In gardening

Gardening

Gardening is the practice of growing and cultivating plants. Ornamental plants are normally grown for their flowers, foliage, or overall appearance; useful plants are grown for consumption , for their dyes, or for medicinal or cosmetic use...

 and botanical

Botany

Botany, plant science, or plant biology is a branch of biology that involves the scientific study of plant life. Traditionally, botany also included the study of fungi, algae and viruses...

 terminology, a volunteer is a plant that grows on its own, rather than being deliberately planted by a farmer or gardener. Volunteers often grow from seeds that float in on the wind, are dropped by birds, or are inadvertently mixed into compost

Compost

Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. At its most essential, the process of composting requires simply piling up waste outdoors and waiting for the materials to break down from anywhere...

 before it is used.

Unlike weeds, which are unwanted plants, a volunteer may be encouraged once it appears, being watered, fertilized, or otherwise cared for.

Volunteers that grow from the seeds of specific cultivars do not reliably "come true", and often differ significantly from the parent. Such open pollinated plants, if they show desirable characteristics, may be selected to become new cultivars.

Agriculture

In agricultural rotations, self-set plants from the previous year's crop may become established as weeds in the current crop, to which they may pose a problem. Example : volunteer winter wheat will germinate to quite high levels in a following oilseed rape crop, usually requiring chemical control measures. In agricultural research, high purity of a harvested crop is usually desirable. To achieve this, typically a group of temporary workers will walk the crop rows looking for volunteer plants, or "rogue" plants in an exercise often referred to as roguing.