In most areas, the native soil may be low in nutrients and have poor texture as well. To improve the fertility and texture of your soil, you can add soil amendments.
First, test your soil to see what nutrients it may require by picking up a soil test kit at your local cooperative extension office.
Compost – is decomposed organic matter. It increases the fertility of your soil by slowly releasing nutrients and it improves the texture of your soil and its water-holding capacity. If you only use one soil amendment, use compost.
Manure – comes from a variety of sources: bat, cow, chicken, horse and rabbit. Manure contains nitrogen that is slowly released and also improves the texture of your soil. Make sure to use ‘aged’ or ‘composted’ manure that has been aged at least 6 months or it can ‘burn’ your plants.
Blood Meal – yes, it is made up of blood from animals. Blood meal is a natural source of nitrogen, which is slowly released in the soil.
Bone Meal – is made up of ground up bones from animals and is a good source of phosphorus, an important nutrient for fruit, vegetable and flower formation.
Mix a combination following package instructions on how much to apply. Use before planting or add smaller amounts around your existing plants and lightly rake in about 1 inch deep.
Source: Birds & Blooms