Too much Mag? Necrosis between veins

[LostTribe]

I have problems across most of my plants except 2 OG moms that look dark green.

I have seedling mix 80/20 peat/perlite w added 10% castings and a bit of dolomite lime. Feeding Calmag/PBP Grow at ~800ppm/6.5ph(60% full strength). All clones at 2-3 weeks veg. No burned tips but most of my plants are showing magnesium deficiency but rest of leaf is dark green. A bit of purple stems(too much phosphorus?). All in veg under cfls.

I was feeding plain water every other feeding. Don't appear overwatered but not completely drying out to bone dry either.

A few leaves have developed whitish sort of burn between the leaf veins. I haven't run anything in soil in a decade please any advice is great! Thanks!

I will try to post a pic tonight.

I will try to water with RO and test runoff as well.

LT

 

[LostTribe]

Last night I ran 100% to run off with plain RO. I caught the run off from straight RO water through the worst one an Ethos CO Chem rbx3. I got .4ec and 7.1 ph. Here are photos of that plant.

Any ideas are greatly appreciated.

LT

 

[Fixer]

I'm growing in coco and just had what looks the same deficiency. I sorted it with cal mag.

 

[LostTribe]

I'm growing in coco and just had what looks the same deficiency. I sorted it with cal mag.

Greetings Fixer!

I am using CalMag at 5ml/gallon as I do in hydro. How much are you feeding? RO or tap water? Were you not using it before the problem or just increased your dosage?

Thank you!
LT

 

[LostTribe]

I did water once with tap water w PBP Grow last week. Not sure if my tap might be the issue, but I stopped and went with my RO to narrow it down. I have read that some tap water will really mess some plants up and this stuff is 350ppm @700 scale so not sure.

 

[Fixer]

Hi LostTribe, I wasn't using any MgCal, the California Substrates coco I'm using supposedly doesn't need any beyond the GH Flora nutes.


The deficiency showed up on the fastest growing plant so I started using one Tbs/5gal of SensiCal. The leaves that have damage haven't gotten any better but the leaves that looked like they were headed that way look a lot better. I'm using RO water.

 

[Vanilla Phoenix]

I did water once with tap water w PBP Grow last week. Not sure if my tap might be the issue, but I stopped and went with my RO to narrow it down. I have read that some tap water will really mess some plants up and this stuff is 350ppm @700 scale so not sure.

That’s some pretty dirty tap water. Mine comes out at 110ppm.

 

[LostTribe]

That’s some pretty dirty tap water. Mine comes out at 110ppm.

You think I need to spray w epsom? I normally don't spray my plants other than un rooted cuttings or just take it easy on them for a bit.

I had similar issue in veg with my last 2 hydro runs all w RO though. I think I PM'd you on one of the runs.

 

[troutman]

You think I need to spray w epsom? I normally don't spray my plants other than un rooted cuttings or just take it easy on them for a bit.

Epsom salt is fairly soluble and I would just water it. Spraying will leave ugly white residue.

 

[LostTribe]

Epsom salt is fairly soluble and I would just water it. Spraying will leave ugly white residue.

Never watered with it. Sprayed at 1 tsp/gallon last run but didn't see improvement. Recommended watering dosage in RO? Shall I ph as well?

 

[LostTribe]

I did not apply any epsom. I feel like this is directly related to the watering with my tap water plus PBP. Everything was doing great until last week. I wouldn't doubt it if there was something toxic in my tap water as well at 350ppm who knows what kind of crap could be in there.

I watered again today with pure RO and want them to dry out good before I water again. Probably do 1/2 strength nutes in RO. If shit gets worse I am gonna have my plugs on standby and get them back into my hydroton ebb table. Hoping they are going to be fine though.

I am betting it was lockout.

 

[DrDee]

Hi Lost Tribe,
I'm going to offer an alternative theory. The green on the leaves is very dark. I'm thinking that you are giving too much nutrients, and specifically too much N. Nitrogen in excess can negatively effect K absorption.


I think it's a K deficiency caused by nute excess.


Also you said you watered in between with water. Straight RO water will wash out your calmag buffering. Always put at least 1/4 strength nutes or some calmag...or even your tap water would be better then RO.
Thats all,
JD

 

[SamsonsRiddle]

I agree with the guy above about the over fertilization.

 

[LostTribe]

Hi Lost Tribe,
I'm going to offer an alternative theory. The green on the leaves is very dark. I'm thinking that you are giving too much nutrients, and specifically too much N. Nitrogen in excess can negatively effect K absorption.


I think it's a K deficiency caused by nute excess.


Also you said you watered in between with water. Straight RO water will wash out your calmag buffering. Always put at least 1/4 strength nutes or some calmag...or even your tap water would be better then RO.
Thats all,
JD

What up Doc?

I agree that they are too green. My Tahoe and Biker are even darker but no mag issue. The OG's have dark purple stems now.

So even flushing soil I need to add Calmag if its RO water? Never heard of that. I was feeding just water the last 2 days. I also have castings and a bit of powdered dolomite lime in the mix.

They are too dark though so I shall have a look at N toxicity.

 

[f-e]

Mg or K. I'm actually going with Mg, as the signs are stronger towards the base of the leaf than the tip. Both push the other out. Might be some Ca just showing, which completes the circle. Add the dark green, and the case for over feeding is difficult to argue with.

Rinsing them out to 0.4 with RO will cause problems. That is surely deficient of most things. They won't get better like that.

 

[G.O. Joe]

If the runoff is over 7 in peat and only 200 ppm, overfert is not the problem. If your lime is powdered I'm guessing it's hydrated lime - calcium hydroxide - not calcium carbonate limestone. You'd want runoff to be about 5.8 and 300-400 ppm at this point. With small chunks of limestone like promix has, not powdered hydrated lime. My tap sucks too it's 370 ppm and 8.5 pH, it's only fit for mixing with phosphoric acid to initially condition rockwool.

 

[Nifty_PoT]

I also had major Mg issues for a while with the colorado chem,especially when they are under white LED. These plants are the most Mg hungry plants i have ever had lol
Also as DrDee said never water with straight RO water , Mix your Tap and RO til you get about 100ppm then add your nutrients to that ,this will be much better than just RO. When you use cal mag to buffer the water you get an excess of Nitrogen because the cal mag comes with a bunch of nitrates.

 

[DrDee]

What up Doc?

I agree that they are too green. My Tahoe and Biker are even darker but no mag issue. The OG's have dark purple stems now.

So even flushing soil I need to add Calmag if its RO water? Never heard of that. I was feeding just water the last 2 days. I also have castings and a bit of powdered dolomite lime in the mix.

They are too dark though so I shall have a look at N toxicity.

Hi Lt,
Sorry about that...that's advice for coco...not soil. Got mixed up a bit. Water is fine.


Fairly common to overdo it with really strong organic soils and then any feedings just add to it. Seems to me, you're on the right track. Just water for awhole to let plant use up some of those nutes. I [personally don't like to flush soil. I grow in coco.
Cheers,
JD

 

[LostTribe]

If the runoff is over 7 in peat and only 200 ppm, overfert is not the problem. If your lime is powdered I'm guessing it's hydrated lime - calcium hydroxide - not calcium carbonate limestone. You'd want runoff to be about 5.8 and 300-400 ppm at this point. With small chunks of limestone like promix has, not powdered hydrated lime. My tap sucks too it's 370 ppm and 8.5 pH, it's only fit for mixing with phosphoric acid to initially condition rockwool.

That runoff was after 200% runoff from straight RO water.

I used hi-yeild brand ag limestone. Says its derived from limestone, dolomite lime.

This is black gold seedling starter mix plus some perlite and a bit of the ag lime, which is powdered.

Still pretty wet so I am waiting for them to dry to see if new growth is being affected but read that older leaves will be affected if its Mg and the new leaves pull Mg from older leaves. Does K do this as well? Those tiny white dots are also present but very tiny and only on a couple leaves.

Solo cups are also starting to get root bound but I am not getting lower leaf yellowing?

At this point ~3 weeks from rooting what the max ppm/ec I should be feeding in soil/soiless and how often?

Thinking back I am pretty sure I was overfeeding the hydro plants too. Eventually tips burned. Don't have tip burn as of right now on these soil plants.

Thank you everyone!
LT

 

[DrDee]

LT,
Feeding strength depends on strain and pheno even...but I feed my clones that age at 500 to 600ppm. Growing nute hungry indicas at the moment.


And soil growers should allow drying and maybe just water in between. Like feed...water water...repeat Or some guys alternate feed and water.
JD