How and What Plants Eat
From Chapter 16 of "Healthy Garden Healthy You" by Milo Shammas
Plants consume their food primarily through their roots, and the majority of the nutrients are absorbed through microscopic root hairs. This is why a great soil structure is so imperative; it gives the roots regular access to the needed nutrients in a soil that is heavily laden with organic materials. Root hairs also ensure a slow and steady supply of all needed nutrients on a regular basis for all fruits and vegetables.
The perfect formula for root expansion combines a well-constructed loamy soil with balanced pH, soil that can breathe with plenty of air space, organic humus reserves, microbial diversity and activity, mycorrhizal proliferation and spongy organic soil particles for water retention. Microbes help break down organic matter into forms of nutrients that plants can absorb and use for growth. The living portion of the soil, the probiotics, makes the nutrients available consistently all the time, especially when plants can use them the most. This is usually temperature related. The warmer the weather, the more nutrients a plant needs. In warmer weather, microbes are more active in the soil, releasing the needed nutrients from the organic materials.
When nutrients are stored in and on soil particles, they are conserved for plant roots to use as needed, rather than leeching through the soil to the ground water where they cannot be absorbed by the microscopic root hairs. The greater the soil capacity to store nutrients, the more the roots can feed as needed. As the roots burrow wider and deeper, they absorb more nutrients, which allows plants to grow and produce more fruits and vegetables. The cycle becomes self-perpetuating: better soil, more root mass, larger plants, more absorbed nutrients, producing healthier, nutrient-dense fruits and vegetables.
How and What Do Roots Consume?
Plants retrieve nutrients mainly from water within the soil. Eroding rock and degrading organic matter also make nutrients available in the soil. Microbes decompose organic material but roots do not directly consume microbes, just the nutrients that microbes leave behind. Imagine "microscopic manure" as plant food.
Plants need all the nutrients discussed in our previous post titled Essential Micronutrients. They are absorbed from soil, air and water. Plants use each mineral along with carbon and hydrogen to synthesize compounds such as phytonutrients, vitamins and anti-oxidants. These compounds perform many functions within each plant that help provide structural support, transport fluid, nutrients and assist in metabolism of absorbed food. In general, plants consume macronutrients in large quantities to form root, stem and leaf cells.
Rocks and humus reserves contain micronutrients. Micronutrients support metabolic processes like photosynthesis and the uptake and processing of other nutrients by the plant. Micronutrients are just as important as macronutrients and insure plant processes run smoothly. They support many different functions including proper chlorophyll formation, which affects photosynthesis, which is crucial for activating enzymes and forming hormones. Micronutrients also aid vitamin formation, regulate metabolism and cell growth, promote the efficient use of nitrogen and thus protein formation, and simply allow plant cells to engage in photosynthesis.
Depending on the plant species and the micronutrient, a lack or surplus in one of these nutrients can cause major development problems and in some cases death. For instance, a boron deficiency is a make or break situation. By the time one can see the deficiency, it is too late. Also, over applying these micronutrients can poison plants, since they are needed only in very small quantities. Sometimes deficiencies can go undetected by the human eye, while something inside the plant is not properly functioning. For example, the plant cell wall may be too thin to protect it. This causes a plant to be more susceptible to pests or disease. If a plant is deficient in any of the essential micronutrients for a long period, noticeable symptoms develop.
Manually applying micronutrients to the soil may be a mistake given our limited knowledge of how micronutrients affect plants. As their name implies, micronutrients are needed only in minute amounts. They promote optimum growth only in a small range. For example, the range in which boron is either deficient or over-concentrated and toxic is only a few parts per million. For this reason, safely applying boron requires precision beyond the average gardener's abilities. In addition, even a small excess in one micronutrient can cause a deficiency in another, since these elements interact.
Macronutrients are needed in larger quantities. Introducing too much of a macronutrient through over fertilization can create deficiencies in micronutrients. For example, too much potassium leads to too little manganese absorption. Managing all the hazards is difficult. Fortunately, there are ways you can work around these hazards.
Little Things Matter
Micronutrients may be more important for healthy, strong, pest- and disease-resistant plant development than the major N-P-K nutrients receiving the most attention in recent decades. Raw organic material contains a variety of micronutrients that can be preserved naturally in the soil. Organic matter contains molecules that electromagnetically "grip" the nutrients and prevent them from leaching through the soil and beyond the reach of plants. I stress the importance of micronutrients in the soil, because they are the building blocks for healthy plant material.
Research on these beneficial phytonutrients is still in its infancy, but some evidence points toward health benefits. Industrially processing freshly harvested plants probably causes us to lose many phytochemicals and their potentially beneficial effects, such as resistance to disease. Processing is like cooking the nutrients right out of fruits and vegetables. We know that the more we alter anything from its natural state, the less nourishment it gives us. For this reason, doctors recommend eating plenty of raw salad.
Plants contain more vitamins, minerals and phytochemicals than one supplement can contain. Because nutrition is a relatively new science, researchers are still unsure which nutrients, plant compounds and ratios work best. The content and balance needs also differ between men and women. Supplementing will not fully compensate for lacking a well-balanced diet of many different fruits, vegetables, carbohydrates and proteins. Even if you grow and consume as many fruits and vegetables as you can, you may still want to supplement with a well-rounded "bioavailable" multivitamin for extra protection. I do. The essence of growing a healthy garden is to maximize the nutrient density in those foods, but we live in a polluted world. If you ever eat out or travel, you will never be able to grow every ounce of food you eat.
Milo Lou Shammas
Founder and Formulator