If you mix the two you can get pockets of uneven moisture. Coco lets it run through, soil grabs it. They also react differently to EC / PH changes and buffering capacity. I think it will be all about proportions and quality of your mixing. The closest I can think of is the Kings mix from Royal Gold. Its mainly soil but has coco in there too.
When using solo cups to start plants, it's good to do them with a solid color, or to put your clear cups in a solid color. Light is not good for roots and if they start to get green, you'll have problems later. Good suggestion on holding back water for a day or so.
Thank you I'm gonna let it dry up and I'll stop the clear cups I did do them In foam cups once and they were good but I will transplant them to not clear cups. Thank you!
Thank you I'm gonna let it dry up and I'll stop the clear cups I did do them In foam cups once and they were good but I will transplant them to not clear cups. Thank you!