Friday, December 29, 2006
Several (Not so Easy) Steps in Preparing Your Plant Beds After centuries of exploitation, our nation has only a few remaining areas of inherently fertile soils. With very few exceptions, our soils are low in organic matter, low in microbiological activity, and low in the three major nutrients: nitrogen, phosphate, and potash. They are also low in some of the secondary nutrients such as calcium and magnesium, and low in many of the micronutrients. They haven't always been this way, but careless farming, timbering, and pasturing for 250 to 300 years have degraded them considerably. The steps you take to transform your 'dirt' into productive garden soil depend on the type of soil you have and the depth of your pockets. Technicians might quibble over this simplification, but most soils are either sticky clay, gritty sand, or a mixture of the two with some silt--a mixture known as "loam." Modern Way to Prepare Flower and Shrub Bed Soil The old way was to till the soil, remove any grasses, remove sticks and rocks by hand, add lime and fertilizer, bring in and incorporate more soil to build up beds for drainage, and set out flower or shrub plants. Of course the weed seeds exposed by turning the soil and bringing in soil would begin germinating, and a regular routine of hoeing or pulling weeds had to begin. This approach differed little from practices in frontier days when soil was turned with a mattock and fenced with wattle to keep out wild animals. Today there is a more lasting way to prepare soil to increase aeration, improve drainage, decrease weeding, and conserve moisture. After reading the following procedure, you might think, "No way!" but if you improve one flowerbed at a time, you will soon have the nearest thing to a low-maintenance landscape. Devote a summer to getting rid of weeds. Either turn the soil repeatedly to kill emerging weeds or do it the easy way with 3 sprays of a non-selective, post-emergence herbicide, timed to kill new weeds as they emerge. Rake or burn off the dead vegetation. If your soil is clay and slow to drain, add soil amendments after the first tilling or application of herbicide. Haul in an organic soil conditioner such as finely pulverized pine bark to make a layer 3 in. deep over the weed-free bed. Also haul in cracked pea gravel, granite meal, Perma Till(tm) or chicken grit to make another layer 3 in. deep over the bed. Spread dolomitic limestone that is pelletized or ground very fine for quick release. Five pounds limestone per 100 sq. ft. should be enough for starters. Spread 3 pounds triple super phosphate per 100 sq. ft., or 6 pounds of rock phosphate over the same area. Forget bone meal--it takes forever to release. Spread 5 pounds organic fertilizer such as chicken manure per 100 sq. ft. Pelletized chicken manure supplies not only major and secondary nutrients, but micronutrients as well. If your soil is sandy, follow all the steps above, but omit the addition of cracked pea gravel. Mix in the additives to spade depth, about 9 in. The organic soil conditioner and cracked pea gravel will raise the level of the soil in the bed of clay soil and will improve drainage. The organic soil conditioner will improve the moisture-holding capacity and microbiological activity of sandy soil. Haul in and spread pine bark or hardwood bark mulch to a depth of 3 to 5 in. over the raised bed. (Ask for pine or hardwood bark mulch, neither a finely shredded soil conditioner nor coarse nuggets.) Now you are ready to plant. The deep layer of mulch will absorb and retain water and discourage weed seeds from germinating. Shrubs can be planted by raking the mulch aside, spreading out the root system, setting the root ball on top of the soil, and shoveling the mulch back over the roots. You might need to get a few more shovels full of mulch from the pile to make sure the root ball is covered. Annuals can be set into shallow holes dug in the mulch. Perennial seedlings will need bottomless tin can collars to keep the mulch from drifting over their crowns, a potential cause of rotting. Deeply mulched beds do not make good seedbeds for direct-seeding annual flowers. Start them in un-mulched beds and transplant the seedlings into the mulched area. Maintaining Soil Fertility and Depth of MulchOur long summers, high rainfall, and high temperatures conspire to volatilize, or leach nutrients out of the soil, and to turn mulch into compost at a rapid rate. Work in one-half cup of organic fertilizer around every annual plant that is set out. To feed our established perennials, rake the mulch from around the collar, scatter fertilizer at the rate recommended on the package, and pull the mulch back over it. Shrubs are larger plants and can utilize greater amounts of fertilizer. Follow the directions on the package for rates.