Q. Mike: I have three horseradish plants growing in raised beds, each in their second year. Can I leave them in longer and still have them be edible? Should I re-plant a portion of the root next spring, assuming I should harvest this fall? Can it be powdered like you advise with garlic (dried and then ground up in a dedicated 'coffee' grinder)? Basically how does one go about tending horseradish? Thanks.
- ---Tony from Fairfax VA
A. Horseradish is a pretty tough root, Tony. The only thing this mustard family member requires to become a big, long-lived perennial is deep, fertile soil—so your raised beds are the perfect home for this pungent spice. But three plants is a lot—and horseradish has a reputation for getting out of control, so unless you're thinking about going into the horseradish business, I'd cull it to one bed this Fall.
Some people grow it as a perennial and some as an annual. The perennial people wait until frost has killed the above ground growth, wait through a couple more frosts (this improves the flavor), dig up the entire root, save the biggest sections for kitchen use and immediately replant a few of the smallest sections. Don't reverse that order--big pieces left in the ground can get woody after a year or two. (So can horseradish that gets dehydrated, so make sure to water during dry times to get the best eating quality at harvest time no matter which method you choose.)
The annual crowd harvests everything in the Fall—again, after a few frosts have intensified the flavor. They use what they need, and then store a few small pieces in the fridge or in damp sand in the cellar for replanting in the Spring.
In your region—just outside of Washington, DC—you could also leave the root in the ground over winter (heavily mulched) and dig up portions as needed; it's the easiest way to keep it fresh, and the flavor will continue to improve as the ground gets colder. Then watch for the very first sprouts to appear above ground in the Spring and immediately harvest all but what you intend to replant; once that new growth takes off, the root gets 'watery' and loses a lot of its flavor until cool weather returns.
Processing? It's not for the timid! Heat is said to quickly dissipate the flavor, so I personally wouldn't dry and grind it. You're welcome to try a small batch, but I would not attempt such a thing inside the house—unless you happen to have an infestation of bedbugs, termites or some other unwelcome guests you'd like driven away. (Horseradish tea has a long reputation as an effective outdoor pest control.)
The typical way to process horseradish is by grating. Wash the roots you intend to use, peel them, and then grate them by hand or use a food processor. Warning: this very pungent mustard root gives off fumes that are killer. Do any grating outdoors with a strong fan blowing the fumes away from your face. Hand grating indoors is NOT recommended! I'd even open a food processor that held grated roots outside with that fan going strong behind me.
Use some of the grated root immediately; it will never taste better. If you have leftovers, bottle them up in some vinegar and keep it in the coldest part of your fridge. The unpeeled root itself will also store well in a cold fridge, allowing you to make up what you need pretty much anytime over winter.
Q. My horseradish comes back every year but the roots are pencil size. Is there a method to get the big fat roots that we see in the grocery store? I'd like to use it for my Passover Seder.
- ---Sonja in Bethlehem, PA
For Passover—a Springtime event—I'd plant roots in a plot of loose rich soil the Spring before, keep it well watered over the summer, let the top growth die back naturally, mark the position, mulch the surface well, let it sit down there all winter and then harvest just before Passover—or a little earlier if it starts to regrow. Once you get the timing down, you should be a reliable perennial provider of the traditional "bitter herb" for the Seder table.
Q. How do you get rid of horseradish? Over the years it has crept into every part of the yard. Despite weed killers like Round Up, it always returns.
- ---Grace (no location)
Let this be a warning to all: Handle it diligently and horseradish will become a dependable perennial. Ignore it for years—or God forbid, till the soil it's growing in—and it will become as evil as running bamboo.
Instead of spraying, you need to dig. As soon as the distinctive sprouts appear in the Spring, get the entire root out of the ground. If it's been unchecked for years, take a few seasons to eradicate it by removing it from sections of your yard at a time.