Hydroponic farms newly planted with bristle blossoms generate dirt delivery errand (see image below). These hydroponic farm tiles had previously been planted with mealwood in order to keep the drekos fed while I sorted out the water and lighting for the bristle blossoms but I expected them to stop requiring dirt when I switched over.
1. Create several hydroponic farm tiles
2. Grow mealwood in them for several cycles
3. Uproot the mealwood.
4.Plant bristle blossoms.