Fall is an important time to fertilize the garden, sometimes known as "winterizing." Shrubs, trees and plants begin to use their energy to strengthen and expand their root systems in preparation for winter dormancy and spring growth. Fall fertilizing provides a slow absorption of nutrients into soil and root systems. Nutrients provided in fall fertilizer feedings promote strong growth and increased disease resistance in spring.
Indications that shrubs and plants need fertilizer are yellowing leaves, reduced leaf size, premature fall coloration and leaf drop, reduced twig and branch growth and an overall lack of plant vigor. Younger shrubs, trees and plants need more fertilizer than established ones. Plants undergoing drought or other climate stress have increased fertilizer needs in fall.
Types of fertilizer include synthetic chemical fertilizer and fertilizer from natural sources. Synthetic chemical fertilizer is absorbed directly by plant root systems and does not sustain healthy soil functioning. Fertilizer from natural sources is absorbed by roots and provides microorganisms to soil, which enhance soil health slowly over time. Natural sources of organic fertilizers include animal manure, seaweed, cottonseed meal, feather meal, blood meal, alfalfa, mined rock posers and fish bone meal.
Fertilizer is available as granules, pellets, spikes, capsules, liquid and as decomposed compost. Consider the type of plant, the time of year, the desired rate of dispersion and cost per application when choosing a fertilizer. Synthetic chemical fertilizers may be toxic in concentrated form and create a storage problem. Children and pets should not be exposed to synthetic chemical fertilizers.
Organic fertilizer from natural sources introduces microorganisms into the soil. Organisms such as bacteria, fungi, protozoa, micro-arthropods and beneficial nematodes work within the natural cycle of growth to feed plants steadily. The organisms break down materials in the soil to make nutrients available to plants. Many microorganisms ingest harmful pathogens in the soil that would otherwise attack plants to cause disease.
Nutrient transfer to plants during the fall fertilizing process is accomplished by the beneficial bacteria in natural materials. Bacteria break down larger plant materials, then store and release them as needed. Organic fertilizer ensures a slow, steady supply of nutrients. Plants and shrubs are then able to resist the stress of disease, drought, frost and harmful insect infestation.