Related: How Much Soil Should You Use in a Raised Bed Garden? Making your own soil for seed starting isn't that hard (but we can't compare this mixture ... Compost to Soil Ratios For Your Gardens ...

Thus, bags of potting soil, or garden soil, are intended for in-ground use. Potting mix is not the same thing as soil. “Potting mix contains no soil and is a lightweight mixture that’s ideal ...