Calculate the amount of organic fertilizer needed by using the soil test nutrient recommendation, the concentration of nutrients in the fertilizer selected, and the size of the area fertilized. Garden and landscape areas are usually different than 1000 square feet. Estimate the size of the area to be fertilized by pacing or using a measuring tape to determine length and width. Multiply length by width to calculate area. The garden area is 1400 square feet.
Many organic materials contain high levels of salts.
These salts will burn plants if organic materials are over-applied. Organic materials can be broadcast on the surface and tilled or watered into soil, or applied in a narrow band on or beneath the surface. A common fertilizer spreader will often work well for applying small quantities of organic fertilizer. Rotary spreaders may broadcast organic materials in a 5 to 10 foot wide path but with less uniformity and rate control than drop spreaders. Many organic materials contain high levels of salts.