Horseradish is at its best in fall and winter. Like so many other root vegetables, however, it stores well and is often available in decent shape well into spring. Jerusalem artichokes/sunchokes are brown nubs, that look a bit like small pieces of fresh ginger.
Using Ms. or Mrs. in a cover letter depends on whether or not you know the marital status of the woman. If you are ever uncertain, it is always safe to use Ms. because it does not make an assumption about her marital status.
Be sure to address the cover letter's recipient specifically, even if you need to call the company and request the name of the person in charge of giving job interviews. Open the letter with a formal salutation. Dear Mr. Smith is acceptable. You can also use the person's first and last name.