Gently wrap the end of the spears in a damp cloth (wring it mostly dry first so it’s only lightly damp). Place it within an airtight container, and refrigerate. It’s best to store it in the vegetable crisper drawer in the refrigerator.
To keep for 5+ days
Trim the woody ends from the stems. Snap one spear, and it should break off naturally at the right point (usually about 1-1 ½ inches). You can use that as a guide to line up the remaining spears (or keep them within their rubber band) and trim them in one go.
Transfer the trimmed asparagus to a large glass or jar with an inch of fresh, cold water at the bottom. I also like covering it loosely with a plastic bag to keep away dust/odors.
Transfer the glass/jar to the fridge and replace the water with fresh water every 1-2 days.
Notes
You can use all types of asparagus: Not just green. These tips work for white or purple asparagus and spears of all thicknesses.
Save any scraps: The woody ends can be added to a freezer bag of veggie scraps to turn into vegetable stock or asparagus end soup.
Change the water: I prefer to change it every 2 days. Make sure to change it if it starts looking cloudy, and check on the veggie's freshness at the same time.
Don't store in a cold spot: I like to place the wrapped asparagus in my crisper drawer and the upright "flower vase" ones at the front of the 2nd or 3rd shelf (not the top shelf) in my fridge. Keep it away from the very back/cooling system; otherwise, it can freeze and become mushy.
Don't overcrowd: It’s best if the spears have a little room to breathe, so split the spears between several jars if needed.
Only wash before cooking: If you wash it before storing and don't thoroughly dry the spears, it can lead to premature spoiling.
Keep the stems moist: This is important as the longer they dry out, the more you’ll need to trim from the bottom.