hau Dennis, as a rule of thumb you start plants in a medium that retains but yet drains
water, the seeds have enough
energy stored to get them to the first set of true leaves. When my start ups get to that point, I repot into 3 to 6 inch containers that have a sand, compost, soil blend (ratio is 1:2:0.5) This gives the plants the nutrients they need and since I create compost that has a fairly complete microbiome, the baby plants get a dose of mycorrhizae, bacteria along with other fungi, springtails, amoeba, flagellate and other protozoa types and sometimes I find nematodes living in the compost. Once plants are in "growing up soil", you can keep them indoors or out, and adding
lights will help the growth rate and health of the plant.
For cuttings I really like pure sand to start the rooting process, it allows me to water with willow water which gets the
roots growing from the prepared part of the stem. (I like to make four incisions on a stem to give the roots a heads up as to where I would like them to grow)
Redhawk