Answer: I have not heard about any particular need horseradish has for calcium. The most important thing is a deep, moist soil rich in organic matter. Since you have a naturally high soil pH, I would not add lime.
Because horseradish is a perennial and can be invasive, some gardeners plant it in boxes to confine it. Another way is to sink a 5-gallon pail (with large drainage holes, or with the bottom removed) right into the garden. If you choose one of these methods, you can mix your own soil to fill the pail. If possible, I would use at least half compost in the mix--this will help modify your high pH. Do not use manure unless it is very well composted. Too much nitrogen will result in tough roots.
Although horseradish is a perennial plant, many gardeners treat it as an annual and plant it fresh each year. In theory, a bed will continue producing indefinitely. However, older plants usually yield progressively smaller and tougher roots each year.
Here's an interesting web site about horseradish:
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