Possible Phosphorus Deficiency

I hate for my first post to be asking for help, but I'm at my wits end. I'm on my first ever grow that I started form seeds that I've collected over the years and the plants have been doing great until recently. One of my plants started to get these really dark brown/greenish spots that would kill a leaf and move on. I did some research and it appeared to be phosphorus deficiency so I bought some Shultz 10-15-10 plant food. I waited about a 2 weeks, but it just kept spreading and killing off leaves so I transplanted it into some new soil because I unfortunately I used regular garden soil so it was pretty compact (I read that soil compaction can lead to deficiencies).

So it's been about a week and it's still getting worse. The plant was pretty bushy before and now most of the leaves have fallen off and the spots are now appearing at the top of the plant on fairly new leaves. I'm afraid it's about to die. Could it be a type of mold?

Is there anything I can do?

I've tried searching for the problem, but I always end up on phosphorus deficiency. So any help would be much appreciated.

did you check your PH ? and did you check for bugs ? beside that your could be right ? but dunno brown spots do let me to think P. Def. as well ..

learn from it, get some good light soil with a PH between 6 and 7 and with about 20-30% Perlite in it for your next grow ..
some good pots in different sizes (cups/3G/5G) with good drain holes in em would also be a good move ..

there looks to be a p def. but i think your problem is lockout.figure out why its being locked out, then cal/mag along with nutes....peace

Slipon said:

did you check your PH ? and did you check for bugs ? beside that your could be right ? but dunno brown spots do let me to think P. Def. as well ..

learn from it, get some good light soil with a PH between 6 and 7 and with about 20-30% Perlite in it for your next grow ..
some good pots in different sizes (cups/3G/5G) with good drain holes in em would also be a good move ..

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PH levels completely slipped my mind. I never got around to testing the soil because when I first started to grow them they were all growing perfectly so I never got around to getting a tester. I did notice one tiny bug crawling on top of the soil when I transplanted it. It was black or really dark brown and about the size of a flea.

I'm going to go buy a soil tester right now and I'll post the PH levels when I get back.

EDIT: Should I test the new soil or dig a little and test some of the old or just do both?

Could be zink deficiency.

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You should test the pH of your water. Know in advance that some folks will respond to this and say they have grown fabulous marijuana without ever testing their water pH, and they are certainly telling the truth. BUT... that just means they were fortunate enough to have water that was the proper pH. I have seen plants do exactly as you are describing due to high pH (alkaline) water. Water was around 8.3.. cannabis prefers 5.7 to 6.3... and this pH issue with the water will prevent the plant from taking up nutrients as it should. Believe that.

Looking like a P deficiency to me too. Prolly caused by PH issues. CHeck out link pics
http://growweedeasy.com/marijuana-symptoms-pictures

timbo123 said:

You should test the pH of your water. Know in advance that some folks will respond to this and say they have grown fabulous marijuana without ever testing their water pH, and they are certainly telling the truth. BUT... that just means they were fortunate enough to have water that was the proper pH. I have seen plants do exactly as you are describing due to high pH (alkaline) water. Water was around 8.3.. cannabis prefers 5.7 to 6.3... and this pH issue with the water will prevent the plant from taking up nutrients as it should. Believe that.

Click to expand...

Sorry not for soil though. I grow in 6.5 to 7.5 and I'm fine.

I did a few tests. My water and soil both seem to hover around 7.0