Hello. I’m a new grower and I’ve scoured the internet to try and troubleshoot a problem I am having. I am on week 5 of flower and there are brown/necrotic spots on my leaves. The spots seem to begin to appear between the veins of the leaves. I have a one plant setup in soil and I’m using fox farms trio nutrients. I use about half strength in addition to 5mL cal mag. My temps are between 77-82F with humidity around 50% and I pH to 6.3 after I mix everything together. I increased the cal mag to two teaspoons per gallon which is 10mL thinking it may be a deficiency. The package says to use 5-10 mL per gallon. I’ve included some pics to help in the diagnosis. The plant pics are under a blurple LED (sorry for the odd color) but the pics of the plucked leaves are under normal light. Any help/advice would be much appreciated. Please let me know if any additional information is needed. Thank you.
What is the pH and PPM of your feed and runoff? What is your growth media/soil? Looks like you may be locking out nutes,
Have you done the flushes according to the fox farm schedule?
I’ve been pH’ing the water before it gets to the plant; however, I have not checked the run off. I will be sure to do it the next watering. I have flushed the plant three times this grow. Once in veg, once after switching the light schedule to induce flowering, and then again on 21Apr2019.
I forgot to mention the soil was Miracle Grow Moisture Control and I added additional perlite to the mix. I have not followed the schedule exactly. I started with 1/4 nutes and gradually increased alternating with just pH’d water every other one or two feedings.
A lot of growers have said MG soil is not good for cannabis because it slow releases nitrogen. This might be why you are having issues.
They did seem pretty green during veg but since this is my first grow I wasn’t too sure and decided to reduce the nute strength. The pictures above were just taken. Would you recommend flushing and to check the pH run off? Should I just use cal mag and no additional nutes or just water? I’m already in week 5-6 of flower so I’m not sure if there’s much I can do. I’m concerned it will get worse and stunt bud growth.
Yes. You need to understand your input and runoff PPM and pH.