Thank you mindshift. I found out I actually have Mexican plum seeds. Could I use the same potting mixture for Mexican plum seeds? Thanks again.

I would use a combination of peat moss, perlite, and pine bark in a ratio of 3/1/1. You can also use potting mix (not soil) and pine bark. Soil does not work well in pots, does not drain well enough. The clay in soil stays too wet and can cause root rot. If you can find it expanded shale works well in place of the perlite. You want a mix that drains well but also retains enough moisture to not need to be watered several times a day.

The local feed store has expanded shale but it's on the expensive side unfortunately. I'll get some pine bark and perlite or potting mix.

blackwillow, if you are saying the seedling you have is Mexican Plum instead of persimmon, I'm surprised. The book How To Grow Native Texas Plants states that Mexican plum has a dormant embryo that first requires warm, moist stratification for 30 to 60 days that is then switched to cold stratification at 36º to 41º for 60 to 90 days. This mimics a warm, moist autumn followed by winter. Germination can begin during cold stratification, so check seeds regularly. Seeds should be germinating by late February to get a good start before hot weather begins. Still, plants germinate when conditions are right for them. I've had several sowings that appeared to be failures, but the plants came up the next year or even the year after.

Nonetheless, I've found natives to do just fine in local soil. Seriously, natives in native soil—why is that even a question? Obviously, one should make an effort to provide soil with the texture and pH suitable to the plant, but most soils are improved by adding organic matter, especially compost. The mixture of 4 parts potting soil to 1 part native soil is better for tree and shrub seedlings that are not going to be transplanted to a permanent location for at least a year. Peat and most potting soils have little to no nutrient value. Native soil has nutrient value that is made more available by the potting soil or other organic medium.

Mindshift, it shocked me too because right after I found out they weren't Texas persimmon seeds, one had already sprouted. I cleaned the pulp off in a wire strainer and then soaked the seeds in a bleach solution for 5 minutes to kill off any bacteria on the seeds. I also soaked the coffee filters in the bleach solution to provide a sterile environment. Then I placed them in the moist coffee filter, put that in a bag, and then set it on a sunny windowsill. I checked yesterday and 5 remaining seeds sprouted. The first one sprouted after 9 days. Maybe the bleach solution removed some of the germination inhibitors?

I sometimes buy a peat free potting mix from the local feed store for most of my plants. It has pine bark fines, coarse sand, and a little compost. Would that also work? I didn't know native tree and shrub seedlings could be planted with native soil in pots. I wonder if Black Kow topsoil would work?

The reason for not using native soil is the native soil cannot drain like it would in the ground. All the water has to drain through small holes in the bottom and can't drain sideways. I agree if planted into the ground to just use native soils. If the potting mix from the feed store is working well for you, I would use it. Black Kow topsoil is not meant for pots. Works good to fill in low areas in your yard or raised beds.

Ok I'll avoid the topsoil. I have to find spots for the seedlings in my small garden. I may give some to friends? I'm just happy they sprouted so quickly.