Good Soil Structure is Key for Organic Gardeners

Plants must have access to thirteen mineral elements in varying amounts if they are to thrive. However, before you go throwing money away on bags of fertilizer, it pays to give attention to the soil structure. In fact most garden soils contain sufficient nutrients. Often what is missing is a good soil structure.

The Meaning of the Term Soil Structure

The term soil structure describes the way the soil is put together. It is the arrangement of the particles of weathered rock, organic matter and living organisms which make up about 50% of the soil. The rest is made up of air and water. Manage the soil badly and you can easily destroy the soil structure. Treat the soil well and you can maintain and improve the soil structure.

How Soil Structure Affects Plant Growth

Poor structure means shallow root systems, smelly soil, and poor drainage, soil which is sticky or made up of hard lumps, few worms, compacted layers and a crusty surface when the soil dries out.

Good structure ensures deep rooting of plants, sweet smelling soil, good drainage, ease of digging, no compacted layers and a crumbly, friable layer of top soil (tilth). As a result your plants have access to water, oxygen and food.

How to Improve the Soil Structure

The best way of improving soil structure is to add bulky organic matter such as garden compost, composted green waste or well-rotted farmyard manure.

Organic materials are often mistakenly regarded as fertilizers. In fact they contain far fewer nutrients than fertilizers. It is their ability to improve the physical structure of the soil thereby rendering the nutrients already present in the soil available to plants, which makes their role in plant health so vitally important.

How Bulky Organic Materials Improve the Soil Structure

• These materials break up sticky clay soils and add weight to light, sandy soils.
• They encourage a wealth of organisms to thrive in the soil, from insects and worms to bacteria and fungi, all of which help to stick tiny soil particles together forming highly desirable crumb structures.
• The air spaces in between the crumbs give the roots plenty of space to grow and breathe.
• Organic matter soaks up and releases water readily so is excellent in sandy and chalky soil which drain readily.

When and Where to Apply Bulky Organic Materials

• Organic matter can be incorporated into the top soil prior to planting.
• It can be applied as a mulch to established trees, shrubs and perennials.
• When used as a mulch in the kitchen garden it is particularly beneficial for conserving moisture around celeriac, pumpkins and squashes.

So be Generous with Organic Matter

As well as adding organic matter the application of fertilizers to supplement those nutrients held in the soil will give optimum plant growth, always provided the soil’s acidity/alkalinity level is appropriate for the plants being grown.