Amending Clay Soil



Oh the North Carolina red mud. It sticks to your shoes, stains your clothes and makes a mess. Plus, it makes gardening a little difficult.  It’s rock hard when dry and when it’s wet, a gloppy mess. But for most of us in this state it’s what we have to work with so we must find a symbiosis.  Red clay is actually full of great nutrients however, it lacks the microbes need to break it down.  What are we gardeners and homeowners to do?

It is best to amend your existing clay soil.  For annual and vegetable beds where you are digging in the soil several times a year, amend with organic matter. Aged, grass clippings, ground leaf mulch, compost, pine bark fines and aged manure are all excellent choices. They should be mixed into the soil six to twelve inches deep.  The best method is using a tiller – if you don’t have one it’s an investment serious gardeners should consider, or you can rent one here at Atlantic Avenue at reasonable rates.  Never amend clay soil with sand or peat. Sand and clay is the basic recipe for making bricks. Peat holds water the same as clay. This makes for too much water for any of your plants.

For the more permanent parts of your landscaping turning organic matter into the soil is not so easy. You can amend the soil one hole at a time when you are planting a tree or shrub, but as those plants grow and the amendments decay, you can’t add more without causing damage to the roots. In these areas it is best to add organics on top of the soil and let the bugs, worms and fungi do the work of turning it into the soil for you. You can hide these additions under a layer of mulch, which will also help to feed your soil.

Digging in clay is hard work. If possible, plan your day to dig; two to three days after a rainfall clay can be broken up into smaller clumps which make it easier to mix with amendments. Learn to use a pick ax safely. A hole dug using only a shovel has smooth solid sides that are hard for roots to break through- make sure to rough up the edges as well. When planting, make sure not to sink your plant all the way into the ground. You will be sinking it into a bowl of water whenever it rains. The best planting method is to keep it sticking up above the edge of the hole. You can mound up soil and mulch around it. Do not fill the remainder of the hole with only new ‘good’ dirt. Your new roots will grow great until they hit the wall of clay, at which point they will begin to circle, maybe for years, helplessly unable to break through. Mix at least half of the broken up clay back in with planting mix before you fill your hole.  For additional help with planting see our Successful Planting Guide.

Don’t be intimidated by gardening because of a little bit of red mud. Embrace and work with the soil, taking care not to get too muddy while you do.

See this page for a list of our favorite soils and amendments.