We have known people who spend hundreds on plants and pennies on soil amendment. While good for the garden center, it is a poor decision on the part of the consumer. Although buying compost is certainly not nearly the fun that may be had with blooming daylilies, that investment will help assure you that the daylily (priced at $14.99!) will thrive and return to your garden bigger, stronger and more floriferous every season for many to come. The following was prepared by our landscape designer. This is how the pros do it.
In general, we prefer to see a depth of 12 to 16” of friable soil for the ultimate in plant and gardener success. This however can be quite impractical under most situations, so a little adjustment now and then needs to be considered to get the gardening experience moving with positive momentum.
One of the most important steps to take before planting your garden is to assess the quality of your soil. Often, day lectures are presented by garden centers and cooperative extension staff on the topic of soils. Do not make the mistake of guessing about your soil unless you have a fairly easy,obviously good soil (old established vegetable garden which enjoyed great productive years, foundation gardens which are growing like crazy or other telltale signs that the soil is pretty darn good). Get a soil test. This test will be your initial data gathering stage from which all future moves will be made. You mght consider this the rules with which you will be working. Get a pH test, a nutrient analysis and an organic matter content result. These 3 pieces of information compiled by the soil testing laboratory at the University of Maine in Orono will then be given you with recommendations.
You also need to know about the structure of the soil, such as clay or a sandy loam. The structure will dictate your plant choices or will dictate the correction process which will then allow for the plants you wish to grow. Understanding the structure can best be determined from a landscaper, a cooperative extension agent or by sending a sample to the soil testing laboratory.
When the soil is understood, then the steps of amending/correction are made. The correction steps may be as simple as adding organic soil amendments over time, to digging down 16” and placing a drainage tile and refilling with garden soil.
All the above being said, here is an alternative method which can work pretty well in most circumstances. In the planned garden spot, remove 6-8 inches of soil if there is any question at all about the health and usefulness of the soil. Then till or turn over the next 3-4 inches of soil. Add new loam to the bed, but only add 3-4 inches. Thoroughly mix the bottom 3-4 inches with the new soil layer. This helps to get a decent soil layer down to a depth of 11-12 inches and provides for a smooth transition throughout the first 12 inches of soil. Add to this mix superphosphate and lime. Add the remainder of the soil, mixing in fertilizer, lime and some superphosphate and leave it slightly raised by 2 inches or so. Over time the soil will settle. Ideally, a somewhat raised bed, after settling, is preferred over level or worse, a saucer shaped bed. By leaving the bed somewhat raised, you gain an additional 1-3 inches of soil depth and improved drainage. By digging down only 8 inches, you have created a soil depth of as much as 14-15 inches. You now have a garden soil which will serve you well in the years to come.
Finally, remember to add composted organic waste to the soil each year. Apply over the soil surface and scratch in to the first inch to 2 inches of soil. It will not be long before you see a remarkable difference in the quality of the soil.
Lime needn’t be added for about 3 years, at which time another soil test would be appropriate. This soil test will tell you alot about where you are headed with your current soil. If you have done everything recommended, you may not have to do another test for many years to come, if ever.