I purchase potting mix by the truck full to use when upsizing pots or adding to holes for new plants. It is a mix of topsoil and aged horse manure/shavings with a tiny bit of time release fertilizer mixed in. I do not buy any other fertilizer. As a matter of fact, my county is a dry county for the purchase of fertilizer of any time from spring till late fall due to too much being washed into the sewer systems and out to the bay and lakes as runoff during the rainy season. Once a plant's roots grow beyond the soil they were planted with, they slowly adapt to the native soil/sand and aclimate on their own. I do use a good percentage of native plants too to reduce the amount fertilizing needed. Of course, my fruits/veggies may not be as productive without supplementation but that's ok by me. I only grow for my own use and not for commercial purposes.
