Get that special gardener in your life a soil test for Christmas
By Bonnie Orr
WSU Chelan/Douglas County Master Gardener
A perfect gift for a gardening friend is a soil test. Commercial soil tests indicate various levels of basic nutrients in the soil. Mostly, they calibrate the fertility of the soil to guide the gardener’s use of fertilizers.
The tests, among other features, indicate the level of nitrogen, phosphorus and potassium. Some tests also indicate pH and micro-nutrients such as calcium or magnesium or boron. Gardeners often find that their soil actually has enough of the major nutrients and more bags of fertilizer do not have to be purchased.
Soil tests are particularly valuable to gardeners who use animal manures to fertilize their garden because the percentage of NPK (nitrogen, phosphorous and potassium) are not predetermined as they are on a purchased bag of fertilizer.
Some gardeners mistakenly consider that compost has higher levels of nutrients than it actually has. Completed compost contains very low levels of NPK (perhaps 3-2-3) but often includes micro-nutrients.
Even more valuable than a NPK soil test is the determination of the soil types.
Soil is made up of small particles of essentially ground up rock. The rock type and the particle size determine the soil type: sand, clay, loam or silt.
An awareness of the garden’s soil type guides the gardener’s application of irrigation water.
For example, sandy soils do not hold water for long periods of time as the water tends to run straight through the soil. Clay soils hold water that pools out laterally, and silt and loam soils have characteristics of both sand and clay. Healthy soil has about 10% organic material. The organic material holds water more effectively in sandy soils and enables water to move through clay soils rather than puddling. Organic material is added with compost or cover crops.
It is interesting to find out what type of soil is in the garden. You can do a soil analysis for your gardener friend by a couple of different methods.
The quart jar method is easy and quick. This website tells how to determine your soil type: wwrld.us/quartjar.
Your hands can also help you find out your soil type. Pick up a handful of moist soil. Is it gritty, with lots of sand? Does it stain your hands with lots of clay? Does it stick together into a ball, another indication of clay? A comprehensive tutorial on soil types from WSU is found at wwrld.us/diysoiltests.
Have fun creating a unique Christmas gift for your friend.
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