This is an Amnesia Haze auto-flower on day 65 from germination (six weeks since beginning of flowering.) It is in FF soil. FF “trio” was being added to water at 35% of the FF feeding recommendation. The pH of the water after nutrients are added is 6.4/5. It was suggested that “nitrogen toxicity” was an issue causing the yellowing leaves. It has been a week since the nutrients have been adjusted to exclude nitrogen and include Cal/Mag. The yellowing of the leaves is spreading…is this a continuation of the “nitrogen toxicity?”
Other possibilities to yellowing leaves included over/under watering? I water the plant every 36 hours or so. A quart of water begins runoff. The soil is quite dry by next watering. It was suggested that over/under watering can be determined by “thin dry leaves” or “thick swollen leaves” but I really cannot tell either way. The yellowing leaves do not have any noticeable difference in texture until they just up and wither (die.)
I think I am going to make it to harvest…but will the quality of the smoke be impacted?
If you do have a problem then runoff PPM and runoff pH will give you a good idea of what is going on in the soil. You should check them to verify acceptable ranges.
That said, it is normal for cannabis to yellow and even drop some of the lower fan leaves as the plant’s maturity progresses.
Looks more like mag to me check this out. Plus as said it’s pretty normal for a plant to cannibalize itself as you get closer to harvest. Here’s a pic I like that helps with diagnosing
She’s getting close to her end for sure, just a couple, fee weeks left.
To me it looks like mag deficiency. You said your feeding her cal mag. As long as the mag isn’t locked out from high Phosphorus or calcium levels she should be able to absorb the cal mag. Magnesium is washed away easily with frequent watering and flushing but I don’t see that to be the case here.
Just my 2¢ more knowledgeable and experienced eyes need a look. The yellowing between the veins on the lower leaves are what lead me to think Magnesium. My eyes aren’t that great, let’s see what others say
Yes, just recently started adding Cal/Mag about a week ago. pH is 6.5. I read where pH is acceptable in range of 6.0 to 7.0 so I figured 6.5 was normal.
Update: @covertgrower@Eagles009 Would you please look at this? Based upon some things I read I decided to “flush” the plant. For one, I had not yet flushed and, two, I recently changed nutrient mix. So, on this occasion of the watering regimen I decided to flush and hope I have not erred. The flush was with RO purified water with a pH 6.7. The runoff readings were pH 5.8/5.9. EC = 1.1 (550 ppm.) According to what I had read a second flush was performed about 20 minutes later. Readings from that flush using the same water was pH 5.8/5.9 and EC = 0.8 (400 ppm.) Are these numbers indicative of a problem? Are they in range? I am currently feeding Buds and Bloom, and Big Bloom at 35% with Cal/Mag having been added three feedings ago. Thanks for the feed back!
I believe you are looking for a run off range somewhere between 800-1000 for where you are currently at in flower. Let covert or someone else confirm that though because I don’t actually measure runoff of my plants, hardly ever. pH looks good. So to my understanding your first runoff number, 550 ppm, is telling you that your plant was a little hungry. Again im just remembering things I’ve read here not practiced.
Thanks. Sounds like I need to up the nutrients a bit at this last stage. Not measuring run off…nor would I but I am trying to figure out these yellowing leaves. Stopped the nitrogen as was suggested but yellowing is spreading. Will it revert to a healthier looking green or is it too late in the growth?
@dcdkk437 You have already received some great help, and you are doing well problem solving. I just finished my first grow with AMN. While all plants are different, and growing environment varies, mine went 11 weeks flowering, 15 weeks total, and I should have let it go another two weeks, at least.
Your buds will continue to fatten. They look good.
Thank you for the feed back. Sorry for the late response…I’ve been on the road. This is my first attempt at growing. Seedling transplant was Sept 20. I first noticed tiny pistils forming on Oct 14 so that puts me at roughly 7.5 weeks into flower. I have realized that I am not giving enough nutrients. One problem was increasing FF nutrients lowered pH and I did not yet have pH UP to balance the pH back to 6.5 Just picked some up. I appreciate the time frame you gave…it really helps me to stay patient!
