Milk and gardening don't mix. Ever.
Milk has fat, sugars and hormones that attract pests and/or clog stomatas (the pores through which the plant breathes) and tends to get sour if left out too long and build bacteria.
Plus, what you want is ionic calcium (Ca++), milk only has various biologically useless calcium salts. Do your plant a favor, buy Cal-Mag or add molasses to your water before watering (2tbs/gallon).