FloridaGardener's Blog
Nov 15

Written by: host
11/15/2009 9:05 PM

Plants cannot tell the difference between organic and chemical fertilizers so why use organics? While organic fertilizers release nutrients slowly and improve the body of soil, chemical fertilizers impact the health of the soil by releasing salts into it eventually making their way into the ground water.


Chemical versus Organic Fetilizers



Release nutrients rapidly

Release nutrients slowly feeding plants steadily over time.

Fertilizer lost to leaching (water washing nutrients away from plant roots so they cannot be used)

Increase water holding capacity

Leaching can pollute water sources

Increase nutrient holding capability of soil

Mineral salts may build up making soil toxic after continuous use

Promotes earthworms and soil micro-organisms

High chemical levels may repel earthworms and soil micro-organisms

Buffers soil from chemical imbalances

May burn plants (often need to be watered-in after application



Numerous types of organic fertilizer are available:



Bird and animal manure

Source of nutrients and micro-organisms. Must be well aged before applying directly to plants.

Blood meal

Slow releasing nitrogen and trace mineral source. Use sparingly.

Fish meal / fish emulsion

Source or nitrogen, phosphorus, potassium and trace elements. Quick releasing. Has a natural fish smell -- look for de-odorized fish emulsions.

Greensand (a type of sandstone mined from deposits of minerals that were originally part of the ocean floor)

Rich in potassium and micro-nutrients.

Rock phosphate

Helps support blooming of flowering plants

Shellfish meal

Excellent source of calcium, nitrogen, phosphorus and micro-nutrients


Effects of Certain Specific Soil Amendments:



Bind sandy soil

Colloidal rock phosphate

Condition soil – add body to sandy soils and lighten clayey soils

Compost, composted (aged) animal manure

Enhance composting process

Alfalfa meal, blood meal

Loosen clayey soil

Greensand, coconut coir

Promote Large blooms and fruit

Bat guano

Promote root growth

Phosphate rock, bone meal

Promote sturdy plant growth

Blood meal, fish emulsion (or meal)

Copyright ©2009 Paul J. Erdek,


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