I’m confident that I can keep fungal losses minimal with what I’m doing, but always looking to improve the odds. I’ll share what’s worked (not 100%) for me
Location
Willamette Valley, Oregon, where the rainy season (ie, high humidity and frequent light rains for the next 6 months) can start in September
Setup
a couple thousand plants growing under plastic-covered hoops. Plastic stops about 5’ above the ground, and the cover extends at least 18" past the canopy on all sides. A mix of giant and medium sized plants plus one last-minute “sea of green” hoop. Living soil using a version of Clackamas Coots’ regimen
What’s being done now
manual cleanup of plant interior and bottoms to improve air flow. Not lollipopping; we can sell popcorn to processors
Tops scrogged and bent down to discourage giant, moldy buds
bottom of cannabis plants pruned, and companion vegetation mowed, to create at least 10" airspace between ground and vegetation
Entire grow recently sprayed with micronized sulfur + wetting agent to knock out russets, so there isn’t going to be much in the way of above-ground fungi for the next week or two
Bacillus Subtilis run through irrigation system (low-profile micro sprinklers) to discourage mold and mildew on companion plants.
Plants are getting silica supplements through irrigation
manual spraying and removal of mildew-hosting weeds
Plans
Several worker-hours per day dedicated to monitoring plants for pests/mold/etc. As soon as I spot any, I show it to every field worker so they can recognize it in the future
Physical removal of affected plant matter followed by localized potassium bicarbonate sprays
Giant electric fans blowing through hoops each morning
Wondering how late I can really get away with subtilis foliars, because no matter what the bottle says, the stuff smells like crap
Wondering how late I can get away with potassium bicarbonate foliar without affecting flavor, too
@drhemp I was curious about how late a grower can spray with products affecting the taste too. I had received conflicting opinions of our Mildew Cure product sprayed on plants just prior to harvest. Some assumed that it would leave a Garlic taste but I had testimonial’s of a grower using it right up to harvest and he claimed it did not affect the taste. My suggestion is to try to avoid sprays at least 2 weeks prior to harvest.
This is the ingredients of Mildew Cure
30% Cottonseed Oil
30% Corn Oil
23% Garlic Oil
17% Inert Ingredients
Oleic Acid, Lauric Acid, Sodium Bicarbonate, water
When its about PM , only clean genetics/clones , if they are not clean nothing its helping .
We grow in North California and we havent seen recently PM in our Greenhouses , since we change the source of clones . Our IPM for PM and Molds is : ZeroTol from Biosafe , Regalia from Marrone and SafeSulfur from Safer Brand ( 3 times weekly ) , and it works , what works from this three i am not sure
If anyone’s interested in an update 2 weeks later -
The rainy season came early and hard here, and there are scattered instances of bud rot, but not that much considering how many moths have been around this summer (despite multiple BTk applications).
I’ve been dedicating a couple of worker hours per day to visually monitoring for pests and mold/mildew, and starting tomorrow I’ll have 3 or 4 guys sweeping through in series twice a week until harvest. By in series, I mean every worker checks every hoop with their own unique set of eyeballs.
Workers are gloved and have two buckets, one full of Milstop for sanitizing and one half-full of Milstop, for infected plant matter
When they find a spot of botrytis or a leaf with PM, they wet a glove with Milstop, wrap their hand around the bad part to minimize spore spread, cut/pull it off (along with 2" of neighboring material if it’s bot), put it in a bucket of Milstop, then dip their gloves in the “clean” bucket of Milstop
This is basically the routine I’ve used on my personal plants at home in the Coast Range foothills, where it’s usually much cooler and wetter than my workplace is
I’ve used Serenade (bacillus subtilis) 1 week before harvest, and even though it smells like butt when you spray it, I noticed no weird taste or smell in the final product. Same for Trifecta, which has a formula similar to Mildew Cure’s and a really strong smell.
Substances that have a strong smell are often ones that dissipate quickly; that’s why so many molecules of them make it to your nose
Wow, that’s a no-messing-around antifungal regimen you’ve got there! Those spores are doomed =)
Strain makes a huge difference, but we’re running about 30 different ones to see what thrives in the local environment. Many of the plants that do best in our greenhouse are sucking outdoors, and vice versa.
Of these 30, I see maybe ten that I want to run outdoors next year
I feel like spraying anything so late on buds will just do favor to the molds. I have almost same routine to identify molds , cut it , sterilize the part of the plant where it was , and sterilize the equipment . I use ZeroTol 2.0 for sanitizing , but again sanitizing it does not meaning anything if we are honest , the spores are everywhere in the air and most molds are systematic , meaning they are inside in the tissue and waiting perfect conditions to spread . We use fans in our greenhouses ,we have a lot ventilation and we keep everything on maximum , on that way prevent damp and wet spots , we pray and wait if we can finish the full cycle if not we cut a week before …
Whats the best way to clean and sanitize a grow tent - #5 by devjyarn this post has a document with descriptions of and treatments for almost every greenhouse crop in North America. Spraying leaves with water is actually a treatment for powdery mildew on greenhouse cucumbers. The section begins on page 437.
