Are you asking about the coir pellets then for starting seeds?

First, they don't have the depth most of us prefer for winter sowing.

If you are asking about sowing in the pellets for other types starting starting seed, like indoors, most people I know have a problem with consistent moisture with peat or coir preformed pellets or pots - although I haven't used the coir myself. I've used the peat, and won't again.

U of Utah published a report on coir a few years ago comparing the loose product with peat that you might find interesting, the results weren't favorable...Note the photos of seedlings.

Here is a link that might be useful: comparison of coir to peat

I tried it for indoor seeds and cuttings, didn't like it at all. They were either too wet... or too dry.

I wasn't using pellets, it's was the brick of loose coir which you soak to expand. I only use potting mix now.

Karen

I mean little square pots made from coir. They are like peat pots, only formed from coir. They are pretty thin walled with lots of air space between the fibers. I filled them with MG and seed starting mix.

I do use the peat pellets. I just snip off the netting before planting out. All are set into under-the-bed storage bins. Less mess for me - lazy I reckon!

I think I received a hockey punk shaped disc of coir in a gift of an amaryllis bulb at Christmas. It seems like it needs to be composted for a while.

I have been wondering about these little coir pots. As a re-cycler, I have saved some of them that came with nursery-grown plants. I did not know if I was supposed to plant the whole thing, so I transplanted the seedlings. They have been sitting exposed to the elements for two winters now and are still in the same state. Glad to have this info.

There is a coir product called Wonder Soil that has some nutrient additives and something to hasten expansion. I think the wafers that were with amaryllis about Christmastime may have been Wonder Soil wafers. It is just now being sold on Amazon and I am trying some for the first time. I sure like the way the little cubes behaved upon the addition of water. Will my plants like it? I haven't tried seed yet.