In theory, I like the idea of compostable pots. In practice, I ended up with compostable pots that were growing mold on them before they got planted. Probably, totally, my fault. But the pots had so much mold on them that I would not bury them in transplanting.
After watching some YouTube videos on this issue, I switched over to potting up my early plants into 3 inch net cups....
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The net cups worked much better for me, bottom watering them in a tray, and at the end of 8 weeks growing inside the house, none of them had any mold. Those net cups come in both smaller and larger sizes, depending on what you are starting to grow inside the house and how long you want to grow them indoors.
A big part of me wants to reduce the amount of plastics I use in my gardening. However, if you buy the heavy-duty net cups, you can reuse them year after year. So that made me feel better about using plastic again in my gardening efforts.
Because of those slits in the net cup, the roots air prune themselves and do not develop that spiral of death and get root bound in a typical starting pot. My transplants were much healthier after transplanting last spring, even compared to the compostable pots I had used in the past. The air pruned root structure is just better if the plant is started in these net cups.
Given, I'm not the greatest gardener, and maybe those compostable pots are just fine if you know what you are doing, but I'm just saying that I had much, much better luck with the net cups and bottom watering.
If you are interested in learning more, here is one short video on using net cups...