1bunch of asparaguswoody ends discarded (spears should fit into a quart mason jar with a good inch of headspace at the top. Trim up the ends if you need to accommodate this)
Dissolve the sea salt into the warm water and set aside. This is your brine to pour over the asparagus later.
Put the garlic, mustard seeds, dill, and red pepper flakes into a clean, 1 quart mason jar. Then the pack the asparagus spears into the jar as tightly as you can.
Pour the salt water brine over the packed in asparagus and spices, leaving 1 inch of headspace at the top. Be sure the asparagus is completely submerged under the brine (I like to use a weight, like this Pickle Pebble to keep the veggies down).
Seal your jar with your fermenting seal of choice. I use these Pickle Pipes<. See the above section about sealing options.
Let the sealed jar sit at room temperature until the taste is to your liking, anywhere from 1-3 weeks. You can taste them every few days to see where they are at. Remember that if you live in a warm climate, the fermenting will go faster. It is still quite chilly up here, and so my veggie ferments take more like 2-3 weeks to get to where we like them.