Dealing with Clay Soil

If you are reading this article for gardening ideas in and around Franklin County Virginia, you just might have clay soil in your yard.  Around me it is commonly referred to as “Franklin County Red”.   While you can’t change the soil you garden in, you can improve it and even by-pass it depending on your needs.

 Clay soil can be hard to work. It has slow drainage so it can become excessively wet, but when dry it can have the look and texture of concrete!  There are tests to determine if you have clay, but you probably already know.  However, its characteristics also allow it to retain many nutrients.   All soils are made up of particles of varying sizes and textures.  The Virginia Cooperative Extension defines clay as having: “…smallest particles that are sticky and slick when wet, and extremely smooth like talcum powder when dry; cannot be seen without the aid of a very powerful microscope”.  It is dense soil, and most plants require a certain amount of air circulation at their roots in order to thrive. 

The first thing you should do is have your soil tested.  Not all clay is created equal, and it can run the gamut with regard to pH and nutrient make-up.  There are do-it-yourself test kits available at most garden stores, but these won’t give you all the information and analysis you need.  Your local extension office will provide a box and detailed instructions to send a soil sample to Virginia Tech for a complete report on your soil for a small fee.  The report you receive will also let you know what nutrients may be lacking, and what you can do to correct this.

With clay, one solution is to amend the soil with additional material, but NOT with sand.  Clay + Sand = Concrete.  And peat moss holds water, so you probably don’t want that. The best additive is composted organic material which will lighten and loosen the soil over time and develop a good soil structure.  This is not an overnight fix, but it does work.  I have used gypsum in my soil (along with other compost) and it has worked well.  Compost and Humus can be purchased by the bag at most garden centers and “big box” stores if you do not have a compost pile.  Mix compost with native soil in your planting holes, and dig in around existing plants. Another way to add nutrients is to mulch or shred your leaves in the fall and spread them on your garden when you put it to bed for the winter.

A fast way to plant, that will also improve your soil over time, is to use berms.  A berm is an earthen embankment without walls, and for gardening purposes it is flat on top.  It can take whatever shape you like, from a large free form garden island to a narrow border.  When choosing a location in your yard for this method, take into account whether or not the berm will re-direct rainwater on your property.  For instance, you don’t want to channel water towards your foundation.  If you have a low-lying area that collects moisture, that might be a good place.

 You will need lots of newspaper (no plastic or glossy inserts) and then compost, manure, soil and double shredded mulch.  You can build the berm in the fall and let it “rest” over the winter, or whenever you like and plant into it immediately.  First cover the area of your berm with 5 to 7 layers of newspaper; this can be directly on soil, over grass, or over weeds that have been weed-wacked to ground level.  Wet this newspaper layer thoroughly.  Then (depending on the materials you are using) add layers of compost, chopped leaves, manure, humus and topsoil and top off with your shredded mulch.  The height of the berm is generally 18” to 24”, depending on what you are planting in it.  The plants will eventually extend their roots down through the decomposing newspaper and grass into the soil.  The berm will shrink as the organic material breaks down, and fresh compost and mulch can be applied each year.  Raised beds will accomplish the same thing, but you are tied to straight lines as opposed to the free form shapes allowed by berms.

Amending your soil or building berms or raised beds will eliminate the need for deep tilling, which destroys soil structure and all the small creatures that make it a living organism.  So don’t be afraid of your clay soil, make it work for you.