When creating a garden setting, the idea is to create something beautiful and artistic that will last. This includes the use of many different types of plants, grasses, shrubberies, and trees. Beds, Borders, and Planters need to contain the proper amount and type of soil depending on the needs of the plants. The soil must contain enough food for the plants, is the proper depth, and should be pure.
Often times the soil we have available is not necessarily the type of soil we desire. This means that artificial means have to be taken to make the soil suitable for your plant life.
Lets use an example of a garden plot being laid out on virgin soil, where the plot has been staked out, on old pasture ground. The soil may consist of a top of brown loam over a clay subsoil. The overlying soil may not be proper for your garden beds and borders, and the gardener may need to take other means.
If the subsoil is not of a terrible consistency, the proper procedure is to create an admixture of soil and subsoil to temper the clay soil. This should be done about two feet deep, which is the basic requirement of horticulture.
To create this mixture, the technique of trenching is best. Trenching referes to spade work that creates deep tilling. This is not the same as digging, where you simply turn over the soil. Trenching should be done in the late fall, before the weather turns too cold.
Full Trenching refers to literally reversing the positions of the upper and lowers layers of soil. This allows whatever was two feet below to come to the top, and the loam rich soil to go to the bottom.
Grounds that have long been in tillage benefit from full reversals. These grounds are already broken to the trenching depth. This would not be advisable for new ground that has not been broken for a long time. This ground has not seen light in a long time, and would be bereft of the proper nutrients needs for plant care. Full Trenching then, results in poor top soil for the gardener.
The idea of “half-trenching” is a much better plan. This involves removing the surface in specific sections, breaking the subsoil up, and replacing the surface soil. This method works, but a better method would be to mix the soil and subsoil to the proper depth. Begin by cutting a trench across the border the full desired depth.
The soil should be removed to the far end of the border. The gardener should then fill in Trench A with soil from other trenches, repeating this with all trenches, until the spaces are full. In the case of the pasture, be sure to bury and turfs so that that may contribute to the enriching the soil.
The goal of trenching is to create suitable soil, it also creates an opportunity to enrich the soil by adding manure into the mixing process. This opportunity is important to take, especially with the creation of new gardens and borders.
Manure should be added to the soil as the trenching occurs at a regular rate, treating the whole contents of the setting. This needs to be done so that the manure reaches the proper depth as well, and not just at the surface level. This manure will allow the plants to find food as they send down their roots.