Anyone know when horseradish should be harvested? Hey Sue, Can only tell you what I've read & done and my horseradish is HOT. Plant in early spring in well composted soil with lots of hardwood fireplace ash. Water well all summer & try to keep the slugs from ruining your plants. After first few frosts, but before soil freezes dig up 1 root with pitch fork (This should be an "R" month, Sept./Oct./Nov./Dec.). Scrub root with veggie brush & peel all brownish exterior so you only have white roots. Cut main root into chunks & put in food processor with 1/4 cup white vinegar saving smaller shoots for chawin' on while doin' all this chopin'. Blend until finely chopped and check consistency, you want it just like store bought horseradish. If it's to watery throw in some of the smaller shoots, if to dry put in a tad more vinegar. Let steep a week or so then taste. Hot? Leave rest in ground until soil defrosts in early spring and repeat process. You'll never harvest horseradish in a month that ends in R again IMHO the freezing process puts the heat in horseradish, Paul (the NorthEast ChileMan) PS OOPS!! Didn't think to ask if your ground freezes!!!