I gave the pumpkin plants some CalCarb and magnesium this morning as a foliar application. My soil potassium is high and potassium will often out compete with magnesium in the cations to get absorbed by the roots. As such I apply the magnesium as a foliar application to help the plant get magnesium. My magnesium source is just Epsom salt that you can buy at any drug store.
The next couple of days are going to be warm in Colorado so the CalCarb is used to help the plant with the heat. The CalCarb helps the plant keep water and deal with the heat stress.