Cal-Mag in Soil with RO or Distilled Water

I'm getting the first smidge of rust spots and I'm almost certain it's the beginning of a cal-mag issue.

The directions on the bottle of Cal Mag say 1tsp/gallon. I've done a lot of research and there is really no definitive answer on how much of this stuff to use. I'm on distilled water so I need some supplementation just unsure as to what degree. Tap is not an option.

My thought process was that typical tap has calcium and mag in there and most growers with acceptable tap are putting that level in with every water, so with disitilled water you need to add some every water/feed, ect.

So when I started it was with 1/8 tsp I was pretty sure I was getting a slight deficiency and I folliar fed and bumped to 1/2 tsp. And it was all good for a while. I started getting concerned as the plants got bigger and whether the Cal mag was formulated for tap or RO/distilled type water i.e. if you need more with purified water.

So I've been at about 1/2 to 3/4 tps every water without issue until now and I'm still under the rec dose. But I have the beggining of either not giving the plants enough and slight deficiency or my favorite: too much and slight lockout.

I want to say that the lock out is more likely than not feeding enough or that maybe it just glopped up when combined with the big bloom around the roots. But I am in that fun spot where if choose wrong and give more to correct deficiency and its lockout...i make it worse or... if I don't give it any and make the deficiency worse.

So, the plan was do a light foliar feed to stave off the deficiency and not add any next time to basically put this off and hedge. However, I don't want to be folliar feeding my buds and need to get this figured out.

I figured someone by now would have posted you need this much in this range and with distilled it translates to this many tsp per gallon when watering, but I couldn't find it.

Any thoughts?

70 views...I'll bump it once this morning

I use technaflora magi-cal, it says 1 tsp per gallon of water, then I just water the plants medium as normal.

I use distilled water and I add 1tsp of mag cal every time.

Just follow the directions of the bottle.

Fair enough. Perhaps I'm going too light plus the plants are getting bigger resulting in deficiency. I did a folliar feed to zap it quick and will start increasing to a full tsp.

Thanks guys. Going with the tsp unless I see an issue

What ever happened with this?
My guess is you were going too light, but interested cause i have had the same problem for 3 grows now.

Bottle says use 5ml per gallon, but 5ml per gallon is about 450-500 ppm...which seems high to me. I was under the impression to use 12 of recommended amounts if in not using hydroponics.
I am using Roots Organic coco, and just bumped up to 350 ppm...was using 150ppm and always end up with rust at the end of veg.
Plants look a tiny bit stressed, but rust has stopped.

MrDank007 said:

Thanks guys. Going with the tsp unless I see an issue

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I would assume no news meant good news. cn

MrDank007 said:

I'm getting the first smidge of rust spots and I'm almost certain it's the beginning of a cal-mag issue.

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You're guessing. Brown spots often are a SYMPTOM of too much salts. Could be your food.

My thought process was that typical tap has calcium and mag in there and most growers with acceptable tap are putting that level in with every water, so with disitilled water you need to add some every water/feed, ect.

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And what did your water analysis divulge? You say you don't know what's in your tap water?

I want to say that the lock out is more likely than not feeding enough or that maybe it just glopped up when combined with the big bloom around the roots. But I am in that fun spot where if choose wrong and give more to correct deficiency and its lockout...i make it worse or... if I don't give it any and make the deficiency worse.

Click to expand...

If I had a nickel for every problem associated with bloom foods you guys use which screws up the health of your plants and then the "what's wrong" complaints come filing in.....

Why are you using Big Bloom? What's in it? What is the total element profile your plant "sees". You need to get a handle on those questions.

Edit - another badly hyped product, a watered down, over the top high K food that will insure the decline of your plants and reduced bud production, NOT an increase. 0.01-0.3-0.7

This is (typical) total bullshit! This odorless, liquid fertilizer is a live culture of vitamins, amino acids, natural growth hormones, enzymes, and beneficial organic microbes. Our special, micro-brewed formula incorporates earthworm castings, bat guano and other high test organic ingredients that offer a full, balanced range of nutrients. Norwegian kelp improves nutrient uptake and increases yields. Rock phosphate helps transfer energy from one part of the plant to another, which means bigger buds and more fragrant flowers.

I'm gonna give you some good advice that will not only save you money but do your plants some good. Go down to Walmart and pick up a complete food like a 18-5-9 with micros, or a balanced food like Miracle Gro Tomato Food, 18-18-21 and use it at a rate of about 1 tsp./gal. of rainwater. Peters is another good brand and Vigoro makes good foods....cheap. Add a little epsom salts to those foods as they don't contain any, unless you mixed in a little dolomite lime into your soil.

Now, here's your lock out caused by too much K - http://www.totalgro.com/concepts.htm

Cannabis is a foliage plant not a root crop. Treat it as such. That means it needs good amounts of N until harvest.

Also, don't trust the hype of vendors like Fox. They usually don't get it right and/or think you're savvy enough to understand plant nutrition. But anyone that would sell crap like their Big Bloom ought to be shot.

Good luck,
Uncle Ben