Soil Overview

Soil types are primarily distinguished first in terms of “texture”. Soil is basically made up of pieces of rock, believe it or not. The basic components of soil are either large pieces of rock – sand – or much smaller pieces – clay. For example, the largest particles, sand, determine aeration and drainage characteristics, while the tiniest, sub-microscopic clay particles, are chemically active, binding with water and plant nutrients. The ratio of these sizes determines soil type: clay, loam, clay-loam, sandy-loam, silt loam and so on. In addition to the mineral composition of soil, humus (organic material) also plays a crucial role in soil characteristics and fertility for plant life. Soil may be mixed with larger aggregate, such as pebbles or gravel. Not all types of soil are permeable, such as pure clay, which is to say it will not drain and is a stiff, root-aversive soil structure.

An ideal soil in the sense of density is one that is not so permeable that water just runs straight through it, like sandy soils do. Nor is it the clay soils that don’t even let water perk through it at all, trapping water and souring soil. So what we look for is a soil that allows drainage yet still retains some water for roots to have more consistent access over a longer period of feeding. Structurally, the soil needs to be able to support the growth and development of taller plants by letting roots go deep enough and wide enough to supply a base.

Mixed in with these two characteristics we address organic material, or “compost” as it is commonly known. A compost able material like a wood product or even older roots left from earlier plantings form a thriving culture of constantly evolving bacteria who serve to “break down” the composition of the organic material and provide necessary chemical ingredients, most importantly nitrogen. A multitude of other sources for this compost is available in household garbage and in food wastes, among other things. Mixed in as deeply as possible with soil, this gardening chore really is the most effective way imaginable for developing a healthy garden.

Compost is one of nature's best mulches and soil amendments, and you can use it instead of commercial fertilizers. Best of all, compost is cheap. You can make it without spending a cent. Using compost improves soil structure, texture, and aeration and increases the soil's water-holding capacity. Compost loosens clay soils and helps sandy soils retain water. Adding compost improves soil fertility and stimulates healthy root development in plants. The organic matter provided in compost provides food for microorganisms, which keeps the soil in a healthy, balanced condition. Nitrogen, potassium, and phosphorus will be produced naturally by the feeding of microorganisms, so few if any soil amendments will need to be added. A well-composted soil will need far less fertilizing, less watering and will develop strong roots for the stability of upright flowers and plants.