I was talking to a grow store manager recently. He has a science background it sounded like, and he surprised me by saying that there's no need to have Fertilizers like Bat Guano deeper than 6 inches.
Because that top 6 inches of soil is where the aerobic bacteria is, he said.
The aerobic bacteria being the bacteria that digest the bat guano, part of the (aerobic) Micro-herd that deliver nutrients - their excretions - to the roots of our favorite plants.
He said that deeper than 6 inches, in the normal grow set-up, the bacteria are anaerobic, and don't convert the bat guano into something the Cannabis plant can consume. So there's no need to mix bat guano into the soil deeper than 6 inches. He said.
That picture is a gray scale of part of the 22 acre Sonoma Compost facility. I took a class from Will Bakx, the Technical Director at Sonoma Compost.
The tour of their facility was one of the coolest industrial shows I've ever seen. Those wind-rows are 200+ yards long. 25 to 30 feet wide, 12 to 15 feet high. All cooking at about 160 degrees F.
That's where they need Will. The mix has to be very precise in order to get the 160 degrees F. Water is also an essential ingredient. Without water it doesn't heat up.
The aerobic bacteria need water to de-compose the yard waste (leaves & grass clippings) and ground up chickens and chicken feathers that are the standard inputs for industrial hot composting operations.
It is region dependent. Sonoma Compost has access to tons of mallard duck poop, so that goes into one of their mixes to augment the Phosphorus and Potassium.
I mention Will in the context of the statement about aerobic bacteria only going 6 inches deep, because the windrows at Sonoma Compost are 12 to 15 feet high, and it's all aerobic bacteria
that are producing those temperatures. So there is a case of aerobic bacteria 12 feet deep.
It would be great if we could watch Will and the grow store manager debate this and sort it out.
Side-stepping the exact depth of how deep you can find aerobic bacteria doing good work in Cannabis gardens, the one take-away from talking to the Grow Store Manager is -
AEROBIC BACTERIA ARE GOOD.
Imagine planting Cannabis plants on top of almost finished wind-rows 10 feet high. I say almost finished because after 10 weeks, the compost they sell is sometimes still steaming. The aerobic bacteria are still doing their thing.
That's what I'm talking about planting in. If Aerobic Bacteria are Good, wouldn't you want to design your soil base so that it was ALL Aerobic Bacteria ?