Hello and Help!

  • Thread starter DustyCorners
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Hello Everyone,

I'm from central Kansas and looking for some help! This is our second grow and we are still learning the process. I'm growing a CBG strain inside my greenhouse and have noticed some issues. The plants are getting supplemental lighting from a 1000W HPS fixture. They WERE getting a watering every day for two days then on the third day a feeding. The watering was a 6.0 PH and the feeding amount was 600 ppm. The plants are getting water/feed through a drip system and are sitting in a soil called "SunShine Adv Mix 4" and the plants are in a 10 gallon smart pot. Our first thought was the plants might be getting over watered or have some type of root rot. So we stopped watering/feeding in hopes to see some improvement. The conditions in the greenhouse have been 70-78 F. The humidity has been hard to keep up since we are in a dry time but is avg at 40. Lighting hours have been 16 hours. We are also pumping in 1300 ppm of Co2 in the early afternoon.

We have noticed some plants are starting to turn yellow (most spotted yellow) some plants even have a dark green or dark brown spotted area. The leaves are also curling up, hopefully you can see these issues in the photos.

Any suggestions would be greatly appreciated.
Mr. Molecule

Mr. Molecule

The watering was a 6.0 PH

Right off the bat that sounds like too low pH, that is probably what did it. Looks like Ca and/or Mg are getting locked out. I've never grown in Sunshine Advanced Mix 4 but I assume it's like ProMix, and mostly peat. Peat is by nature acidic, so the last thing you'd want to do in a peat-based mix is apply water that is way too low in pH. I think you should have been maintaining a pH of about 6.6-6.8 as is often done in soil.

Remember pH is an algorithmic scale, so a pH of 6.0 is not merely six "points" or tenths lower than 6.6, it's six times lower. So like 600% lower.

If I were you I'd water at the next watering with 6.6 or 6.7 and test the runoff that comes off for its pH. I'll bet you'll see it very low (at least 6.0). Basically you need to reset the pH of the entire pot. I can see in the photo that it's climbing up the plant. You don't have much time to fix it. Good luck.

EDIT: Well I'll be a monkey's uncle. I just ran across this web copy for your mix:

Composed of Sphagnum Peat Moss, Sun-Coir, RESiLIENCE®, Perlite, Dolomitic Limestone, Organic Wetting Agent, Proprietary Blend of Endomycorrhizae. Sunshine® Advanced #4 is formulated to stabilize at pH range of 5.8 – 6.2.

So according to that, you should be right on with your 6.0 pH. Hmm, now I don't have a clue what's causing your problem. Maybe I should delete my post...
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