushing with water only to prevent lockout. Then continuing nutes after noticing difference in upper leaves. Once leaves are gone there is no bringing them back. I will keep an eye out if you keep me updated I will help where i can.

 

[Baltazhar]

Hi

Whats the size of the container ? How often , and how much do you water them?

To me it's look like you did'nt water them enought , but i might be wrong

 

[Hydro-Soil]

Definitely not Magnesium.

Overfed for sure, Coco doesn't have any nutrients in it, Foxfarm Ocean Forest does.

Back to plain water and things should recover.

Stay Safe!

 

[420MAN78]

That's not a Mag problem IMO. Looks more like a Cal/ph prob or over feeding like others have said. Lots of times when problems show up on the leaves it's becasue the ph isn't right and you get lockouts.

 

[SeaMaiden]

Agree w/the others, not Mg, but if the spots are showing up on older growth where there is already newer growth, that disallows Ca. I'm leaning towards a K+, slight.

 

[shredGnar]

Hi

Whats the size of the container ? How often , and how much do you water them?

To me it's look like you did'nt water them enought , but i might be wrong

Also would like to know this, I know with coco if it is let dry out completely it can cause salt (Nutrient) levels to rise in the medium leading to all kinds of lock outs.

 

[puck07]

Thanks everyone

I'm in 2 gallon pots and I water every 3-4 days with about 24 oz of water or 710ml. I'm using a 12 oz dixie cup to measure my water with, so I give them 2 of those cups of water.

I water when the top 2 inches or so of the dirt is dry, stick my finger in and test...

They've only been fed once. I was planning on doing feed, water, and then a second water(rinse) with some runoff to check ph and ppms.

When you say just to give them plain water for a few times, is that RO water or should I still supplement some cal mag, or save the cal mag supplementing only to feeding time?

Is there a reason why the oldest fan leaves at the bottom would be showing the most burn? I thought that was a sign of the plant pulling stored nutes...

 

[puck07]

Hi

Whats the size of the container ? How often , and how much do you water them?

To me it's look like you did'nt water them enought , but i might be wrong

curious, what would make you thing it is an underwatering situation?

 

[puck07]

curious, what would make you thing it is an underwatering situation?

*think

 

[originalogrower]

At the moment do not supplement with anytging straight water will be fine if you have ro water that will be good. But no nutes for a little bit to leech salt from roots but plants will be fine soon.

 

[Baltazhar]

Plants has adaptive metabolism ( cannabis at least).

In low water/ high nutrient environnement (simulated by not watering enough) , plants will devellop woody , rather thin stems.

In high water/low to high nutrients , they will devellop thick hollow stem to handle water.

You want your medium to be fairly dry after a transplant ,i t help quick roots devellopement , but in small container , once they are settled , you doesn't want them to dry as that was the case early on.

10% of the container volume every 3 or 4 day seems to be low , it's enough to sustain growth and bloom but not enough to get optimal results.

Go to 15% and see if something change (water till few drop of water come to the end)

 

[originalogrower]

How are the plants coming.

 

[puck07]

Thanks Baltazhar. You are right, I was going a little bit light on the watering the first few weeks, didn't want to overdue it and leach out nutes from my soil. I have started to water till I get about 20% runoff now that I have fed as to not get any salt buildup.

Thanks original grower for checking back on the progress. So my Super Lemon Haze are looking good, I've only given RO water and have watered a little bit more to get some runoff..

 

[puck07]

but...... Now, right on time I am starting to see some issues with my other strain which is C4. Never ends huh...

Seeing some curling or twisting of the leaves, and some of the leaves about an inch from the tip look sort of scrunched up. If you flip the leave over and look at the underside the vein looks like its shorter than the actual leave so the vein kind of scrunches up the tip, make sense? should be able to see in the pics. There is some tips that are a little orangish so I suspect some minor nute burn, they've been watered with just RO lately, I fed them their first time about 10 days ago with 450 ppm of Floranova Bloom, maybe now just seeing the full effect of the feeding..

This curling/scrunching I started noticing last night, I watered them 4 nights ago with some good runoff, ph was fine. I'm starting to think I packed my soil a bit too tight this time, it usually settles down about an inch but it didn't this time. If i stick my finger in the bottom of the pot through drainage holes its pretty moist when the top 2 inches is pretty dry. bad drainage? could this curling be a drainage problem? solution?

 

[originalogrower]

https://www.icmag.com/ic/showthread.php?t=11688 this is a very helpful link. Stitch helped me many years ago. I will look at pictures a little better soon.