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h0m3b0y started grow question 3 years ago
So... the brown spots in the last 2 photos. Are they Ca deficiency?
Will I do extra damage if I add Ca/mG supplement?
What is the upper concentration of Ca/Mg concentration for cannabis in DWC grow?
How can I tell if I add too much Ca/Mg?

Help please!
My 1st grow
17 weeks
My 1st grow h0m3b0y
Bubba’s Gift
72 comments · 3 years ago
Week 13
Leaves. Other
DissNoof answered grow question 3 years ago
hi there homeboy, first off, daym ! best description i've seen in time out here bro, seriously top marks. You're killing it in every respect. Second : tap water - how are you gonna trust the authorities to tell you what s in your water, same people putting chlorine in there right? That's actually the main problem with tap water : it's got a bunch of chemicals in there that will eventually lead to issues in your plants if you're not careful. So if you're using tap water you can do two things to avoid "cross contamination" or "inter-chemical" lock outs - these are not technical terms by the way, just how i think lol. Take tap water and leave it out for 2 hours or over night - should let the chlorine evaporate. Or use two tablespoons of the cheapest active carbon you can find and just add it to the water, give it a stir, wait an hour. this will remove the chems that might prevent uptake. When you add Cal Mag suplements, again you're correct - can't really be too much, the saturation dose will be indicated on the bottle, and every one of those cal mags are a bit different. One thing they wont tell you is that there is actually plenty of N in those things, so balance that out accordingly. finally a little known fact is that Ca uptake from the roots is efficient at like 20% not much more. Ca uptake by the leaves is 95% so almost perfect. The quickest way to fix the deficiency is to use a foliar spray - just be careful not getting the juice on the buds when you do it - maybe use plastic film to protect the buds. i think the max does for cal mag in the water is like 64 Mg/l but dont quote me on that, that might be the max dose you need for the spray, and I cant find my source again.... hope this helps bro ! :rocket:
OutForReal answered grow question 3 years ago
Hello ! In the total amount of nutrients , so mag should represents 0.3 Ec , I don't remember where I get thus from. Now concerning your plants you have a Calcium def ( or maybe manganese) and the brown spot are a sign , another sign is the dark vein and a lighter colour between and it is also a sign of magnesium def. The brown part in the middle of the plant makes me think about a phosphorous def. I think It's weird to have all that deficiencies signs regarding in your feeding chart :thinking_face:. I hope it will help you :v::skin-tone-3:
HighTV answered grow question 3 years ago
Howdy @H0m3b0y! Plants have 2 types of nutrients called mobile and immobile nutrients. Immobile nutrients CANT be moved around the plant and due to this the symptoms show directly on the newer growth where the deficiency is active. The other type of nutrient is called Mobile. Mobile nutrients can be pulled from the lower leaves to be given to the newer growth up top as a survival method so they show symptoms on the bottom side of the plant first. The type of deficiency you are experiencing is an immobile one. You can really tell this because a lot of mid-growth was effected and the problem didn't start at the bottom of the plant/. Because its your middle leaves that are experiencing chlorosis(yellowing) and early stages of Necrosis(dying) as opposed to old growth or fresh growth this lowers the possibilities quite a bit. The Key here is WHERE the symptoms are showing - a CA deficiency primarily shows on fan leaves that are actively growing and taking in light (its immobile remember) exactly as you are seeing here. That is why I'm confident in confirming you have a CA deficiency. Its recommended to use 1 TSP per gallon of "CalMag" until flower then lower the amount to 1/2 TSP per gallon for flowering. You can see the nutrient levels on all of my DWC grows comparison reasons! You will absolutely want to increase your Ca/Mg as soon as possible for your plants! Hope this helps resolve your questions Homeboy! Feel free to ask anything else :sunglasses:
Stick answered grow question 3 years ago
Hi @h0m3b0y! You are right, it looks like some Calcium deficiency. Either your solution didn't contain enough Cal-Mag during the veg stage, or you gave too much Potassium in the early flowering stage (an excess of K can lead to a Calcium deficiency). Now, it's too late to do anything about this, you should start the flush very soon so there's no chance that any nutrient will have time to propagate into the plant's system and fix deficiencies before the flush. Just keep that in mind for your next run and try to stick to a Cal-Mag routine in your feedings until the late flowering stage. I'm using coco and I usually give 0.4 to 0.8 gram of cal-mag per liter of water. Hope this will help, keep us up-to-date and enjoy your harvest :facepunch: