Possible plant deficiency problem any help would be appreciated

I opened my tent 2 days ago and noticed black spots on several leaves in the same exact spots along with some yellowing. This is the second time I’ve dealt with this same issue and this plant and transplanting last time cleared up the issue, my other plant I have going looks great and receives the same exact everything. I’m using Mega Crop, no nitrogen calmag, and distilled water with the ph of 6.3 and my medium is organic promix soil with added perlite. I tested my soil ph yesterday and both plants are 5.83. I then decided to feed both plants using mega, calmag, and well water with a ph of 6.5 to see if there’s a change. I’ll post later when I open the tent if there’s a change.

Is this a nutrient or micronutrient deficiency?

Do I need to switch from distilled water to well? My well water is a solid 7.01 always with a ppm of 240.

Also, do I need to raise the ph of my soil using lime?



Any help would be appreciated. Thanks and have a great day!

StonedGimp said:

... noticed black spots on several leaves in the same exact spots along with some yellowing..

Click to expand...

Hey @StonedGimp you may well have a "deficiency problem," maybe magnesium. How much CalMag have you been adding? Perhaps someone with experience using Mega Crop will come along and ask how you are mixing. I wonder about your nitrogen level. It's maybe hard to tell from you photo, the light you are using, the strain, etc. but your leaves apear a bit lime-green, which is why I wonder about the nitrogen level. Good luck!

Well, your soil pH is perfect for Hydroponics but not for soil... I'm sure you know that already. You should be sitting around 6.5 instead. Your leaves are really lime green and should be darker. I would adjust the pH level higher for one to see if that first fixes the problem before adding anything. Check your run-out water and try to get around 6.2 -6.5 in that area and see what happens.

Serpentz said:

Well, your soil pH is perfect for Hydroponics but not for soil... I'm sure you know that already. You should be sitting around 6.5 instead. Your leaves are really lime green and should be darker. I would adjust the pH level higher for one to see if that first fixes the problem before adding anything. Check your run-out water and try to get around 6.2 -6.5 in that area and see what happens.

Click to expand...

I‘d water with the 7 ph you initially have and the PH will raise. calmag and N is also looking rather low.

Also, get some microbes in and use a foliar spray, they help to get a good Ph

Testing run off in soil will only confuse the problem.Distilled water is a very poor choice,well water adjusted to ph 6.3 is better.

Bear in mind if you're using the Promix MP Organik, it contains coco, which has a tendency to hold onto Mg. You may need to adjust your feed for this fact as your girl looks a little short on Mg. As nmibud mentioned, the distilled water is not your best choice...I'd stick to your well water and make the necessary adjustments for the additional ppm's it lends to your feed. Good luck friend.

Sorry everyone for not getting back on here sooner, for some reason I never received notifications. I watered plants with 6.5ph well and upped the mega crop. Immediately the plants began getting darker and growing faster. I checked the soil a few days later and it was at 6.47 so I then added some lime to the top of the soil and fed again using water with a ph of 6.4 and again fed with the extra mega crop. Most of the yellow discoloration has disappeared and everything looks great now. I also flipped to flower a few days ago and I’ll be on the lookout for problems again. Thanks for all the replies and I’ll be sure to check the site instead of just my email. Also, I’m using promix organic in a black bag from the local hardware store. I’m not sure if it is the coco version or not.

The plants looked great after the 6.4 water so during the next water I dropped it back to 6.3 and once again began showing signs of lighter leaf coloration. I watered again once the soil was dry with added Mega for flower and added bud explosion then adjusted to 6.5 and the leaves are now dark again. I’m thinking I should just stick to 6.5 and go with that.