Greenhouse growing is similar to growing outside except it gives added control and the option for continuous high quality results. One of the big differences between a plant growing in its natural habitat and one growing in a artificial habitat can be its soil. Healthy soil is key in strong plant grown, but what defines healthy soil? It is a combination of biological, chemical, and physical properties that when working together can function as a vital living ecosystem to sustain plant growth. In order to reach high quality soil in your greenhouse it helps to know about these properties and how they work.
Though there may be some harmful biological organisms for your plants, if good organisms are present in your soil they can help aggregate soil particles, cycle nutrients, transform nutrients, and assist the plants in obtaining those nutrients. They can also degrade any toxic substances to minimize disease in plants. In addition, they can improve the porosity of the soil resulting in better water penetration to the plant’s roots. The chemistry of soil is concerned with the availability of chemical elements such as nutrients which are essential for plant growth. The availability of these elements for plant uptake is affected by soil pH and reactions of the elements with soil particles and organic matter.
Physical soil characteristics like soil texture and structure effect soil health. Soil texture (sand, silt, clay particles, etc) is important because it plays a role in the porosity of the soil and final soil structure. Soil structure can effect root penetration, water absorption, nutrients and air, and also assist the growth of microorganisms. There are two types of non-structured soil and four main types of structured soil:
- Granular – Sand, high permeability.
- Massive- Clay, limited permeability.
- Crumb structure – Easily crumbles in your hand meaning soil is porous and permeable. It can also retain moisture making it the most ideal soil structure.
- Prismatic structure – Forms columns with flat tops separated by deep cracks. Permeability varies depending on cracks and columns.
- Blocky structure – Blocky and moderately permeable.
- Platy structure – Flat horizontal soil that is almost sealed. Drainage and permeability are poor. Least ideal soil structure.
Organic matter (left image) is anything that contains carbon compounds that were formed by living organisms. This can be achieved through many different types of additions to your soil; lawn clippings, leaves, stems, branches, moss, algae, manure, droppings, sewage sludge, sawdust, insects, earthworms and microbes to name a few. There are three main components of organic matter in soils; dead forms (mostly dead plant parts), living parts of plants (mostly roots), and living soil animals/microbes (worms/bacteria). Adding organic matter to soil helps supply the plants with nutrients as well as help improve the soil structure, organisms, and bind soil pollutants.
So what does soil health have to do with your greenhouse? Well, setting yourself up with a top of the line greenhouse is only half of the battle. Considering that most greenhouse crops are often planted in pots or beds with fertilizer and bottled nutrients, the soil can lose most of its organic substance and the plants can suffer. Understanding the biological, chemical, and physical properties that effect soil can help determine what actions need to be taken if you want to improve your plant’s soil health.
My next post is going to continue on the topic of soil by introducing the conversation of no-till gardening. This can provide some of the highest quality soil for your crops.
Do you have any experience with this topic? What type of organic matter do you use in your soil? Please leave your thoughts in the comment section below.