You can prepare garden soil in fall or spring depending on the amount of clay. Convenience to the gardener may also be a factor. Most gardeners don’t get around to preparing garden soil until it’s time to plant their seeds. However, fall garden soil preparation has many things in its favor, which you might keep in mind when October rolls around again.
While sandy soils should be chosen for the garden because of their ease of handling and excellent drainage, a few unfortunate gardeners are blessed with clay. Fall plowing of clays allows frost action to breakdown clods and form fine granules that allow easier gardening. Gardens not fall plowed or spaded will need such preparation in spring. Spading works best on small areas of less than 500 square feet, but anything larger gets to be work unless you happen to be a bug on exercise.
Plowing is the time-honored method of breaking up soil used by farmers. When properly done, it fractures the soil mass into granules as it passes over the moldboard. Surface debris is buried in the process so that decomposition may proceed. The main trouble is that today’s gardens tend to be small for such a large tool and many urban gardeners can’t find an operator with the equipment to plow.
Rotary tillage tools of several types have come into their own. They slice, chop and chew their way through the garden, producing an action not unlike an eggbeater. However, they should not actually whip the soil, as the granular structure may be reduced to fine powder. A coffee ground consistency seems best. Above all, don’t rototill soil when it is too wet. Rototillling has the fault of leaving soil too loose and fluffy, but ease of using garden sized machines, both for tilling and cultivating, makes them popular. Just make sure the soil in your garden has a chance to settle for a week or that you take the trouble to pack it back down again.
Seeds placed in too loose soil will not remain moist. Water cannot move up through disrupted capillary pore spaces from down below. Farmers use corrugated rollers or press wheels to firm soil around the seeds they plant. Use a roller in your garden or walk down newly seeded rows heel-to-toe. Tamping with rake or hoe is often practiced in small gardens.
If you prepare garden soil in spring you will have the the opportunity to improve the organic reservoir in your garden. Before any soil preparation, add manure, compost or other source of organic matter. An inch of such material is not too much and every little bit helps. Remember that continuous gardening literally “burns out” organic matter. Actually, the organic matter is decomposed more rapidly by soil bacteria due to the increased oxygen in soil air.
Wet soils and compacted soils allow organic matter to last longer. On the other hand, your garden grows better from having decomposition speeded up. Plan to add ground limestone at 25-50 pounds per 1000 square feet before preparing the seedbed. You may also add about half of the year’s application of complete fertilizer.
Lime, fertilizer and organic matter should be all mixed into the soil at seedbed preparation so newly developing plants are able to benefit from the day they start to grow.