Many garden-farmers are adding soil amendments in March & April, before planting..
I'll list some soil labs below that do testing.
At times it can be worth your time - energy to obtain a soil test.
You can obtain a rough idea of how balanced/unbalanced your soil is in its acidity, macronutrients (N-P-K) and also in its trace elements. The more deeply nourishing & balanced our soils are, the more nourishing our edibles are.
Biodynamic preparations used in soil nourishment, can grow foods that result in the most satisfying & nourishing meals.
However those preparations require a lot of work, knowledge, timing, and access to healthy cows manure & special horn.
If you are fortunate you find & help a biodynamic farmer friend in making the preparations.
As garden-farmers, when we are diligent in recycling All our nutrients, making compost & covercrops, then a soil test can be more a matter of curiosity.
For a CSA share using biodynmic principles consider this from Farmer Brian at Inspiration Farm: http://transitionwhatcom.ning.com/forum/topics/biodynamic-csa-share...
For many of us, a soil test make good sense, at least occasionally. Steve Solomon writes about finding the weakest link in our soils that are used to grow our edible nourishment. (“The Intelligent Gardener')..Sometime this may mean adding a trace element, other times it may mean not adding a macronutrient, such as Potassium, that may be too high in our native Cascadia soils. Consider at least reading pg 84- 192 in his book. (Also consider Farmer Walters perspective in his book 'Physics Are On My Side” pg 133-157 or consider a working visit to his farm http://www.fafarm.org/About_Us.html )
Many garden farmers don't have the extra time & resources to do a soil test every year, but it does make sense to do it the first year you grow on the land, and to consider in the future if you are questioning whether there may be in imbalance or deficiency. Also consider a test after any major disaster or climatic event...ie flooding or toxic spills, volcanic eruptions....
Remember, our wild plants and 'weeds' bring up lots of trace elements from the subsoil. These are an important source to our compost piles & foliar sprays. I know no longer weed. I harvest plants & manure for my compost.
Here are the two labs that Steve Solomon recommends:
Spectrum Analytic http://www.spectrumanalytic.com/services/analysis/agsoil.html
A&L Western Lab in Portland was recommended to me from Farmer Billy of Moondance: http://www.al-labs-west.com/sections/anservices/soil/fees “They have a pretty quick turn around and will give organic recommendations if requested. They also offer graphical analysis and will email you the results. There are different fees depending on how detailed of an analysis you want but I order the S3C complete usually. Call them and they will walk you through it.”.
I don't know if the Ag Extension still offers soil test, like they did in the past.
I don't know anyone locally yet, who has initiated a small business, that would travel to a garden-farm, do the soil test, analyze the results, and then provide & apply the soil amendments to move towards greater balance.....and return to also provide foliar sprays on crops.
Olympia amendments business that carries some of the trace elements: http://www.blacklakeorganic.com/OresRockMinerals
I'm interested in meeting with others at our edible garden-farm-pollinator sanctuary that want to study soil balance & nourishment together....Especially during a less busy season of our growing year.
Please share your thoughts on any soil labs you've used, and any major soil imbalances you've found in your own soil, plus affordable sources of soil ammendments, many of which are mined and use fossil fuel for shipping.