Soil Block Mix

Hello All, I'm fairly new to all this and would appreciate any advice. I would like to begin making soil blocks, but I am not fond of the idea of using perlite or vermiculite. I know Eliot Coleman uses perlite, and every farmer that I've worked for also used it. So, I have two questions:

1. Are there alternatives?

2. Can anyone suggest a soil mixture that has worked well for them when planting from seed?

I apologize if there is a thread already answering this question!

Cheers, Kyle

Just out of curiosity, why are you opposed to perlite?

I've read in the past that rice hulls will work. The point of the perlite and vermiculite are to increase drainage, increase water holding capacity, and provide places for nutrients to bond to, right? I'd think something else small and spongy or puffy could work. Sawdust might be cheap and easy?

I've traditionally made blocks using coarse sand instead of vermiculite. This is the first year I've used vermiculite in accordance with Eliot Coleman's recipe, and I have to say that it makes better blocks...lighter texture and they come out of the mold better with less deformation. There are no hard rules...experiment and have fun!

I am opposed to the mining practices of perlite/vermiculite. I have read that the mining of perlite is not too hard on the natural environment, but it still makes me wary. Thank you both for your replies!

I only use the fine grade perlite, which is much smaller sized, in my soil block mix. No matter if I'm making the 2" or 1/4", but very little in my 1/4" mix. I use coco coir to hold them together better instead of peat. Using vermiculite is not a good idea as once it's compressed it stays compressed- since the soil blocks are make with a press, that doesn't make much sense. I think Coleman stated that in his show Gardening Naturally. I use vermiculite in my potting soil mix though as it is really good at holding moisture.