Magnesium deficiency problem Barneys Farm LSD.....HELP

Heres a brief rundown on what I have going on. I have 3 Barneys farm LSD and 1 bag seed growing in my tent. All are in 3 gallon pots, fox Farms Ocean Forest soil. 400W HPS for Flower. They are in thier 4th week of flowering. Soil PH = 6.5-7.0 I have been useing Fox Farms, grow big, big bloom and tiger bloom. I have a soil test kit that I check the NPK and PH, everything with the nutes seems to be at safe levels.
Temps inside range from 65-77, RH has been about 40% since flowering

I have been having issues with the lager fan leaves getting dead spots on them then turning yellow and falling off. This started about the same time I switched to 12/12 HPS. I first thought it was a salt build up so I flushed each pot with 6 gallons of water, I gave them a few days to recoup, then tested my soil and found all my nutes were gone, so I gave them a good feeding and rechecked and everything was fine with my NPK. As you can see my issue as gotten worse, after doing some research I think I have a magnesium defecincy, (dead or rust spots on leaf, tips turning brown and curling up, leaf yellows dryes out and falls off)

So I went and got some Epsom Salt, desloved 2tsp per one gallon of RO water and watered all the plants (1/4 gallon each)......waited a few days to see if problem gets better.......and NOTHING changed. I repeated the process yesterday.

I also mixed a 2% solution of Epsom and misted each plant, both top and uderside.

My questions = Am i on the correct track for fixing this issue? How long should it take before I see results? Should I continue misting and watering with Epsom mixture.......my soil is saturated and I do not want to over water.

I think I have about 4-5 more weeks of flowering, Vertical growth as come to a stop. Bud growth has slowed, but still increasing.

Anyhelp would be great. Thanks stlmatt

the leaves that are spotted already will not get corrected. I had the same problem as well with the same strain LSD on the same soil with the same ph level but using ro water and for nutrients i used gh. When i had this problem i used dolomite lime to spray it. the fan leaves that where spotted did eventually fall off but the new growth was as if nothing ever occurred. it will take anywhere between a week to two weeks to see a positve sign again. thats how long it took me to notice a positive sign.

i dont know if this is the first time you will try lsd,if it is let me inform you that its an amazing smoke. I had the sativa pheno type and she is fucking amazing. i just finished harvesting her about 1 week and half. i smoked a little of it and she blew me away with the type of high it gave me. Its a very very very clear high (like a vaporizer high sort of) but yet it numbed my whole body and face as well. Im loving this strain a lot, its become one of my favorite ones already. i hope yours comes out fine and big fat buds.......

Thanks for the info, Yes this is my first indoor grow ever and will be my first lsd smoke........I still have a ways to go, I just hope this is the worst of my issues. I have learned alot and looking forward to a second attempt, as I know it will only get better.

Should I keep misting with the Epsom solution, I dont want the buds to get damaged or develope rot.

thanks stlmatt

It looks more like a Calcium problem to me, which is VERY common with RO water.

Well I looked into that too, but from the pics I saw and read about it looks more like mag.deficiency to me. I was using well water until a few weeks ago, when I started buying RO water from the store. I was hoping the RO water would help them recover, as I thought my well water might have to many undesovled soilds. I know my well water is very hard, so I think it would have lots of Calcium........the strange thing is all of the plants have reveived the same water, nutes, flushing....everything. The bag seed doesnt have the issue as bad as the LSD, and the two LSD that I didnt top are in better shape then the one I did top. I also think my plants might be rootbound, as I can see roots growing out the bottom of the pots. I put the pots on shims so I can get some airflow under the pots and improve drainage.......should have done that from the beginning.......still learning.

actually it can be both problems. but the epsom salt should take care of it. if not then try using dolomite lime. as far as you question dont add more of it until a week later more or less. If you add it constantly it will make it worse by getting a complete lock out. SO wait it off a bit. if you dont see an improvement then go with dolomite lime. When this happened to mines it was ten times worse so i added (sprayed) epsom salt but i didnt notice much improvement after a week and a half so i decided to move and use dolomite lime. After i sprayed it it took about a week or so before new growth was setting in.

stlmatt said:

Well I looked into that too, but from the pics I saw and read about it looks more like mag.deficiency to me. I was using well water until a few weeks ago, when I started buying RO water from the store. I was hoping the RO water would help them recover, as I thought my well water might have to many undesovled soilds. I know my well water is very hard, so I think it would have lots of Calcium........the strange thing is all of the plants have reveived the same water, nutes, flushing....everything. The bag seed doesnt have the issue as bad as the LSD, and the two LSD that I didnt top are in better shape then the one I did top. I also think my plants might be rootbound, as I can see roots growing out the bottom of the pots. I put the pots on shims so I can get some airflow under the pots and improve drainage.......should have done that from the beginning.......still learning.

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Having same problem with my LSD, seed and clones, same nutes, soil, ph. Using distilled water here with 2kw HPS and C02. I was on calcium at first but it just cant be as I add calmag with every fert, as well I dont notice any stunting and buds continue to swell but not as dense as I had hoped. Since the issue is happening top down for me that kind of rules out Mg which would start from the bottom. I think now maybe a mix of K, Fe, and Mn defs so im going to start upping the amount of tiger bloom and solubles to the recommended dose in the FF sched.

Also you mentioned that you ae using well water. Does this run through a softener? If so you wouldnt have so much calcium as you do sodium as the softener uses sodium to displace the calcium in the water. This could quickly cause salt build ups. I had my water tested and it was well beyond the recommend levels for sodium but not a trace of cal/mag found. For this reason I use distilled as I have well + softener.