GreenWorks’ Approach to Soil Nutrients and Fertilization
Greenworks of CT offers fertilization programs customized for your specific soil conditions. We do this by having a soil analysis done to determine which nutrients if any are lacking or overabundant and weather your soil needs a PH adjustment. Improper fertilization can promote plant pests and hinder healthy growth. A soil analysis will also indicate what type of soil you have, this will help us determine recommended frequency of fertilization. For most soils in Connecticut we recommend 2 – 4 applications of fertilizer per year for lawns and 1 – 2 applications per year for trees and shrubs, depending on soil type and site conditions.
The 3 Primary Soil Nutrients
Out of the 12 essential soil nutrients there are 3 that are needed in abundance for plants to survive and thrive in our landscapes. These are Nitrogen(N), Phosphorus(P), and Potassium(K). Levels of Nitrogen, Phosphorus, and Potassium range dramatically in CT soils depending on soil type and soil history. These nutrients are the primary nutrients added when fertilizing soil. Commercial fertilizers are required to print the percentage of each nutrient on their package. For example a fertilizer labeled as 10-10-10 contains 10% of each of the Primary Nutrients. The first number is Nitrogen, the second is Phosphorus, and the third is potassium.
Intermediate Soil Nutrients
Out of the remaining 9 nutrients 3 of them are referred to as intermediate soil nutrients not because plants require less of these nutrients but because soils often already contain enough of these nutrients to meet the needs of landscape plants. These nutrients are Sulfur, Magnesium, and Calcium. In Connecticut these nutrients typically are present in high enough concentrations but occasionally need to be added to the soil. Primary and Intermediate nutrients are collectively called macronutrients.
The remaining 6 nutrients are called micronutrients because although they are just as important for plants they are only required in very small amounts in the soil. The micronutrients are Iron, Boron, Mangnese, Zinc, Molybdenum, and Copper. In Connecticut most of these nutrients are usually not lacking, but occasionally micronutrients such as iron may need to be added.
Fertilizers differ dramatically in application method and speed of release. Fertilizers are formulated using natural and synthetic substances. A fertilizer must be formulated into chemical compounds that are stable enough to last in the soil and are in a form that plants can take up, therefore creating exact desired percentages of nutrients is not typically possible nor is it needed. The most important thing to look at when selecting a fertilizer is the amount of the desired primary nutrients compared to the others (which primary nutrients are generally high or low in a given fertilizer). Fertilizers may often include intermediate nutrients, micronutrients, and beneficial microbes such as mycorrhizae, these are usually listed on the information label. Nitrogen is somewhat of a unique nutrient, Nitrogen levels in the soil fluctuate dramatically throughout the year and Nitrogen fertilizer often becomes unavailable to plants quickly. Slow release Nitrogen fertilizers give soil a long lasting source of Nitrogen so plants can continue to benefits for months after the fertilization.There are a number of different application methods such as granular, soil injection and others. Some application methods are better than others but which application method is best depends primarily on what type plant is being treated.