Many extreme soil conditions can be corrected through the addition of organic matter. Nutrients that should be available in all types of soil are: nitrogen for leaf growth, phosphorous for root growth, and potassium for overall health. By regularly adding organic matter to the soil, there is less need for chemical fertilizers, since organic matter promotes a gradual release of plant nutrients. Organic matter and soil life keep plants healthy by supplying balanced nutrients to growing plants and fighting plant diseases and pests. Compost in an advanced stage of decomposition (dark and without smell) encourages microorganism activity causing soil particles to clump together and form aggregates allowing for spaces in the soil and increasing its drainage. Chemical fertilizers have a number of disadvantages: they release their nutrients too quickly and there is some evidence to show that plants develop a resistance to inorganic fertilizer methods over time, requiring more and more to achieve the same effect. They also are quick-release fertilizers and can wash off quickly into streams. Keep in mind that healthy soil produces healthy food.