Nitrogen the Big N

Nitrogen is an essential plant nutrient, needed in all plant enzymes and proteins. It also forms part of chlorophyll, the pigment responsible for photosynthesis, allowing plants to absorb energy from light. At this time Nitrogen the Big N! of year when the weather warms up and plants start putting on lots of growth, it is typical to see nutrient deficiencies in your plants. The most likely nutrient to be deficient in your plants is nitrogen, as plants require it in large amounts. Nitrogen is most abundant in the air we breathe - in fact our atmosphere is 78% nitrogen gas! Many elements plants need are the so-called mineral elements found naturally occuring in soil from the parent material, that is, the rock the soil was formed on. As nitrogen does not naturally occur in the soil parent material, it can only be supplied to soil by nitrogenfixing bacteria, atmospheric deposition in rainfall, or organic materials from living organisms that contain nitrogen (plant material, manure). Nitrogen is also supplied by fertilizers. Nitrogen is a mobile nutrient within the plant. When it is in short supply the plant will move nitrogen from the old leaves to the new growth. Therefore, nitrogen deficiencies are first noticeable as a yellowing of the older plant leaves. How to add nitrogen to your soil? Rotate legume family crops through your garden to take advantage of their N-fixing Rhizobia bacteria. Add organic matter! When soil warms up in spring, microbes break down organic matter releasing nitrogen in plant-available forms ammonium and nitrate. Feeding your plants with a liquid nitrogen fertilizer is important as natural sources (organic matter, manure) often do not provide enough nitrogen for heavy feeding plants (e.g. tomatoes, squash) during the growing season. To avoid wasting fertilizer, time your liquid applications to when the plants need it the most, which is during the spring and summer when the plants are putting on the most growth. Nitrogen is highly mobile in soil, meaning plants can take advantage of it if it is there, but once it leaches below the root zone it is no longer available to the plant. The best strategy for applying fertilizer is to do small amounts frequently rather than a large amount all at once.

Tamara Dinter, Dinter Nursery General Manager and Soil Enthusiast