Chaos in the Garden: Early Soil...Improving clay soil with compost

My new yard is what some people call xeriscape (pronounced ze ra’ scape). Those who understand the concept of planting in water-use zones call my gravel zeroscape. My plan is to get rid of the rock and do a better xeriscape.

I will talk about the wonderful science of xeriscaping later. Planting for low water use can be beautiful and is certainly more critical now than ever in drought affected areas

I needed to redo my whole yard. What I moved into was clay that that is as slick as snot when it gets wet, builds up on the bottom of your shoe and adds inches to your height, and so fine when it is dry that you cannot get it out of your house if you track it in. And when it is bone dry, it develops big cracks and becomes like rock. I could probably make bricks out of it.

Think of the Devils Tower, in Devils Tower National Monument in northern WY, central star of the movie Close Encounter of the 3^rd Kind and that is my soil in summer. Pictures from [1], Fine Art America [2].

The turf grass in the front was an early HOA requirement and the original owner of this house was not a gardener. During my first summer, I learned that the sod had been thrown down on the post-construction, compacted soil. There was no loosening of the ground, no addition of soil improvements, and no irrigation, so she must have watered it by hand every day to keep it growing.

There were hybrid roses at the four corners of the grass area planted in shiny rock that reflected a huge amount of sun and heat during mid-summer. And they were planted in a hole that must have been just big enough for the root ball. Needless to say, they weren’t happy. I am not a rose fan, they take a lot of work and they are mean, with their sharp thorns. So it was no hardship to dig those babies up in my first days of ownership. In the 8 or so years since they were put in, their poor roots had barely grown out of the “clay pot” hole that they had been planted into.

Because I had a limited, though largely undefined budget, I had to prioritize what was most important and worth the bigger chunks of my money. Of course, soil preparation is and should be first on anybody's list who lives in an area with less than Midwestern soil. (Yes, I am soooo jealous. There is probably clay soil somewhere in there, but what I have seen is rich, dark and full of organic matter). Soil is a complicated thing and I will talk more about soil in later blogs.

As I dug the out the roses, I learned about my new soil:

It had less organic matter in it than I thought, and organic matter is critical to the success of growing plants. Even on this lousy soil there is usually an organic layer. But not in this yard. Apparently the contractor who built the neighborhood scraped all of the meager topsoil and put it into a big pile on the edge of the subdivision. It is now a sledding hill for children - not that I begrudge them a sledding hill but I would really rather have even that bit of topsoil back on my lot.

First I had to remove the gravel. I offered it for free on Craigslist to see if someone wanted it and would haul it away. Two people answered and left with very small amounts. The shoveling and lifting was not worth it, even as a freebie. I hired a landscape contractor to remove it for a large portion of my landscape money. But as I watched his hard-working men lift and wheelbarrow that rock off my property in the hot sun, I knew I had gotten a fair deal. My contractor was a lovely man and told me with a smile that he had many jobs putting gravel down and many jobs removing it.

For organic matter, I purchased the amount of compost that my landscape contractor told me for my yard. This volume varies by soil type and if you check with folks in the landscape industry or nurseries in your area, you will find out how much is recommended. Be aware that a layer of organic matter that is too deep will slow down plant growth, so don’t think that more is always better.

I bought my compost from a company that collects green waste (like grass clippings and branches) from landscapers, grinds it up into fine bits, sprays it with water periodically (which is required in our dryness) and lets it sit in big piles for a season to begin decomposition for the composting process.

During this composting process, there is a lot of heat generated and you can see steam rising off of the piles.

This heat, plus time, is what kills most of the seed that was in the mix of green waste. This natural compost is not superheated by controlled artificial means, so in truth, most compost like this will bring seeds of some sort into your yard. But if the compost is heated artificially, all the microorganisms growing during the composting process are also killed. These microorganisms, fungi and tiny creatures are a critical component of soil improvement.

Many municipalities have a similar program of recycling of green waste. Just be aware that if the compost did not sit in the decomposing process long enough, you can bring more than a few kinds of seed into your garden. My advice - buy from a reputable source and pay the extra money.

There are alternatives like bark fines, worm castings or other products your area might produce. But keep in mind the need for soil microorganisms to help start the soil building.

Once the compost, which was rich and brown, was deeply tilled into my ground, I became a happy camper because I knew that soon I would be able to plant.