Besides their initial use, crops can also be used for other tasks. Indeed, one of the principles of permaculture is that every plant should have at least 3 uses. Is this the same as "Stacking Functions"?[verification needed]) Depending on the plant in question and the environment it is used in, these other functions can be:
- use as insect repellent: some herbs can also repel insects.
- shade: under a fruit trees can be a great place to sit, especially in summer.
- companion plants: some plants can stimulate the growing of other plants
- enriching the soil, through nitrogen fixation, organic matter or encouraging soil organisms
- forming attractive and fragrant flowers and leaves: these can be pleasing to people, and stimulate local biodiversity (attract/maintain pollinators)
- Some plants have more than one plant part that can be eaten; ie fruit aswell as leaves, stems, flower heads, ...
Plants which are well known for one purpose sometimes have other valuable uses which are neglected. For example: