Oh sure, fried green tomatoes are ok; but I'll take an extra helping of friable soil any day! This is the desire of any gardener who attempts to sink a shovel into the clay found in our area. Clay just does not make a great sandwich. Takes a lot of mustard...
Ok, ok? put the wok and the peanut oil away; and don't forget to turn off the stove. I wonder how many times I've used the term "friable soil" in our garden center and not been understood? Their heads nod up and down but the eyebrows narrow in puzzlement and I have to wonder what horrible things are served at dinner later that day.
Friable means easily crumbled. Loose, open, un-compacted, well drained, friable soil gives the best results in most gardening situations. There are of course plants that will thrive in clay soil; otherwise Midwestern Ohio would be a barren desert! However the vast majority of desired ornamentals and food crops will perform better in a deep bed of improved soil.
Plants need to move and breathe!
A typical complaint I hear from the weekend home improvement landscaper "Our soil is so hard to dig in!" Well if it's tough for you, it's also tough for the plants roots to move in. And the more developed a plants roots are, the better it can grow and handle stress, drought etc. Also most of us know plants need water, but may forget that the roots also need oxygen. Dense, wet, soils have little "airspace" between the soil particles. Friable soil's loose structure allows the water to drain through and lets the air in; making the plants grown there more tolerant of heavy rains or (gasp!) over-watering.
Add Organic Matter!
Spock: The organic matter content must be increased by a warp factor of 3.7 to aerate and provide structure for the Zabar nebula zenopods.
Captain: Scotty what's going on down there!
Scotty: The organic matter generators dilithium crystals are all but shot Cap'n. She's givin' ya all she's got!
The answer is much simpler here on earth. If you have a compost pile you already know about using organic matter in your garden. Double-dig, till, whatever it takes to get that stuff worked into your soil till have beautiful crumbly soil. Garden centers will also stock many kinds of soil amendments such as composted manure and peat moss. In our area, peat moss gives the most friability bang for your buck, but it's worth asking what the best option is at your local garden center. Sometimes a local bulk compost source is available. If you have a large amount of soil to improve this is worth checking in to. If you are on a budget, do the cutting somewhere else! Always start with the soil! Adding organic matter to sandy soils also helps with soil structure. If the soil is too loose then it may dry out or not provide enough mechanical support for the plant. So you rarely go wrong adding organic matter.
One caveat
If you have very heavy clay soil, when planting a tree out in the yard, drainage can be a real issue. This is a situation where improving the drainage of the soil in the planting hole can really work against you. Imagine this basin dug into the clay filled with nice fluffy soil. It begins to rain. A man is singing and dancing in the street splashing in the gutters. The rain hits the hard soil around the basin; some is absorbed, some is runoff into the softer soil of the basin. All the rain that hits the soft soil of the basin flows right through it until? It hits the hard clay bottom of that basin and begins to fill it. Essentially we've created this sunken clay bathtub for our tree's to drown in! Also if the soil is significantly improved in the planting hole the trees roots will tend to circle, hitting the hard clay and turning; "choosing" to stay in the looser soil. This can lead to a choking effect and a smaller root system.
There are other things to consider about your soil besides it friability. PH, nutrient deficiencies, microbial content, and contaminants are things that may be sampled, analyzed and treated; but nearly all my projects simply begin with a bale of peat moss and a shovel.
A garden center manager, writer, musician and webmaster; Lee Goins is often called on as an expert in landscaping and gardening. Residents of Shelby County Ohio have been bringing him pieces of trees, moldy leaves, and jars of bugs for 8 years in spite of the well publicized knowledge he prefers chocolate. His gardening help has been featured on TV, Radio, Newspapers and websites like http://www.shelbylandscaping.com