Advice on weighing certain foods

FiiiiFiiiFlowerTot

Hello

I have recently invested in some food scales, great. However, i tend to cook a lot of my veg and chicken from frozen (i know its not very good but its convenient at the moment) anyway, i need advice on when do you weigh this vegetables and meat? before its cooked and its still frozen, or after wards?

Also, its shocking to see how little 100g of things is!!! Potatoes are heavy ill tell you that!!