That fruit looks great for a tropical plant growing way up north!
The issue is not the sand. Top dressing with sand, mulch, rocks, etc is a common practice with potted plants that at worst does no harm.
My guess is over watering is getting to it. Try just thoroughly soaking it (as in watering until some starts coming out the bottom of the pot) ~ once a week. The idea is to let the soil dry out a little between waterings. You can always stick your finger into the soil to see if it is still damp to see if watering is needed.
That fruit looks great for a tropical plant growing way up north!
The issue is not the sand. Top dressing with sand, mulch, rocks, etc is a common practice with potted plants that at worst does no harm.
My guess is over watering is getting to it. Try just thoroughly soaking it (as in watering until some starts coming out the bottom of the pot) ~ once a week. The idea is to let the soil dry out a little between waterings. You can always stick your finger into the soil to see if it is still damp to see if watering is needed.