1.) Do you add chocolate or peanut butter chips to the batter prior to baking?
2.) When done baking, should you frost them?
In the gardening world, the compost are the chips and the mulch is the frosting.
It's the compost that "sweetens" the garden soil. It needs to be infused and mixed into the soil, just like the chips need to be mixed in the batter. And like those chips, a little goes a long way. You don't need a ton of it to make your plants thrive. Compost is the gardeners "black gold". The nutrients are constantly being leached into the soil. When rain washes through the compost, tons of Nitrogen and Carbon are washed downward improving the soil quality.
But the mulch? It's the icing on the cake. Like a thicker frosting, mulch is bulkier than compost and tends to stay in place more than compost would. It spreads easily, covers and protects your soil and plant roots from extreme temperatures, helps retain moisture and suppresses weeds and disease. Beyond all this, it does look good....for a time.