Some pesticides can be harmful to humans, but beer may be an organic solution to that problem, suggests a study published in Frontiers in Sustainable Food Systems. A team of researchers, led by Maite Gandariasbeitia from NEIKER-BRTA Basque Institute for Agricultural Research and Development in Spain, has investigated organic by-products of used beer grains (called bagasse) and canola (rapeseed oil) cakes, to find that they make a useful pesticide when mixed with cow manure.

Instead of neat rows of monoculture, forest gardens combine fruit and nut trees, shrubs, herbs, vines and perennial vegetables together in one seemingly wild setting. This type of agroforestry mimics natural ecosystems and uses the space available in a sustainable way. UK-based Martin Crawford is one of the pioneers of forest gardening.