created custom soil, was able to create the script

import mods.botanypots.Soil; Soil.create("toxxikz_cane_ores:tc_obluesand", <item:toxxikz_cane_ores:tc_obluesand>, <blockstate:toxxikz_cane_ores:tc_obluesand>, 150, ["rocky"]);

the soil goes into the pot just find, but it wont allow plants to be planted on it.

The same soil outside of the pot has no issue growing plants.

How are you defining the crops?

here is the total code so far

import mods.botanypots.Soil;
import mods.botanypots.Crop;

Soil.create("toxxikz_cane_ores:tc_obluesand", <item:toxxikz_cane_ores:tc_obluesand>, <blockstate:toxxikz_cane_ores:tc_obluesand>, 150, ["sandy"]);

Crop.create("toxxikz_cane_ores:tco_iron_cane", <item:toxxikz_cane_ores:tco_iron_cane>, <blockstate:toxxikz_cane_ores:tco_iron_cane>, 300, ["sand"]);

Crop.create("toxxikz_cane_ores:tco_osmium_cane", <item:toxxikz_cane_ores:tco_osmium_cane>, <blockstate:toxxikz_cane_ores:tco_osmium_cane>, 300, ["sand"]);

Crop.addDrop("toxxikz_cane_ores:tco_iron_cane", <item:toxxikz_cane_ores:tco_iron_sugar_cane>, 1.0, 1, 1);
Crop.addDrop("toxxikz_cane_ores:tco_osmium_cane", <item:toxxikz_cane_ores:tco_osmium_sugar_cane>, 1.0, 1, 1);

Also it will not allow vanilla plants to be planted either in that soil when in a botany pot.

and here is the logs

[08:56:30.220][COMMON_SETUP][CLIENT][INFO] Started loading Scripts for Loader 'setupCommon'!
[08:56:30.756][COMMON_SETUP][CLIENT][INFO] Finished loading Scripts!
[08:57:30.763][DONE][SERVER][INFO] Started loading Scripts for Loader 'crafttweaker'!
[08:57:30.802][DONE][SERVER][INFO] Loading crops.zs
[08:57:30.822][DONE][SERVER][INFO] [Botany Pots] Created new soil with ID toxxikz_cane_ores:tc_obluesand
[08:57:30.824][DONE][SERVER][INFO] [Botany Pots] Added new crop toxxikz_cane_ores:tco_iron_cane
[08:57:30.824][DONE][SERVER][INFO] [Botany Pots] Added new crop toxxikz_cane_ores:tco_osmium_cane
[08:57:30.826][DONE][SERVER][INFO] [Botany Pots] Added dropitem:toxxikz_cane_ores:tco_iron_sugar_cane to crop toxxikz_cane_ores:tco_iron_cane
[08:57:30.826][DONE][SERVER][INFO] [Botany Pots] Added dropitem:toxxikz_cane_ores:tco_osmium_sugar_cane to crop toxxikz_cane_ores:tco_osmium_cane
[08:57:30.826][DONE][SERVER][INFO] Finished loading Scripts!
[08:57:43.810][DONE][CLIENT][INFO] Loading crops.zs

For a crop to be plantable in a soil they must share a category tag. You game your soil the sandy category and then you gave your new crops the sand category, so they do not match. Most of the vanilla crops are looking for dirt as their category.