Horseradish is delicious. I just ran out of the jar from last year but luckily it is time to harvest again! Another round of snow is set to arrive Wednesday so I am busy in the gardens putting beds to sleep and harvesting the rest of the root crops. Horseradish is one of them.
If you could get a plant start from someone or from a nursery in the spring, horseradish will reward you with delicious roots for years to come as it spreads quite nicely. I only take about half or two thirds so that there is plenty to grow back. You may need a shovel to loosen a bit.
Horseradish is medicinal (as most plants are), and is excellent for sinuses and upper respiratory infections. You can tincture them in alcohol with Echinacea and garlic for a powerful antibiotic. Or you can take the culinary approach to medicine. A most delicious one, I must say.
Scrub the roots clean in fresh water. Cut into two inch pieces and place in a food processor. I like to add a small beet to mine for vibrant color but we had no spring crops and very, very few fall crops this year, so no beets. Grind on high for a bit until it gets nice and chunky. Add in a touch of vinegar for consistency and preserving. I used 2 Tablespoons for four roots. Continue processing until it looks nice and blended.
One might want to take the bowl outside before opening the lid. I never remember to do this. The fumes are mighty and a bit stingy. Beware. Scrape down sides, see if it needs any more pulsing. Pour into a small canning jar and keep in refrigerator. The vinegar will mellow the heat over time.
Add to mashed potatoes or cocktail sauce or whatever you like. What do you like to have horseradish with?
Farmgirl School 
You know, I’ve never thought about how horseradish is made. I think I may try growing it myself. Can you get the seeds?
I am sure you can!
What do I like it with? What kind of question is that? It is such an excellent condiment. I think it is most traditional with roast beef sandwiches. My neighbor makes horseradish sauce by mixing it with other ingredients so that it looks like coarse mayonnaise, but we do not preserve it like that. It gets a bit milder if canned. Because it lasts so long in the ground, I prefer to leave it there, and just pull up the oldest roots when needed, and then grind them as you describe above. Some of the oldest roots eventually bolt, and are no good afterward, but there are typically plenty more to replace them.
Yes, it would be nice to be able to harvest them all year if the ground didn’t freeze. The spicier the better! I bet a lot of fabulous sauces could be made with horseradish!
I do not know, but it seems to me that horseradish is not as popular in California as it is in other regions. Also, even though it is nice to be able to pull it any time of year (The soil does not freeze, and there is no snow.), I do not think that the flavor is as good as it is in more extreme climates.