Cultivate Brilliance: Mastering the 4 R’s for a lush, thriving garden

Purpose of Fertilizers

Fertilizers are available in various formulations. There are two primary classes: organic (or natural) fertilizers and inorganic (or synthetic) fertilizers. An interesting aspect of these different classes is that both are beneficial to your garden if applied, according to the 4 R’s of fertilizing which are the right source, the right rate, the right time and right place.

The first step is to assess the current soil fertility of the garden. A soil test provides quick and accurate information about the soil’s pH and the concentration of nutrients in your soil profile. When you send soil samples to a lab, you typically receive recommendation on which nutrients to add for optimal productivity in the upcoming growing season. This information is essential to ensure the correct amount of fertilizer is applied and avoid issues such as excessive new growth and promote healthy productive plants.

Essential Nutrients for Plant Growth

Fertilizers are substances added to the soil to increase its fertility. They consist of chemical elements or compounds that are essential to plant growth. There are 17 essential nutrients for plant growth which can be divided into macronutrients and micronutrients. Macronutrients such as nitrogen, phosphorus, potassium … are required in large quantities while micronutrients like iron, zinc, nickel… are required in small amounts.

Natural vs. Synthetic Fertilizers

Fertilizers can be grouped into two classes based on the source of their nutrients. Organic (or natural) fertilizers are derived from animal and plant matter, whereas inorganic (or synthetic) fertilizers are mined or manufactured.

Natural (Organic) Fertilizers

Organic fertilizers come from decomposing animal or plant material and consist of humus-like substances that have not completely decomposed. Soil microbes break down these materials, releasing nutrients in forms that are available to plants. As temperature and moisture increase, the microbial activity intensifies, resulting in greater nutrient release. For example, cow manure may only release about 25% of its total nutrients during the first season. For this reason, you might need to supplement with other forms of fertilizers if the nutrient demands during the growing season are high.

Synthetic (Inorganic) Fertilizers

Synthetic Fertilizers are primarily derived from non-living sources such as mineral deposits. For example, phosphorus, one of the primary macronutrients, is typically mined from phosphate rock. These fertilizers are formulated to be water-soluble, providing rapid nutrient delivery in liquid or granular forms. Some formulations even coat the water-soluble fertilizers with materials that extend the nutrient release. Compared to natural fertilizers, synthetic fertilizers differ primarily in the timing of nutrient availability; some are designed for slow or controlled release.

Creating your Garden Fertilization Game Plan

The first step in implementing a fertilizing strategy is to begin with a representative soil test. This involves taking multiple samples from various, random parts of your garden to obtain an average measure of nutrient distribution. A diagnostic lab will provide recommendations on sampling procedures and nutrient additions based on your soil fertility results. You can also contact your local Extension office for more information about sampling and nearby soil analysis laboratories. At-home soil testing kits are available at greenhouse, gardening stores, as well as many agricultural supply stores.

Next, select fertilizers based on your garden’s soil needs. Organic fertilizers provide long-term improvements in soil fertility and overall soil health while synthetic fertilizers offer rapid nutrient delivery during the growing season. Consider blending both types of fertilizers to meet your plants’ demands throughout the season. It is important to meet nutrient requirements without over-applying, as close as possible. Organic and synthetic nutrients can burn your plants and reduce crop yields.

Applying fertilizers according to the 4R’s provides a framework to ensure you are using the right source, at the right rate, at the right time, and in the right place.

Ask yourself:

• (Source): What nutrients are already available in my soil?
• (Rate): What is the plant’s nutrient demands?
• (Time): When do the plants require nutrients?
• (Place): Where will nutrients be most effectively absorbed?

Using the 4R’s as a guide combined with your soil test results and a thoughtful choice between natural and synthetic fertilizers will help ensure a healthy and productive garden.

For further information regarding fertilizing please reach out to your local Extension office.

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