I use coconut coir to start all my seedlings. It is wonderful because there is no organic material in it therefore no food to attract gnats who's larvae feed on the roots of young daylilies planted in potting soil. I have even left out a couple of containers of daylilies planted in coir over winter (not intentionally but they got forgotten in all the rest of the work I had to do ) and discovered that the daylilies do return . I also have used it to amend gardens in my yard that are very heavily laden with clay to lighten up this soil. I highly recommend it . It also helps to hold moisture ( like peat) but is a renewable resource unlike peat.

I understand what you are saying in particular about gnats and seedlings. Although I do use some of the commercial potting mixes for annuals which probably contain peat, I don't use peat itself in any of the mixes I personally blend. This coir sounds better on a couple of counts if I ever do. I appreciate you passing on your experience. It was all new to me as a potting soil amendment.........Maryl