Thats interesting Steve, the things I have read point to the declining return on investment with the higher percentage of VC. This is not to say the plants dont do better with more VC just that not enough to justify using more. Seedlings and small planting tray cells is a different ballgame than an open garden or five gallon buckets so upping the content of VC would be easier on the worm doo budget.

I dont expect much this spring in terms of available castings but have been converting wheat bran into frass at an alarming rate in the mealworm bins and have read good things about using that in the garden too.

Castings are good to start seeds. I made a V in the garden bed with a trowel and filled with about 2-3" of casts. I planted a pole bean seed every 6" hoping for 50% to sprout. Nearly 100% sprouted and grew wonderful and plentiful beans.

Pete

I am unsure if VC in this context refers to vermicastings or vermicompost. That difference might explain the different ratio mixture.

Nexiv

Keep in mind my thoughts are not to add a larger % of a plant mix. What I did was only experimental on a certain hard to root kind of plant. To add a larger % to most garden needs would be a waste of vc in my opinion. Plus it could depend on the availability per person for use.

I was referring to just using casts for starting seeds. The bed was already prepped. I used a few inches of mostly castings in the V groove about 25' long. Beans seeds were spaced every 6" and then gently pushed into the casts about 1 " deep. I had lots of beans.
Worm castings or VC used straight is good for seed starting and rooting various plants in my experience. I get sprouts in the bin often.