|What soil amendments are best for growing horseradish? The garden catalogue I ordered my horseradish crowns from states horseradish grows best in well-limed soil. This seem to imply either a need for a lot of calcium and/or a high soil pH. Most of the references recommending the addition of calcium refer to preventing blossom end rot, breaking up heavy clay soil, or treatment for high sodium content, but nothing about any root crops and in particular horseradish. Instead the search I did at this internet site seems to indicate manure, compost, and peat are the preferred choices for preparing horseradish beds. These amendments, as I understand from this internet site and other literature, typically lower the soil pH and improve soil texture. I found nothing indicating they have any significiant effect on calcium content. We have a naturally high soil pH in our area, often as high as 8.5, and in most cases we have to lower the pH to get good results. Could I add gypsum rather than lime if a calcium requirement is the reason?
|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: