Magnesium issue?

I am on week 5 and 3 of late flowering and my plants are turning yellow and showing brown spots. I looked up the diagnosis for my plants and it seems to be a magnesium problem so in order to fix it I have been doubling the amount of cal-mag. But it seems to be either locking out the plant or causing nuts burn. I read some where that epson salt is something that can be used to fix this problem but I am not sure how much to use or if this is truly a magnesium issue.



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It looks like a mobile nutrient issue (new growth is good, deficiency showing on old growth). This could be Mg deficiency. (Ca is immobile)

If you have Cal Mag you can mix a spray. I haven’t done it in flower but in veg I spray/drench mine and let them dry away from the grow light so it doesn’t burn them.

As far as Epsom Salt, I have used a tsp with Recharge mix in a quart of dechlorinated pH-ed tap water.


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How do I de chlorinate the tap water and ok so put it in a spray bottle and just spray it only the leaves

Just let it sit out ~24 hrs and it will off gas the chlorine

Fill a gallon jug from the tap. Give it a good shake with the lid on and then take the top off for a day. Chorine gone.

I think you can also distill water. Boil water with a empty pot in a pot of water with the lid upside down on the main pot. Slow process but quicker than 24 hours. Putting ice in the lid speeds it up a little. There are videos of this on the tube etc. You could also just boil but I think it doesnt get all the additives out of tap water.

Should I do this with every feed and watering

I mixed calmag and neem oil cause there is a nat problem to but how much cal mag should I put in for a 20 ounce spray bottle

I am new here so not sure about the amounts. Everything Ive read says to let the water sit for at least 24hrs or more to remove the bad additives when using tap water. In a pinch I know you can distill rather than wait.

My Cal Mag says 1 tsp per gallon then adjust pH for a spray. I’d mix 32 oz (Qt) with 1/4 tsp Cal Mag, adjust pH, then fill the 20 oz bottle.

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You should always dechlorinate your tap water before using on your plants

One other thought: Some municipalities may use chloramine vs chlorine. Chlorine off gases by itself chloramine doesn’t. Using a granular activated carbon (GAC) filtration system is the most effective way to remove chloramines from water