SIMPLE DEFINITIONS OF COMMON GARDEN TERMS
A lot of the time in the gardening community words and phrases are used with the assumption that those reading/consuming the content have a certain level of knowledge of gardening terms. If however you're new to gardening then you may very well not yet have that knowledge and it can be confusing and frustrating to not understand what certain things mean. This is a great shame because it might put you off getting involved in the gardening world for fear of it being too complicated or a sense of being excluded.
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So I wanted to write this simple guide to gardening terminology (which I'll add to over time) to give beginners to, or even those more well versed in, the gardening space a resource to demystify and clarify common terms
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There is also the persistent issue that not everyone (including plant and soil scientists) can actually firmly agree on what a lot of terms mean so you will often see contradictory definitions. I am writing my definitions with the aim of providing a useful way of understanding these terms and what people in the gardening world tend to mean by them, appreciating that even my definitions may conflict with others!
Let's get into it!
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Compost/mulch - I've included these two together because they are often used interchangeably and so can be a little confusing. Simply put, both terms refer to decomposing organic matter, they just represent different degrees of decomposition. Compost refers is organic material that has broken down far enough that it has become the dark, crumbly substance that you'll see in compost heaps and in bags at garden centers. Mulch refers to organic matter that has not decomposed to this state and still looks broadly like the organic material it started out as. Mulch can also refer to a host of different materials like wood chip, partially decomposed leaves, grass cuttings, even cardboard! Literally any organic material that hasn't decomposed down into compost, could be considered a mulch. Mulches are generally used as a protective layer over soil to help keep water in the soil and to prevent weeds.
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Fertile - almost always used to describe soil. This simply means soil with a lot of beneficial nutrients in it like nitrogen, phosphorus, magnesium, potassium etc. A gardener can make their soil more fertile by applying compost/mulch to the soil regularly (once or twice a year depending on the existing quality of the soil) as these consist of decomposing organic material whose nutrients are released into the soil as the decomposition continues.
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Greens/Browns - Generally used when discussing making compost. Greens refers to nitrogen rich material like freshly cut grass, plants etc and browns refer to carbon rich material like older, dry leaves, paper, cardboard etc. This is slightly simplistic as sometimes things you would think are 'greens' are actually carbon rich and vice versa but as a general rule this holds up.
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Humus - Humus is another term that is often used interchangeably with compost but they are not the same thing (there is even some research suggesting that humus as we previously understood it doesn't actually exist! For the purposes of this guide however I'll define what people usually mean by the term). Like compost/mulch discussed above, humus is once again decomposed organic material but it represents organic material in pretty much its most advanced state of decomposition, i.e. the organic material won't decompose any more than it has. Adding compost to your garden will eventually lead to more humus in the soil as the compost continues to break down. Humus is good for soil because it holds lots of moisture and improves soil quality (not too dry, not too wet and clay-like, loose enough for plant roots to make their way through).
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Loam - Loam, or loam soil, is type of soil rather than a distinct entity itself. It refers to soil that is a healthy combination of sand, silt and clay. Loam soil is crumbly but holds water well whilst also being well draining. Adding organic matter to your soil via compost or mulch can help make your soil more loamy over time. It is not a quick process rather a long-term process of slowly increasing soil quality.
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Organic Material - When people use this term they are generally referring to dead plants, bits of plants, leaves, twigs, wood chip etc. Essentially anything that used to be or came from a plant and is usually used in the context of improving soil health by adding compost/mulch to the soil. The term does also technically include anything that used to be alive so can include dead animals (though we don't recommend mulching your garden with dead animals!), other food stuffs and cardboard/paper which in particular can form a very useful part of your own compost by adding carbon rich material to the compost heap.
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Well-draining - when gardeners describe soil as 'well-draining' it tends to mean soil with a good amount or organic matter in it. This creates a soil through which water can easily pass, further down into the ground rather than a soil that traps water higher up leading to very wet or clay-like soil that can drown or cause rot in your plant roots.