Inorganic vs. Organic Fertilizers

In most cases, the soil in our backyards or pots does not contain enough of the nutrients plants need to survive. Our sandy South Florida soils are particularly challenging to keep healthy. Just like many people take vitamins to supplement their daily diet, fertilizer provides the extra boost plants need to grow.

There are two types of fertilizers–organic and inorganic. Both have their merits and their disadvantages, and both can help improve your lawn and garden.

Organic Fertilizers

“Organic” in this context is different from organic foods. In chemistry, “organic” refers to materials derived from carbon-based sources, aka plant or animal matter like compost, manure, or bone meal.

Pros:

• Organic fertilizers provide a constant nutrient supply as microorganisms like earthworms, bacteria, and fungi decompose the materials.
• They only need to be applied twice a year at the beginning of each growing season: mid-September and late February.
• These fertilizers feed beneficial microbes and improves soil quality over time.
• They contain nutrients in low concentrations, therefore are unlikely to cause chemical imbalances in the soil.

Cons:

• Nutrient release is slow; if your plants have a nutrient deficiency that requires immediate correction, organic fertilizers may not address the issue quickly enough.
• Without laboratory testing it is impossible to know exact concentrations and nutrients the fertilizer contains. This makes it difficult to address specific issues in your garden.
• Unless you create your own compost, organic fertilizers are relatively expensive; a larger volume of organic fertilizer is required because of lower nutrient concentrations.
• If using manure, be sure it is fully decomposed before applying. Non-composted manure can harm plants due to high salt concentrations.

Inorganic Fertilizers

Inorganic fertilizers have gone through processing to isolate specific nutrients. They contain specific ratios of nitrogen, phosphorus, and potassium along with other micronutrients.

Pros: 

• Inorganic fertilizers provide instant access to nutrients.
  In nature (and organic fertilizers), nutrients exist primarily in forms that plants cannot uptake until converted by microorganisms. Inorganic fertilizers contain nutrients in forms plants can uptake immediately.
• Each bag contains a specific nutrient ratio, so you know exactly how much you are applying.
• Purchasing a fertilizer with a specific nutrient allows you to fix a deficiency without causing an excess of unneeded nutrients.
• Because of their high nutrient concentrations, a little goes a long way and thus they are less expensive than organic fertilizers.

Cons:

• The nutrients are not bound to the soil or other materials, meaning they leach out (or move through the soil) quickly. Some nutrients are lost before the plants can use them.
• Inorganic fertilizers need more constant application than organic fertilizer.
• Because of the higher nutrient concentrations, you can accidentally apply too much and chemically burn your plants.
• Overapplication can cause toxic buildup of salts and chemical imbalances in the soil.

Is There a Right Choice?

Many factors go into your decision when choosing a fertilizer. In the long-term, organic fertilizers will improve your soil and provide constant access to nutrients. However, if you’ve identified that your plants need a specific nutrient or if you want to jump-start an area at the beginning of a season, adding an inorganic fertilizer may be the right option. Visit our shop for all your organic and inorganic fertilizing needs, including fertilizers for specific varieties of plants.