Monday, May 1, 2017
Clay, Clay Go Away
This photo from the internet is captioned "Red Clay Cliffs of Guam". I grew up on Guam and the red clay was everywhere. It was soft, slick and squishy under my bare feet after our tropical rainstorms.
Clay is the tiniest soil particle. It is almost invisible to the naked eye. I'm not sure you can even isolate a single clay particle without the use of a microscope. Consequently, lots of clay particles can pack really closely together and form a horizontal matrix that allows them to have great surface area. This characteristic is what makes clay stick to well to itself. (Think giant hard clods of the stuff) However, clay does have a positive side, it is relatively fertile because its particles are negatively charged and thus, attract nutrients like magnesium, calcium, and potassium.
As a master gardener, I have always repeated the mantra "the cure for clay is compost" this still holds true but there are many more things you can do to loosen up that hardpan clay.
1. Do not further compact your clay soil, do not work it when it is wet and so not step on it after you have worked it.
2. Add good compost or well-rotted manure to your soil and dig it in 4-6 inches.
3. Mulch your soil to prevent it from drying out and forming rock hard clods. Use leaves, straw or even cardboard.
4. Break up hard pan soil by planting daikon, parsnips and other deep-rooted crops.
5. Plant cover crops like fava beans or alfalfa, they have deep roots that will help break up clay then, you can till them into the ground in the spring before they go to seed, for "green manure."
Amending and remediating clay soil is a multi-year process, tt takes time for the organic matter to do its work. As with almost everything in the garden, be patient, you reap what you sow.