Are you overloaded with new ideas for perennial beds and borders after visiting friends or public display gardens? Seen lots of unfamiliar and interesting new plants at the nursery? If so, fall is an excellent time to prepare fall garden beds for planting now or in the spring. The cooler temperatures, weaker sunlight and shorter days of fall mean less energy goes into top growth and more into establishing a strong root system. Planting in this area can usually continue through October.
After choosing the proper plants for your location-taking into account plant hardiness and the amount of available light-the most important thing you can do to insure success is to properly prepare your soil.
After marking off the area, you need to rid it of perennial weeds. Rototilling will only increase your weed crop, so you will need to carefully pull all underground stems and roots. Be sure to also remove any additional roots you find when you turn the soil over.
The soil you’re aiming to create should hold moisture, but also be well drained. If it doesn’t drain well now, it probably has high clay content. The actual soil particles are very small and pack together very closely, suffocating and drowning plant roots. Adding gypsum to clay soil can help break it up.
If your soil drains very quickly and you need to water frequently, it is probably sandy. Soil particles are relatively large and fit together loosely. Plants rarely drown in sandy soil unless the area is low-lying or the water line is high. In this instance it would be best to make a raised bed.
The solution, both for maintaining good drainage, and moisture retention, is generous amounts of organic matter. It separates clay particles, creating air space, and holds water and nutrients in sand. Good sources of organic matter are finished compost, well-decomposed manure, leaf mold and damp peat moss. These should be incorporated into the soil when it is turned over to a depth of 12″ or more. At this time you can also remove any sizable rocks, roots or other debris.
Most perennials grow best in a soil that is slightly acid to almost neutral-a pH of about 5.5-6.5. Most soils in this area are probably very acid and will need to have lime added every 2-3 years.
If you prefer to estimate your fertilizer needs, there are a few things to keep in mind. Phosphorous, and some of the trace elements, even when present in the soil in sufficient quantities, are only available to plants within a fairly narrow pH range. Keeping your soil pH at 5.5-6.5 should be adequate for most plants.
Fertilizers can either be natural, or you can use dry or granular fertilizers that are either quick or slow release. You can use either type if you are going to plant now. If you are going to delay planting until spring, wait and add the fertilizer then unless you are using natural fertilizers which break down slowly and will not leach out readily.
Natural fertilizers should be incorporated into the soil when you turn it over, especially phosphorous (bone meal, rock phosphate), as it doesn’t move readily through the soil. Dry or granular fertilizers can be sprinkled on the surface and raked into the top few inches of soil.