Composting: Optimize Your Soil

Yesterday was that perfect day of spring that all gardeners spend their winters dreaming about.  After a particularly long and bitterly cold winter, followed by a snow-filled spring, the sunny, yesterday's 70F weather beckoned me outdoors to work in my garden.  I had already cleaned up most of my beds.  There was some light weeding to do (I don't know about you, but there is ALWAYS weeding to do in my garden!). But my main goal yesterday was to side-dress my perennials with compost.

The foundation bed along my front walk, top dressed

Adding compost to your garden beds is the #1 best thing you, as a gardener, can do to improve your soil.  Compost, by the definition found in Merriam Webster Dictionary, is "a mixture that consists largely of decayed organic matter and is used for fertilizing and conditioning land."  It is a simple and straightforward definition, but I find that gardeners have a lot of questions and concerns about which compost is best, how and when to apply it, and how to make their own compost.  Before we get to that, though, let's look a little deeper at how and why compost is so beneficial to your soil.

Soil is something that, in and of itself, we often take for granted.  We may vaguely know we should add various amendments to it, but we seldom think about how soil functions, and how or why something like compost is beneficial to it. Soil may be defined as the upper layer of the earth's mantle which may be dug or plowed and in which plants grow.  In other words, soil consists of tiny particles of worn and eroded rock upon which it lies.  While soil contains minerals, it does not inherently contain any of the organic matter that creates a rich growing medium. But, when decaying organic matter is placed in or on top of the soil, the creatures that live within the soil quickly go to work to break it down and incorporate it.  This material becomes humus, and it's properties allow the soil to bind together in healthy ways, to hold water, and to unlock and make available to plant roots vital minerals needed for healthy photosynthesis.

Compost is the term we use for decaying organic material.  Compost may be made up of kitchen scraps and old leaves, or it may be a manure pile behind the horse stable.  Anything that was once alive and now is decaying can be qualified as compost.  As for me, I have a couple of ways that I get and use compost.  For my flower beds and my shrubs, I go to our Village Public Works yard with a bunch of empty buckets.  There, they offer free aged compost that incorporates manure from the town horse stable, and clippings collected from Public Works projects, like hedge trimmings and dead plant materials from last year's planters, old beds, grass clippings, etc.  I can shovel and take away as much as I like, and with a couple of car loads, I can dress all my beds with this excellent free compost.

However, in my vegetable garden, I like to be a little more particular.  I like to grow my vegetables organically, and to ensure I am doing that, I make my own compost in one of the small, plastic home composters that are available to purchase at your local garden center or in catalogs.  This has benefits and drawbacks, which I'll get to in a bit.  But for right now, I want to highlight the main benefit--unlike any other compost, this method allows me to have complete control over what goes in to this compost, and ultimately, into the plot on which I grow our vegetables.  For example, when I add grass clipping from my own yard, I do it with confidence, because we do not treat our lawn with chemicals.  I cannot know for certain what is in compost I obtain from any other source.

Of course, compost is commercially available in bags at your local garden center.  You can buy anything from simple bagged manure to extra-pricey organic compost or mushroom compost.  There is nothing wrong with buying it, and any and all of it is beneficial to your soil.  Unless you are concerned, like me, about it being organic, you don't have to choose the pricey mushroom compost over the cheaper bagged manure.  In fact, it is important to be aware that mushroom compost can be high in salts, and those salts can build up in the soil over time.  This just illustrates that the most expensive option isn't always the best option.  Since compost near me is so easily obtained for free, I feel like I'm wasting my money if I buy it bagged.  It's a little more work, but I have the time and energy to do it.  The convenience and time-saving benefits of commercially-prepared bagged compost are a great option for many gardeners.

My compost bin, with a bale of straw in front

 If you are interested in composting yourself, you can make it as complex or simple an operation as you like.  You can bury your kitchen scraps in the garden-that's as simple as it gets.  Or you can build yourself the ultimate 3-stage compost bin, 9' long by 3' wide.  Or you can fall somewhere in between those two ends of the compost scale.  There are 2 main methods of composting, hot composting or cold composting. I should also mention worm composting, also called vermicomposting, which I have tried, but find somewhat impractical to maintain on a large enough scale to make it beneficial for me.


Cold composting is what I do in my bin.  You simply add your organic materials and let them do their decaying on their own time.  I generally add alternate layers of "green" kitchen scraps or any other fresh organic material, with a layer of "brown" straw, dead chopped leaves, or sawdust.  Every so often I turn my pile to make sure it has air circulation, and check it to make sure it's moist so that the materials decay rather than dehydrate.  It may take a little longer to produce compost, but that's ok with me.  It's an easy, no-fuss method of composting, and suits my style of gardening.  Since I only use my homemade compost on one area of my yard, my vegetable garden, I'm not worried about volume or how fast it is produced.

I collect my kitchen scraps in this ceramic pail.

Hot composting is a little more involved process, in which the composting occurs more rapidly and thereby  generates heat.  It can generate high-quality, weed-free compost in a relatively short period of time, but it does require a little more attention.  It uses the same materials as cold composting, and the same ratios, but just in a larger, more managed pile.  A hot compost pile generally needs to be a minimum of a cubic yard in size in order to have enough mass to maintain the heat required to cook the compost.  Most commercially available plastic composters, like the one I have, are really too small to make an effective hot compost pile, although I have no doubt that there are times where the process accelerates enough to generate hot compost conditions for short periods of time. However, they just are too small to maintain the mass needed to sustain that reaction for long.  The benefit of hot composting over cold composting is that hot composting will kill any weed seeds incorporated into the pile.  Cold composting will not do that.  Something to be aware of when adding material to your pile. When I have a weed that has gone to seed in my yard, I try to keep it out of the compost pile.  I use straw as my brown material, rather than hay, which contains thousands of seeds.
If you are incorporating cow, horse, or chicken manure into your compost pile, you should probably aim to have a hot compost pile to kill any potentially trouble-causing ingredients--whether that is weed seeds or salmonella.

Veronica 'Waterperry Blue,' side dressed with compost

As a gardener, you can add compost to your garden in two ways.  You should definitely incorporate it into the soil each and every time you dig a hole in your garden.  But, for established beds, you may simply side-dress your plants with compost.  The earthworms and other organisms within the soil will come to the surface and bring it down in to the soil naturally over time.  In fact, a good example of this is to consider a bed that you mulched last spring. If that mulch was laid directly on the soil, then the depth of it today is considerable less than it was when you first laid it.  That is because, as it decomposed, our friendly little soil-dwellers have been busy incorporating it into the soil.  Cold composting at it's finest.

Compost is a vital part of maintaining healthy, vibrant soil and keeping our plants happy and productive. It need not be intimidating, nor expensive.  If there is one thing you would add to your gardening chore list, I would encourage you to consider adding compost.  You can't go wrong!