Organic Matter organic matter Organic matter is formed of living organisms and dead matter that can be added to your soil to increase its quality. Examples of good organic matter for your soil are compost, manure, fish, kelp, coco coir, blood meal, bat guano and worm castings.What makes a good soil? Related Terms Growing Medium / Perlite / Vermiculite / Hydroton / Rockwool / Underwatering / Overwatering << Back to Glossary