Its the time of year to feed apple trees, with potassium and calcium. As all garden centres and now closed because of the Coronavirus, is there any home made feed I could make up.
We save all our egg shells .. put them in a tray made of foil and put them in the bottom of the oven. The next time the oven is used they will get baked and become really dry and easy to crush.. that' your calcium.
For your potassium save your banana skins and make a tea.