Good gardening begins with good soil. A successful gardener needs a basic understanding of soil, as soil conditions strongly influence how plants grow. Healthy soil is a living system filled with beneficial bacteria, fungi, and small organisms. These organisms break down rock, plant, and animal matter, releasing nutrients in forms that plants can absorb.
Understanding these components helps gardeners create healthier soil and stronger plants. Gardeners working with containers or balcony setups can also explore our Growing Media for well-balanced potting mixes.
Three different soil particles determine a soil’s texture. Sand particles are the largest, clay the smallest, and silt is in between. Medium-textured soils (loam, sandy loam, and silt loam) have a good mixture of sand, silt, and clay that is ideal for growing most plants. It is more difficult to grow plants in soils that contain an excessive amount of either clay, sand, or silt.
The easiest way to evaluate your soil’s texture is to lightly squeeze a handful of moist soil. If the clump crumbles apart, the soil is sandy. If it forms a sticky ball, it is clay. If the soil ends up as a spongy ball, you have loam.
The combination of individual sand, silt, and clay particles into larger clumps called aggregates creates soil structure. Good garden soil is crumbly. Nutrients and water are held within the aggregates, while the spaces between them allow water and air to move easily through the soil and provide enough room for plant roots to grow.
Plants grow best when good soil structure is maintained. Avoid walking on, working in, or driving machinery over wet soil. It is also important to refrain from excessive tilling, as these actions can damage soil structure and compact the pores, reducing the movement of air and water.
Amendments are materials that change the physical or chemical properties of the soil and indirectly improve plant growth. Reasons to amend soil include improving water permeability, enlarging pore spaces, preventing cracking, making soil easier to work, and helping roots transition from container soil into heavier native soil.
A variety of amendments
Soil organic matter consists of all the dead plant and animal material in various stages of decay. A soil rich in organic matter supports a thriving population of beneficial organisms, from microscopic bacteria and fungi to earthworms. Organic matter acts like a slow-release fertilizer and improves soil structure. Soil microorganisms feed on organic matter and release nutrients in forms that roots can absorb.
Compost is an excellent organic amendment. You can explore natural compost-based options like our Bio Farm Organic Fertilizer, which supports soil health and microbial activity.
For improving soil structure and water retention, a soil conditioner such as Active Silicon Soil Conditioner can be helpful in certain garden soils.
The top six to eight inches of garden soil should be amended with composted organic matter. If you spread two inches of compost on top of previously cultivated soil and incorporate it to a depth of six inches, the soil will be amended by about 25 percent by volume.
If you're preparing fresh potting mixes, explore our Growing Media collection for ready-to-use blends.
Organic matter continually breaks down and decomposes, so gardeners must periodically add new material. Good gardeners incorporate organic matter into their soil before each planting season.
Vegetables and flowers usually grow better if fertilizer containing nitrogen, phosphorus, and potassium is mixed into the soil prior to planting. Organic fertilizers are derived from plant, animal, and mineral sources. They feed microorganisms in the soil, which break down the organic matter and release nutrients in forms that plant roots can absorb.
The advantage of organic fertilizers is that they contain multiple nutrients released slowly over time, making them available to plants for longer periods. They are less likely to burn plants or be lost from the soil and may also act as soil amendments.
Prior to planting, apply fertilizer uniformly over the soil and till it in to a depth of about six inches. During the growing season, most plants will periodically need additional nitrogen. Apply nitrogen fertilizer when direct-seeded crops have four to six true leaves, and for transplants, about four to five weeks after planting.
Additional applications may be needed every four to six weeks depending on the crop. In sandy soils requiring frequent irrigation, smaller amounts applied more often are recommended.
Browse plant-safe options in our Organic Fertilizers range.
Soil acidity or alkalinity is expressed as a pH number ranging from 1.0 (extremely acidic) to 14.0 (extremely alkaline). A pH of 7.0 is neutral. Most plants grow best in slightly acidic to neutral soil (pH 6.0 to 7.0).
Many cultivated soils tend to be alkaline because irrigation water is often alkaline. Soil pH affects the chemical form of nutrients like phosphorus and iron. When pH is too high or too low, plants may suffer nutrient deficiencies even in nutrient-rich soil.
Soil testing provides information on soil texture, pH, salinity, and nutrient levels. This is especially useful when starting a new garden or diagnosing poor plant growth. A soil test will not identify issues caused by pests, diseases, improper irrigation, or poor cultural practices.
One of the most useful soil tests measures pH. A lab can test soil pH for you, or you can use a simple pH meter or test kit. Basic tools that support soil preparation can be found in our Tools & Equipment collection.
To collect a good soil sample, dig a small hole 6–8 inches deep and take a thin slice of soil from one side. Repeat this in several locations, mix the samples in a bucket, and send a representative sample to the lab. Ask if the lab provides interpretation and recommendations.
