by Charlene
Barr
Colorado State University Cooperative Extension
Master Gardener
Larimer County
Q. I am ready to roll up my sleeves and begin digging. What is my first garden chore as I prepare to plant?
A. Adding a soil amendment before planting is like money in the bank. One must put in before one takes out. Soils in Colorado generally are either sand or clay--nothing in between! In either case they are almost totally lacking in organic material. The recommendation is to have your soil tested so that you can amend based upon your particular soil's needs. If you do not have time to do the soil testing at a lab, do this simple soil test: Roll some slightly moistened soil between your thumb and forefinger. If it forms a ball, feels smooth and becomes sticky, it is high in clay and you should add organic matter. If you cannot form a ball, the soil will not stay together and it feels a bit grainy and coarse, it may be too sandy to hold enough water, and organic matter should be added. In sandy soils, organic amendments act as sponge to help retain moisture. In heavy clay soils, they help to loosen the soil and create air pockets-–a necessity for healthy roots. Therefore, organic compost and sphagnum peat should be added by either layering it on top of the soil and tilling it in, or by working it in plant by plant.
Q. What is sphagnum peat and how important is it to soils?
A. Sphagnum peat is harvested from bogs in Canada and the northern United States. It is generally acidic and can help Colorado gardeners grow plants that require a more acidic soil. A few plants requiring acidic soil include spinach (Basellia alba), horseradish (Armoracia rusticana), Saskatoon serviceberry (Amelanchier alnifolia), columbines (Aquilegia, ssp.) bugleweed (Ajuga reptans), foxglove (Digitalis grandiflora), globethistle (Echninops, ssp.). Colorado mountain peat is not a good soil amendment because it is too fine in texture and has a higher pH. Mountain peat comes from high-altitude wetlands, and it may take hundreds of years to rejuvenate.
Q. My neighbor uses supermarket manure in his flower garden, but not in his vegetable garden. Is manure better to use than compost?
A. Fresh manure is extremely high in elevated ammonia levels (too much salt for Colorado soils). Aging manure at least four months will kill potential pathogens (i.e. e. coli) before use in vegetable gardens. Manure is best used in flower gardens, shrub borders and other non-food gardens. Composting manure at temperatures of 130 to 140 degrees F kills pathogens and alleviates ammonia gas from manure, thus reducing nitrogen levels and increasing the phosphorus and potassium concentrations. Composted manure increases salt levels in garden soils. Think twice before composting with manure.
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