We learn these simple things because someone, somewhere along the way took the time to show us. Before we were shown, we probably did it wrong.
With that said, I should tell you all that I still can't play a DVD on my television without my wife's help; even though she's shown me at least ten times.
Sometimes we never get shown how to do certain simple things. We plod along, doing these things incorrectly, ignorant of our own incompetence. It wasn't long ago that I assumed hot water was always best for washing clothes. I still assume a flush beats a full house in poker.
In our gardening pursuits how many of us have ever been shown how to dig a planting hole - one of the most fundamental skills. I suspect most gardeners just picked up a shovel one day and started digging and pretty much do it the same way today that they did twenty or thirty years ago. They've never been shown.
Size of the Hole
One of the most common misconceptions is that a planting hole should be about as deep as it is wide. Furthermore, it the soil is heavy clay, most gardeners dig the hole even deeper. In fact, almost all planting holes should be much wider than they are deep, especially those in clay soils. For better drainage and root growth, a planting hole should be dug about three or four times as wide as the container and just slightly deeper. A shallow, wide hole is best.
Shape of the Hole
The hole should be round, right? Of course shovels have rounded backs which make the "round-hole" assumption almost automatic. But in fact, planting holes should be irregular in their outline, with jagged edges, creases and pointed corners. Round, smooth-sided planting holes might be easier to dig, but they discourage the roots from exiting the planting hole and penetrating the native soil around it. Rather than circling round and round, as roots are encouraged to do in a round planting hole; a hole with jagged, irregular edges will encourage the roots to break the confines of the hole and set off into the native soil.
The final instruction in my hole-digging lesson is to water the hole first, before planting. Most people dig the hole, install the plant, add the soil mixture back into the hole and then go get the hose. But, it is better to fill the hole with water now, while it is empty, and then proceed with the planting after the water has completely drained. This has two advantages. First, it lets you measure how good the drainage is in the area. If the water drains through the hole at less than an inch per hour, most plants are going to fail without more complex adjustments; but that's another article. Secondly, by soaking the hole first, when the planting is finished and the final irrigation is given, the drier surrounding soil will not wick the water away from the rootball, a common occurrence.
Any complete instruction of shrub or tree planting should also include soil amendments, placing the plant at the correct height in the hole, irrigation wells, checking the rootball for matted roots, plant handling and more. But first, the hole must be dug.
So there it is, after twenty of thirty years of planting trees and shrubs, you've finally been properly instructed on how to dig a hole. Good digging.
Ron Vanderhoff is the Nursery Manager at Roger’s Gardens in Corona del Mar.
Questions from Readers December 26th.
Unfortunately, I had to remove a large tree recently and I had the stump ground as well. The company left behind the stump and root shavings. Are these okay for planting?
No. the ground shavings from the stump grinding process are far too light and fluffy to support proper plant growth. They will also create a nitrogen deficiency as they slowly decompose in place over the next several years. Instead, these shavings should be removed from the area and can be added in moderation to a compost pile, along with some extra organic nitrogen fertilizer, until thoroughly decomposed. Otherwise, these shavings should be disposed of to a green-waste recycling location.