I blend my own potting soil, but that’s another topic (coming soon). The base for my mix is coconut coir.
You’ll find it, or peat moss, in basically every bagged potting mix on the market. And for good reason - it’s nice and fluffy, so it holds a lot of air. But it will also hold many times it’s weight of water. It’s almost difficult to overwater, although some will manage to.
Coco is also considered to be more sustainable than peat.
You can buy pure coco, ready to go, in bags. But you can save a lot of money by going with the bales. They’re cheaper, they’re sterile, and in my area anyway, more available. That’s really why I started using them - I just couldn’t find any ready-to-go bags at the time.
Hat tip to “Dr MJ Coco” on YouTube. He’s got a good video tutorial on this topic and probably can explain the benefits and use of coco better than I will.
When you’re starting from bales, you of course need to hydrate them first. I drilled some holes in the bottom of this inner tote, which can fit into my large Rubbermaid tote. So it’s like a 25 gallon strainer.
Using these 2 bins (I forget the size and the labels are long gone) I find it takes around 20 gallons of water to rehydrate an 11lb standard bale. And I like to get it to where it’s “soupy” - the coco fiber completely suspended in water. I get my hands in there to break up any chunks. I use pH’d tap water, but I don’t bother de-chlorinating: the coco doesn’t really have much microbial life in it yet anyway.
The next crucial step, is “buffering”. Coco palms tend to grow near the ocean and so they can contain a lot of sodium. Though a process called cation exchange, the coco itself will actually rob the calcium and magnesium out of the soil, and in the process exchange it for a sodium ion - not great for your plants.
So what you do, is rinse it with a cal-mag solution. This will preload the coco so it doesn’t rob the nutes, and at the same time flush out the sodium. I flush twice (it’s a lot of fiber 
).
After hydrating, and between each rinse, I pull out the tote (this might be a 2 person lift) and drain for a half hour or so. Most of the time, I’ll let it soak in the calmag overnight after the first flush. But that’s probably much less important than just making sure to add enough water to where the fiber is suspended in the solution.
So now you’ve got yourself some premium coco coir! It can be used as a substrate for hydro or soil grows - like Dogg Farm “One-and-Done” potting mix!
