Celery is a biennial plant. That means that it won’t flower until the second year. Celery will winter over in milder areas and produce new stalks in the spring. In areas with cold winters, celery can be dug up and kept in pots in a cool, moist dark area such as a root cellar, then planted back out in the garden in spring. In the second year, the central stalk will thicken and an umbel, or umbrella shaped flower, will appear. The umbel is created out of numerous tiny florets on short stems. Each floret is a tiny white flower that collectively creates a burst of stars. Bees and butterflies are quite taken with the blooms, which resemble Queen Anne’s lace. Wait until the seeds dry and turn tan to brown before celery seed harvesting. The swollen ovaries develop a carapace that is hard when ripe and the color deepens. The seeds will have vertical ridges around the edges that are lighter in color than the rest of the seed. You know it is time to harvest when the seeds fall off at the slightest touch or breeze. Harvesting celery seeds with the most flavors relies upon careful observance to ensure the seed is ripe. When the flower head is dry and the individual seeds are hard and dark colored, cut the bloom carefully and shake the seed into a bag. Alternatively, bend the flower stalk into a bag and shake. This reduces the seed lost during cutting the head. To save whole seeds, pick out any flower debris and make sure seeds are dry before packing them into a container. Place seeds in a glass container with a tight fitting lid.Label and date the seeds. Store the seeds in a cool, dark location for up to 5 years. Celery seed is a popular seasoning especially for pickles. Most cooks use celery seed whole but you can also choose to grind it. Use a coffee grinder or mortar and pestle to make fresh ground celery seed, which disperses more evenly in a dish. Celery seeds add a zesty flavor to sprouting and micro-green mixes.