Benefits

• Phosphorous is the element that makes it possible for a plant to both store and transfer the energy needed for fruit production. Therefore, crops that lack phosphorous in either their soil or their fertilizers are subject to low yields. The necessity of phosphorous to growing edibles is limiting to organic gardeners, as the use of insoluble phosphates, such as those mined from rock, can be harmful to the environment.
  
  

Drawbacks

• Unfortunately, phosphorous is carried over the soil surface by water more readily than it is absorbed for use by plants. The inevitable result is an overload of phosphates in creeks, streams and lakes, that in turn causes a gross over-growth of aquatic plant life. This over-growth robs the water of oxygen, starving other aquatic life like fish. Therefore, alternative sources other than phosphates must be found for returning phosphorous to the soil.
  
  

Manures

• Animal manures are high in water soluble phosphorous, which is more readily available for plant use. Vermicompost is one of the best sources, as it is the result of worm composting, containing both composted material and worm waste. Beef cattle manure is high in phosphorous, with dairy cattle manure coming in a close second. Composted and processed poultry litter is also an acceptable source. Any manure or compost used on crops should be well composted, defined by an earthy smell with no trace of ammonia.
  
  

Cover Crops

• Another good source of phosphorous is the use of cover crops on cropland and even in gardens. Certain plants draw the element from deep in the soil to the top layers as they grow. They are then cut down or tilled under to make way for the main planting. Hairy vetch is one of the best plants for phosphorous renewal, as are black oats, white lupine and white oats. Cover crops are an excellent, organic way of replenishing cropland and garden soil.