I am working on a Girl Scout Cookies Extreme autoflower and things have been looking beautiful until the last couple of days. I’m about 4 weeks into bloom (61 days/9 weeks total since start) and started getting some red/brown spots on some leaves. They don’t seem to rub off so I’m hoping it’s not fungal, and I don’t see any of the telltale signs of pests that I’ve seen online, but I’m still new to this so I’m not sure. I’m in soil and feedings and the soil are balanced to between 6.0-6.5. I’m using FoxFarm Ocean Forest and FoxFarm Liquid Nutrient Trio (in approx the middle of the recommend dosing strength)
Everything seems to be healthy otherwise, so I’m hoping this isn’t something major, but any advice would be greatly appreciated!
If your plant is 9 weeks old and using the FF Trio, it is likely that you have a problem with salt buildup and therefore a very low soil pH regardless of how pH balanced your feedings are. You should also be testing the pH of the runoff so that you know what is going on in the soil. Too low of a pH will lockout essential nutrients and cause deficiencies.
Good to know, thank you! I’m going to start flushing with my next watering. Is there a way to avoid the salt buildup in the future? Was the dosage of nutes too high, or is that just an inherent problem with the FF Trio?
Dosing should be managed by measuring and making adjustments to runoff PPM, which should be ~1,000 PPM.
Unfortunately with FF nutes a salt buildup is inevitable. Even the FF feeding chart calls for 2 to 3 flushes over the life of the plant. Switching to a less salty product like Jack’s 321 can help.
A flush of this type should be done all at once. Use a product like Sledgehammer or FloraKleen as directed and follow that with several gallons of straight water. It will correct your soil pH immediately.
You may also have a problem with mold. What is the humidity in your grow space? Do you have good airflow (perhaps with a small fan moving air around in the grow space.)
Thanks for the additional info on the proper way to flush and for being so kind! Would it be effective to flush with straight water for the time being, with the holidays limiting my ability to get one of those specific products in short order?
I have a small tower fan adjacent to the plants in there oscillating 24/7. For what it’s worth the other plant in the tent (same strain and timeframe, feeding etc) is not showing any of the same issues. Humidity is linked to a hygrometer in there and has been between 45%-55%(absolute max) for the last couple of weeks bloom, mostly around 50%.
That’s what my white widow did. I have it a heavy flush. 4x the amount of water I normally feed. Then she was back to normal a week later. Dried, cured, and smoked super smooth
I will have to get a TDS meter next week to check concentration, but runoff pH was around 6.4-6.5 for both plants with today’s plain water flush. Hopefully this should help get things back on track - thank you!!!
Honestly I never used a tds or ec meter. Probably where I messed up buttttttt all I had was a ph meter and it worked out. I didn’t check runoff or anything.
