Seaweed is an excellent source of calcium and potash. Prior to using seaweed though, be sure to wash it thoroughly to remove the salt. Dig it directly into the soil or compost it. It may be added to the soil or compost pile. Be sure to allow them to rot well in the compost pile before using as pieces of the roots and seeds may re-grow where you least want them to.
Green manure helps to add body to sandy soil.
Because these fertilizers are relatively simple in structure, they break down and are available to plants rather quickly. Fertilizers are available as 'Complete Fertilizers' with varying degrees of chemical compositions or as individual chemicals such as Nitrogen, Phosphorous or Potash. In either case the fertilizers are also available as timed release or quick acting. Artificial manures are often more expensive than organic fertilizers, but tend to be easier to use, less odorous and may be stored longer without deteriorating. They can not, however, add texture to sandy soils as can organic manures.