Cal Mag Deficiency? Urgent!

My setup:

4x4 grow tent
600 watt mh
plants in 1 gallon buckets
Soil is ocean forest
Age: 3 weeks 5 days old.
Average room temps during day: 75-81 degrees
Ph of water adjusted to 6.2


Problem: Pretty much all of my plants are beginning to yellow between the veins on the leafs as well as develop tanish brown spots around the perimeter of the leafs. I am also getting some clawing on the leafs which I thought could be nitrogen toxicity however they are a lighter green not a dark green. I just transferred into ocean forest soil about a week ago with no problems however just in the past couple days this issue has been appearing across all plants. I checked for any presence of bugs with a microscope and found none. I also tested the runoff ph and it is right around 6.5. What could this issue be and how can i fix it? I am currently not feeding any nutrients due to ocean forest being so nutrient rich.

Cal-mag deficiency possibly. I would foliar feed asap with epsom salts. 1 tablespoon dissolved in a gallon of water. I use a pump up sprayer but isn't necessary. Get some cal-mag and dose it according to the label with your next watering. If I'm right, you should see improvement in a few days.

cindysid said:

Cal-mag deficiency possibly. I would foliar feed asap with epsom salts. 1 tablespoon dissolved in a gallon of water. I use a pump up sprayer but isn't necessary. Get some cal-mag and dose it according to the label with your next watering. If I'm right, you should see improvement in a few days.

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awesome that's what I was figuring as well went ahead and picked up some cal mag earlier today just in case. How many times would you recommend I foliar feed them? I had just watered yesterday and the pots are still really wet so wont be able to water in calmag for another 3-4 days.

I would hit them with it a couple of times and then wait to see if there is improvement. Within 3 days you should see something. I foliar feed ALOT. I alternate between epsom salts, fish emulison, (I know...gross) silica, and distilled water. I do it at least once a week (more often in veg) until about the 5th week of flower and it works for me. I don't get as many "deficiencies" as I used to, and I think it discourages the bugs, especially the silica.

What temperature is your soil and how dry do you let the pots get before you feed them? Just wondering because cold dirt can hold water a little long and over watering can cause certain nutrients to not uptake correctly which in turn could be causing your mag def. Maybe try letting pots get dry to the point where they almost start wilting before you water again. I don't think your plant is starved of mag because the soil is lacking, I have used ocean forest a lot and never needed while plants were as small as yours but you might have just got an unbalance batch of soil. Try foliar feeding as cindysid stated but just let them pots get nice and dry. Cheers and good luck

cindysid said:

I would hit them with it a couple of times and then wait to see if there is improvement. Within 3 days you should see something. I foliar feed ALOT. I alternate between epsom salts, fish emulison, (I know...gross) silica, and distilled water. I do it at least once a week (more often in veg) until about the 5th week of flower and it works for me. I don't get as many "deficiencies" as I used to, and I think it discourages the bugs, especially the silica.

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Thanks so much for the advice sprayed them down a couple times and it looks like the newer growth is deficiency free and the spreading of the discoloration to the other older leafs has slowed dramatically.