Where does one get a reliable soil test? How long does it take? How much does it cost?
I tried looking online but came up with nothing but broken links.
There are various private soil labs that do testing - the cooperative extension service no longer offers this service. The attached link is a database from WSU of various soil/water testing labs.
Prices and procedures will vary, as will the types of testing offered.
Here is a link that might be useful: WSU soil lab database
Although a comprehensive soil test can be useful, but in most cases all you need to know is the pH. This is the measure of soil acidity or alkalinity. Acidic being sour, alkaline being sweet. Most garden veggies thrive at pH range of 5.9 to 7.2 (7 bing nutral. and higher is sweet).
To test pH, you can get a simple device (ferry morse, from HD) or get a test kit and test your garden soil's pH ,by following the instruction. This might not be as accurate as a lab test BUT it can give a prety good idea as where you stand. A (+) or (-)0.2 or even slightly more, is not going to be that critical. Because, it has been established that most plants can thrive within a RANGE of pH , not an EXACT level of it. Although some prefer slightly acid and some like slightly alkaline soil.
In Western Washington, generaly, all soils are acidic because the source of native soil is not calcium. Calcium make the soil sweet. plus, the continued rain leach positive ions , making the soil more acidic. That is why they apply gypsum, lime..that contain calcium to reduce acidity.
The thing with regular lime sold for this purpos, is tha it taks months before it actuall can reduce acidity(raise pH). Fast acting limes are somehow better but cost more.
Super Sweet Lime says it's fast acting so that's the way to go?
The vast majority of plants prefer slightly to moderately acidic soils - like we have throughout the NW on the western side of the Cascades. In most cases, supported by the WA extension service, liming your soils is not necessary. In fact, increasing or bumping up the acidity is sometimes desireable.
A baseline soil test is always a good practice, just to let you know what you are starting out with before any amending happens. And this is especially true for vegetables or annual crops that have rather significant nutrient demands as well as pull a lot of nutrients from the soil.
FWIW, gypsum has no measurable effect on soil pH.
Here is a link that might be useful: the myth of gypsum