Tend to smelly compost
If you are worried about sour smells coming from your compost piles, it’s time to take action. Bad smells can be the result of too much nitrogen in the mix, an excess of food scraps, too much water or not enough air. The best thing to do is empty all the material out onto a tarp or plastic sheet. It will probably be quite wet and sticky. Mix through high-carbon material such as dry leaves (below), sawdust, straw, shredded cardboard or newspaper. These help to soak up the excess moisture and balance out the excess nitrogen. Aerate the pile by giving it a good turnover with a fork. Let it sit for a couple of days, adding more carbon if necessary, then return it to the compost bin. Avoid wetting the material for a while and cover it to keep the rain out. Whenever you add high-nitrogen materials, such as fresh grass clippings or food scraps, be sure to always balance them out with a load of dry, high-carbon material, and turn the heap regularly to keep it well aerated.