Can I compost kitchen scraps with garden waste?

The answer is a cautious yes because unlike garden waste, kitchen scraps can attract rats, flies and other pests.

You can compost garden waste with kitchen scraps as a minor component in a traditional compost bin, provided you are selective in your scraps and mix often to add air (oxygen).

You must also have a balance in carbon and nitrogen macronutrients. A balanced mix results from combining wastes rich in carbon with others that are rich in nitrogen:

Carbon waste

Garden waste is generally carbon-rich. How rich in carbon depends on its makeup. Twigs and bark are very rich in carbon, and take longer to break down than shrub trimmings, tip pruning and fallen leaves.

Carbon waste from the kitchen include food high in carbohydrates (e.g. bread, pasta, noodles, rice) and fruit scraps. Adding them to garden waste slows composting due to an increase in total carbon.

Nitrogen waste

Grass clippings and weeds are a garden waste subgroup which is unusually nitrogen-rich. They mat easily to impede composting, so add them as thin layers between carbon waste.

A small amount of organic fertilisers such as blood and bone or poultry manure can provide the required nitrogen for garden waste.

Kitchen scraps are typically nitrogen-rich, but will quickly start stinking if you don’t provide enough air. So, either aerate frequently by mixing your wastes in a traditional compost bin, or recycle with Bioverter, a composting innovation that aerates wastes by itself.

Balance carbon and nitrogen

Balancing garden waste is hard because its huge range of carbon content. How much nitrogen is required varies with your garden waste mixture.

On the other hand, kitchen scraps are generally fairly well balanced and composting them using Bioverter typically requires a weekly carbon waste top-up. Turning your scraps into compost is easier with Bioverter.