Permaculture Seed Raising Mix

This post is a follow on from my Thoughts on Growing Seedlings for Transplant. 

In this post, I'll talk about making my seed raising mix with the focus being on the life within this growing media as opposed to the typical focus on moisture and nutrients.

My partners in this exercise will be these guys. Composting worms.

Vermicompost, or worm castings are packed full of living organisms and organic exudates which absorb and regulate moisture within the soil. It also happens to be a nutrient dense medium which means that it's a perfect candidate for a base ingredient in a permaculture seed raising mix.

I already have a vermicomposting system, and a ready (and free) source of high quality vermicompost. I recommend you keep your own composting worms too. Not only are they low maintenance, but you have complete control over what goes in (and eventually comes out) of your system.

The first task in making this seed raising mix is to screen the finished vermicompost. It's loaded with seeds from melons, squash, apples, pears, and the odd banana sticker. So they all need to go.

I used a mesh trash can from the dollar store to do this and it worked incredibly well.

The next step is to assemble the ingredients:

• Screened Worm Castings
• Coconut Coir
• Perlite
• Vermiculite

I decided to use coconut coir as a replacement medium for peat because it's a renewable resource. It tends to have a few chunks and long fibers in there, but they can be picked out easily as you find them. The coconut coir acts as a binding agent and moisture absorbent.

The perlite adds a lot of microscopic surface area for the living organisms to colonize, and it also helps regulate moisture levels.

The vermiculite acts similarly to perlite, but it also introduces trace minerals into the mix. However vermiculite has better water holding capacity than perlite, while perlite has better aeration properties than vermiculite.

Finally, vermiculite is a much better buffering agent than perlite, and acts as a pH stabilizing influence in the mix.

The next step is to combine the ingredients:

• 4 Parts Worm Castings
• 2 Parts Coconut Coir
• 1 Part Perlite
• 1 Part Vermiculite

I was initially taken aback by the cost of the coconut coir. But when I went to measure it out, I found that is comes highly compressed, and it expands a lot so you need a lot less than you think you do.

I chose the ratios printed here for a number of reasons. Typical seed raising mixes that incorporate vermicompost use a lot less of it. However, these mixes are based on traditional paradigms which focus on sterility, air, water, and nutrients. This mix focuses on soil life.

I noticed while doing research online that there are a lot of mixed signals regarding worm castings. A lot of it has to do with people incorrectly assuming that because it looks like soil, it can be treated like soil. This is not the case at all. It absorbs a lot of water. It is incredibly sticky (from the bio-exudates), gooey, and unless you have worms actively turning and aerating it, it will set like concrete.

During my research, I stumbled across this article on growjourney:

How to Make Your Own DIY Seed Starting Mix For Garden Seeds

A lot of what they were advocating fell in line with my objectives, so I stole their recipe. Thanks guys!

The final step involves mixing it all together. You can see coconut coir chunks in there still, but overall it looks pretty much like the usual seed raising mix you buy, if a little heavy on the perlite by comparison.

Overall, I am optimistic for my seedlings. I know exactly what's in this mix, and because I make the worm castings for free, this will probably work out cheaper than buying high quality commercial product.