Finished compost will be loose and crumbly and will resemble dark soil. It is an excellent soil conditioner and fertilizer and should smell sweet, like the floor of a forest. When mixed with sandy soil, compost helps retain and hold water. When mixed with clay soils, compost loosens the soil particles and allows for better drainage.
Compost can be used with equal parts potting soil or garden soil for container gardening. The compost adds nutrients and texture to encourage plant growth. Plant in a well-drained container, water frequently and add fertilizer to supplement nitrogen content, which is quickly lost in containers.
Compost can be used as mulch around garden plants, under bushes, and around trees. Spread 2 to 3 inches of compost to help hold in moisture, reduce weeds, and gradually feed organic matter into the soil and plant roots. Compost is especially useful in the hottest and driest periods of summer.
Compost may be added to gardens in the spring or fall. Apply the compost in layers of 1 to 2 inches or add the compost in trenches, furrows, and seedling holes when planting or transplanting.