The soil is where plants are grown. It is made up of little fragments of rock broken off of mountains and other bigger rocks, together with a few pieces of extinct plant and animal life. Here, dissolved nutrients are absorbed by plant roots and transformed into the plant’s stems, leaves, flowers, and fruit.
The following article is not an exhaustive primer on incredibly complicated soils, which is the subject of many publications, studies, and entire university departments.
In contrast, this is a straightforward introduction to a crucial aspect of our landscapes. To variable degrees, three interconnected characteristics that all soil possess determine a soil’s capacity to support plant life.
3 Soil Characteristics That Affect Plants
Like individuals, soil’s personality results from synthesizing its ancestry and surroundings.
Although the various impacts are more straightforward to identify and evaluate in soil than in people, the outcome is an unpredictable blend of what was added later and what was there initially.
1.) Moisture-holding Capacity
The size of the rock particles in the soil, also known as texture or moisture-holding capacity, largely determines its moisture-holding capacity.
Clay soil contains the smallest particles and is so densely packed that little air spaces remain. Because there is a lot of surface area on so many tiny particles, and because the air gaps are so small, it is difficult for water to drain away efficiently.
Silt is a term for medium-sized particles that drain effectively while holding soil well.
Sand is the type of soil with the largest particles because the pieces fit together less tightly and have more space between them, which makes it easier for water to pass through.
The amount of organic material that is incorporated into the soil’s rock-particle mix will also impact how efficiently it drains or retains moisture.
Plants that die each year return their decaying remains to the ground, where fungi and other small creatures we never see mix them into the soil below. Examples of these include:
- Seasonal fallen leaves
- Grasses lying on the ground
- Spent flower heads
- Seed husks
- The countless plants that die every year
In addition, organic matter makes the soil more pliable, which helps clay soil release water and sandy soil hold moisture.
Home Soil Test (Using a Glass of Water)
Take a pinch of soil between your thumb and fingers, then dip it into some water to determine your soil type.
Keep your fingers together while you complete this. Then take them out of the water, rub them together, and feel what’s still inside to see how it feels.
If it is hard and gritty, your soil is primarily made of sand since the particles are large.
On the other hand, you have a lot of microscopic clay particles in your soil if it is sticky and slick.
The range of consistency between gritty and slick corresponds to different particle sizes, with silt being the most typical. Though not a precise science, you get the idea.
Pick Plants That Can Survive in Current Moisture Levels
All around the world, plants have adapted to flourish in various soil conditions, from highly moist to extremely dry.
If we choose these plants based on the type of soil in our landscapes, we will spend less time and effort watering thirsty plants and more time improving the soil’s ability to drain quickly or slowly.
In the American southwest, water is scarce and gardens are created to require less water, this is the fundamental idea behind xeriscaping (using drought-tolerant plants), which has become quite popular. However, the idea is applicable worldwide.
2.) Acidity or Alkalinity of the Soil
The type of rock primarily governs the acidity of the soil from which it was formed (its parent rock).
No matter how much the rock has been broken, split, and continuously crushed, no matter how little its particles become, this original mineral composition still exists in the soil.
The soil will be alkaline if the majority of the rock fragments in the soil are of limestone origin (often called sweet or lime).
More acidic soil originated primarily from quartz or granite.
Chemically speaking, the activity or reaction of a soil’s hydrogen ions determines how acidic it is. The pH scale from 1 to 14 denotes this measurement (pH stands for hydrogen power).
On this scale, 7 represents neutral soil, 1-6 illustrates acidic soil, and 7-14 represents alkaline soil.
What do these figures signify, though, to non-scientists? Basically, many elements crucial for plant growth don’t break down easily in acidic soils (low pH), making them unavailable to or challenging for plant roots to absorb.
In contrast, most of these critical elements become more soluble and, therefore, more available to plants in more alkaline soils (those with a higher pH).
Two articles listed below will help you adjust your soil pH:
Match Plant Selection to Current Soil pH
It’s wise to select plants adapted to the soil’s specific acidity in our own gardens and landscapes.
By doing this, we avoid the issue of adding the wrong amount of some adjustments.
We’ll save pointless journeys to the garden center and, in a perfect (or imaginative?) world, maybe even lessen the extraction of Earth’s natural resources (such as calcium, aluminum, sulfur, etc.) for the production of “soil amendments.”
3.) Fertility of Soil
The nutrients in the soil (PDF) are measured by their fertility. This comprises macronutrients like calcium, magnesium, sulfur, boron, chlorine, copper, manganese, molybdenum, and zinc and micronutrients like oxygen, carbon, hydrogen, nitrogen, phosphorus, and potassium.
Natural sources of these nutrients in soil include:
- The parent rock’s mineral composition.
- The decomposition of extinct plants and animals.
- The addition of organic matter like manure.
All soils become more fertile when worms, bugs, fungi, and bacteria are present because they break down organic materials and make them available to plants, increasing soil fertility.
Like soil acidity and moisture, plants have evolved to thrive in various soil fertility conditions—some plants, like those living in bogs or the desert, favor low-nutrient environments.
Eastern forests must be rich and fertile for their ferns and spring blooms. However, too many or incorrect nutrients may harm plants’ internal systems.
As a result, the plants may grow erratically, mature slowly, produce excessive leaves or flowers, or wither and die.
Tip: Use fertilizer only as necessary
It might be necessary to add fertilizer to garden soils that have lost the majority of their nutrients as a result of abuse, overuse, or neglect, but stable, healthy soils that are permitted to recycle their nutrients shouldn’t require it.
Not that you should never add fertilizer, mind you. Instead, if you’re unsure of the soil’s fertility, have it analyzed as a first step.
As was already said, garden centers offer this service, but the findings are only roughly accurate. Therefore, sending soil samples to a soil-testing business or agricultural extension is preferable.
If nutrients are supplied to the soil and are not rapidly taken up by plants, they will leach into the soil below and eventually end up in the water table.
The subsequent damage caused by these extra nutrients to other plants, animals, and people will require energy to mitigate and heal.
Therefore, only add fertilizer in direct reaction to a soil test, and adhere to all instructions. The ideal fertilizer has a 50% water-soluble nitrogen content that degrades slowly and prevents excessive leaching.
Choose Plants Based on Current Soil Fertility
Pick plants that can survive the natural nutrient levels of your soil to reduce the need for fertilizer.
Most garden catalogs and plant listings provide information on a plant’s growing conditions, size, and other physical characteristics.
Simply Remove Unwanted Plants
No matter what kind of landscape you have, whether it’s mostly lawn, established gardens, healthy natural areas, degraded ecosystems, or a beautiful forest, consider a radical new approach to gardening: don’t add anything.
Please be aware that doing nothing differs from adding nothing. It doesn’t advocate for irresponsible gardening.
It’s merely a suggestion to let nature add anything new as it is far more intelligent than we are at determining what can grow and survive in any given location.
Imported Soil
It frequently happens in new landscapes that the viable soil that once covered the ground has been removed, moved around, reshaped, or entirely replaced by dirt from somewhere else.
As a result, the soil in garden beds has entirely different properties than the native soil. Therefore, be sure to consider the qualities of all the various soils in your landscape when choosing plants.
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Davin is a jack-of-all-trades but has professional training and experience in various home and garden subjects. He leans on other experts when needed and edits and fact-checks all articles.