Mag problem, then Cal problem, I think

[eggzin]

Hi guys,

I'm running RDWC, city water @ 8.0 ph and 90 ppm's. I use Ph Down to adjust to 5.8.

At a certain point, around 2 weeks from seedling, I started to notice what clearly looked like a magnesium deficiency and it was steadily getting worse. I had no Cal/Mag so I researched using Epsom Salts.

Based on a post by Tokin Roll, I added 4 tablespoons to my 4.5 gallon resevoir. He'd said it was hard to overdose on Magnesium. After adding that, the ppm's were 1,100 and change. 24 hours later, the problem was much worse. I bailed out the resevoir, and refilled with a much lower dose. After that, the plant was looking even worse. Now I was getting large numbers of brown spots and some droopy leaves. It seemed I now had a calcium deficiency.

I've just finished flushing the plant for 2 days. The first day the ingoing water was 90 ppm--after 24 hours the ppm was 140 ppm. I flushed again--ingoing water at 90 ppm, at the 24th hour the reading was 100 ppm. It seemed that the plant had flushed itself out.

Last night, after the 2 days of flush, I refilled using my usual dose of Flora Nova Bloom at 300 ppm, and 5.8 ph. I'm waiting to see what the results are. I'm ordering some Cal/Mag today.

What the heck happened? Did I overdose with Epsom Salts? Did the magnesium cause the calcium to get locked out? Any thoughts on why the problem began in the first place? I've had 5 very successful grows using Flora Nova Bloom, start to finish. I should mention my water is different now--I'm in a different house.

Any thoughts? I would appreciate them.

 

[bluter]

it's hungry. does look like it wants cal-mag among other things.

are you on RO or tap. RO is best for dwc, it gives you a blank canvas to work with. if your water changed so did how all your nutes balance out. could be the root of the problem. i don't think you locked out.

 

[eggzin]

it's hungry. does look like it wants cal-mag among other things.

are you on RO or tap. RO is best for dwc, it gives you a blank canvas to work with. if your water changed so did how all your nutes balance out. could be the root of the problem. i don't think you locked out.

I don't know what you mean by this...?

As I said in the first paragraph, "I'm running RDWC, city water @ 8.0 ph and 90 ppm's. I use Ph Down to adjust to 5.8."

What makes you think I didn't lock out?

 

[Listersmeghead]

Hi eggzin.
I noticed you mentioned using flora bloom all the way through, so you don't use the grow formula? It may be that this strain needs a little extra that's in the grow nutrients.
When I was doing hydro I'd have the feed a little stronger by now ( but that's my own personal opinion)

Lastly, what do the roots look like?

 

[eggzin]

Hi eggzin.
I noticed you mentioned using flora bloom all the way through, so you don't use the grow formula? It may be that this strain needs a little extra that's in the grow nutrients.
When I was doing hydro I'd have the feed a little stronger by now ( but that's my own personal opinion)

Lastly, what do the roots look like?

Hey Listers, thanks. This is the last seed of the purchase I made 5 years ago, same strain as my other grows. It did have a hard time getting off the ground. The tap root got all twisted, but I was able to save it.

The roots look okay. A little brown, but that's from the nutrient. Not slimey. But a couple pieces came off when I slid my fingers down to check for slime.

Resevoir temps haven't been over 70 deg. But I'm about to drop in some Hydroguard.

 

[Weaselcracker]

At 4 tablespoons of Epsom salt in your reservoir that’s six times the typical level of magnesium.
Magnesium toxicity is rare, I don’t think it’s impossible though.
Once leaves get frazzled by deficiencies or toxicity it becomes extremely hard to judge any symptoms at all. You pretty much just have to go with safe best practises at that point and hope it doesn’t get worse.

 

[eggzin]

At 4 tablespoons of Epsom salt in your reservoir that’s six times the typical level of magnesium.
Magnesium toxicity is rare, I don’t think it’s impossible though.
Once leaves get frazzled by deficiencies or toxicity it becomes extremely hard to judge any symptoms at all. You pretty much just have to go with safe best practises at that point and hope it doesn’t get worse.

Thank you WC. That 4 tablespoons seemed to be a lot to me at the time, but Tokin Roll seemed to know what he was talking about--he had a whole write up about using Epsom Salts...

A very good point about the leaves getting so frazzled that it's hard to tell what else may be happening. What that says to me is that, although I am quite sure the leaves were showing a Mg deficiency, it may not have caused (or I might not have been able to correctly diagnose) a calcium deficiency.

It's now a waiting game to see if my corrected nutrient plan will work while I wait for the Cal/Mag to arrive.

Thanks very much.

 

[Weaselcracker]

I am no expert on well water because I use rainwater but your plants should have been getting some level of calcium at 90ppm -just probably not enough.

2.5 grams per gallon of Epsom salts should provide more than enough Mg. That’s assuming no other additional sources. Usually ES weighs reasonably close to 1 g/mL if you don’t have a scale though.

Chasing deficiencies is usually about the same as chasing wild geese only less fun...

 

[eggzin]

Yes, much less fun. I prefer set it and forget it.

Thanks for the dosage tip. I do have a scale.

 

[bluter]

I don't know what you mean by this...?

As I said in the first paragraph, "I'm running RDWC, city water @ 8.0 ph and 90 ppm's. I use Ph Down to adjust to 5.8."

What makes you think I didn't lock out?

it means we don't know what's in your water. you're not on RO, and we have no idea what the base ppm of your water is, and what the mineral content of what that ppm would be. Tap and unfiltered water usually has a higher calcium count, as well as other stuff in it.

if you're down around 120ppm or under for a base it may not have so much effect. if over things can get dicey.

 

[eggzin]

Bluter, sir, you just quoted me saying the city water I'm on is 90 ppm at 8 ph. I've said it twice. I don't know what's in the water unless I have it tested. Not many people growing here have their water tested.

Unless there's something brutal in the water it should be good. That's why I asked what you meant.

 

[bluter]

Bluter, sir, you just quoted me saying the city water I'm on is 90 ppm at 8 ph. I've said it twice. I don't know what's in the water unless I have it tested. Not many people growing here have their water tested.

Unless there's something brutal in the water it should be good. That's why I asked what you meant.

sorry i thought i'd read you'd recently changed water sources.
that's where most of my posts were coming from. thought it was factor in the issue.

 

[eggzin]

I understand Bluter. Thanks for your comments. Sorry about the confusion.

 

[eggzin]

At the advise of Weaslecracker, I added a more informed dose of epsom salts a week ago while I waited for the CalMag to arrive. I added the calmag 2 days ago. I also bumped up the Flora Nova Bloom. I'm now at 700 ppm.

The difference between last Sunday and today (Saturday) is quite stark. The foliage has become lush and green. You can see the damaged leaves under and through the canopy.

In hindsight, I think all my grows have had somewhat of a magnesium deficiency I just didn't recognize it -- largely because it hadn't gotten this bad before. This time I saw the same type of yellowing as before, but it progressed to a more recognizable state. This is possibly the result of the lower ppm out of my current tap water compared to my tap water at the other house.

Anyway, I'm back on track and looking forward to building up this plant before I switch to 12/12.

Thank you for the help you guys.

 

[bluter]

nice turn around. good job.

 

[Obi Wan]

Kudos

 

[eggzin]

nice turn around. good job.

Thanks Bluter. I appreciate that.