It's mostly down to only buying what you need / use really. Frozen vegetables are another option, they are often easily portionable and are a better choice than "fresh" vegetables (source: I used to work in a vegetable packing plant for a summer vacation job; the vegetables we packaged to be sold in shops the day after came from a big freezer / fridge, oftentimes we had to discard whole pallets because the brocolli had gone moldy. I have no idea how long that stuff had been in there, but given the amount of mold it must've been a while)