Another late reply / 2022 bump.
My mate is doing big time research into Black Soldier Fly larvae - he's the principal research officer for a venture featured on Shark Tank.
Their commercial goal is high protein animal feedstock produced from the end-stage larvae fed on farming and vegetable waste. The fly has 7 larval development stages, from maggot to fly - so they freeze dry the critters before their final transformation.
So I got 20 litres of his frass by-product.
That's essentially all the larvae poop, as well as the exo-skeletons they shed along the way. After the initial wormy white maggot stage, they have hard little shells that look more like a little flat armadillo than a worm.
Seeing as this is a academic research and commercial venture, he's got loads of testing and analysis information.
+300,000 microbes per small test sample.
When the frass is dried, that drops to 30,000 - but as soon as you add some nutrients and liquid, that rockets back up to crazy numbers.
Very high in nitrogen.
And super high in chitin.
My plants are outdoor, in 20 litre plastic pots. Organic living soil made for last year's grow. At least 30% of the volume went through my worm bin, which I fed from supermarket spoilage including a more than a few kilograms of avocados, strawberries, countless bananas, coffee grounds, hundreds of egg shells, brewers spent grain, and fresh kelp harvested from my local beach, and a bucket of prawn shells.
Back to the frass:
I top dressed the soil with a layer about 2.5cm - or an unmetricated inch.
His recommendation is 3% frass by volume due to the high nitrogen.
Now - in my opinion - I can afford to go a little bit higher with levels, because I'm feeding my soil, and not my plants. My soil already has a strong healthy rhizosphere teeming with microbial life, and the rhizosphere feeds on any organic nutrients I add. They in turn shit out their waste in forms that my plant roots can either readily take up as needed, or ignore if not needed.
I also made up a 20 litre batch of fermented compost tea with the frass:
We have 2 plastic compost drums out back that we fill with our kitchen waste, so I poured a litre of water into each, and collected the drippings from out the bottom. It comes out black and thick and rich.
I added about a litre of the dry frass to the 2 litres of black compost juice, about a cup of brown sugar, and a few handfuls of same-day-fresh green lawn grass cuttings, and filled the rest with water.
Within a day, the mixture was fermenting and bubbling, and needed regular burping to avoid a very stinky potential 'explosion'. So the nutes in the compost juice and the brown sugar definitely bring the frass microorganisms back to life and rapid reproduction.
I'm using that tea about once a week, diluting with 3 parts water.
Every now and then, I remove my 5cm bark compost mulch layer from the top of my pots, to uncover the soil surface proper - and that is always rich and dark and damp thanks to the sun protection which allows topsoil microbes to thrive instead of baking dead dry under the harsh African sun. I spread a sparse surface layer of the chunky bits of the tea - the frass bits and the fermented grass. The mulch layer goes back on top.
Plants are happy and healthy, with deep dark bottle green leaves. About 3 weeks into flower now, starting to emit warm fruity terpenes, and super sticky to the touch.
Minimal bug damage to a few random leaves, no bugs moving in and taking over. Everything looks resilient and balanced.
TL;DR
My approach is to go for as much biodiversity as possible. Different sources, different angles, different species.
That way, if something does start to 'upset a balance' or try to take over, then there's another group of organisms that will take advantage of the excess, and eat the rogues and get them back down into check and balance.
So Frass is a welcome addition to my populations.
( I'll post some pics later when I get my lazy ass out of bed. )
[ edit: spelling and autocorrect changing 'frass' to grass' ]
