by Brian Minter
March 31, 2001
We spend a good deal of time, effort and money on seeds and plants for our gardens, but do we really give equal time to our soil preparation? Even the best seeds and plants are going to run into problems if your soil is not up to snuff.
There is a very simple test for good soil texture that anyone can do. Simply grab a handful of moist soil and squeeze it as hard as you can in your hand. Next, try crumbling it with your thumb. If it crumbles easily, you are in good shape. If it stays in a hard lump, you have some work to do. Gravelly soil can usually be enhanced with compost, manures and peat moss. Heavy clay soils, however, need more work. If your soil is fairly heavy and hard to work up, try using fine fir or hemlock sawdust or bark mulch to break it up. Depending upon the amount of clay, you may have to ali from four to six inches of sawdust or mulch to really open up the soil. Remember: this step is only meant to help break up the clay. You still have to ali organic matter to improve the texture and level of nutrients in the soil.
There seems to be some reluctance to use sawdust or bark in gardens, but let me assure you, it really works well. It is always wise to ask about the salt content of the bark and whether or not the sawdust has been treated with any chemicals during processing, but I have seldom heard of any problems. Try to avoid using cedar because it may contain some phytotoxins. The other concern I hear so often is the fear that bark or sawdust will rob the soil of nitrogen. This usually occurs during the breaking down process when bacteria consume nitrogen more rapidly. Depending on how much bark or sawdust is used, this can be true, but rain leaching our soils can also cause the same problems. Don't forget, by the way, that nitrogen can be quickly replaced with organic matter or high nitrogen fertilizers like 21-0-0. Along with the bark or sawdust, it is not a bad idea to ali some sand to provide a little weight for better distribution throughout the soil. When you finally get the texture you are looking for then it is time to begin building up your soil.
Rototil deeply a four to six inch layer of well rotted manures or compost to create a wonderful texture in your soil and to greatly enhance its ability to produce. A good organic based soil will not only provide initial nutrients, but will also hold onto those nutrients far longer into the season. Enriched soil will also keep beneficial bacteria working to further improve the soil.
When you make dramatic changes to your soil in this way, you are definitely going to affect the pH level of the soil. This simply means the acidity or alkalinity of the soil, measured on a scale of 1-14. Soils with levels measuring 1-7 are acidic; soils with levels 7-14 are alkaline. It is ideal to keep the pH balance somewhere in the neighbourhood of 5-8. Inexpensive pH meters or testers can be purchased to help identify your soil's pH level. Acid soils can be corrected with lime, while alkaline soils can be brought into balance with sulphate combinations. Plant growth can be adversely affected if the balance is too far out of line.
Now, after all of this is done, your garden is ready to go. Remember: raised or bermed beds are more productive and wide row planting uses space more efficiently. Fertilizers can be used to enhance a plant's growth or development. When a good deal of manure or compost is used, you will find phosphates and potash will be needed to slow down top growth and build root systems to keep the plants strong and productive.