Nigella seeds commonly used in modern cuisine come from the small and unusual flower Nigella sativa, a member of the Ranunculaceae. It is unusual in being an edible plant in a family with many toxic and irritating members, a sheep among wolves so to speak. Though it holds a prominent place in many Middle Eastern, Indian, and Mediterranean cuisines and is revered as a medicinal plant, nigella is not commonly grown in my region as a food plant. It does have a relative, however, that has become an extremely common annual flower in cottage gardens across the world that also happens to be edible.
Love-in-a-mist, Nigella damascena, is a rather popular garden flower that produces distinctive pods full of oddly flavored seeds. They have an unusual odor all their own, perhaps most reminiscent of nutmeg with a whiff of clove, and a taste that is similar to the smell with a lightly herbal and drying aftertaste. They are also special in that they are quite easy to harvest – not something to be said for every grain or seed. They can be used in baking or as a seasoning, almost like pungent sesame seeds. A lot of sources indicate that neither species should be consumed in very large quantities, as they are supposedly mildly toxic in large amounts, but in actuality both species appear indeed safe to eat and studies have not indicated significant toxicity (studies: 1 2).
I planted a 15 square foot block of N. damascena last fall, around October. It grew, albeit slowly, throughout the winter and sprung to life in spring, shooting up and throwing out scores of gorgeous white and blue flowers hovering in the lacy foliage.
These flowers quickly became devilish spiky balloons where they were neglected for a few months until now: harvest time. Despite sitting around all summer these pods were full of small fragrant seeds, and the small amount of irrigation they were getting allowed new seeds to fall to the ground, germinate, bloom, and create even more pods. All of this with absolutely no fertilization.
Perhaps the best way I have found to harvest the pods quickly is to harvest a bunch of stems and directly cut the pods in half with shears over a bucket. A good shake or two will knock most of the seeds into the bucket and a few swishes of the bucket will let you separate the seeds from the husks, which can easily be removed. The seeds can be further winnowed to clean them, a fairly easy process that can be accomplished by straining through screens and pouring the seed between two buckets from a height of a few feet in front of wind or a fan. Overall a simple and quick process for a decent seed yield.
About 45 minutes of work yielded around a cup of seeds and the plot is not fully harvested, with about half of the plants still remaining. If we are assuming I can get another half a cup out of the plot, which seems likely, the total yield comes out to 1.5 cups per 15 square feet, or .1 cup per square foot. I am being conservative when I say I have harvested 50%, and potential yields could definitely be higher. Assuming a similar caloric count to sesame this comes out to about 80 calories per square foot, not a terrible yield for a little flower that can be planted in the fall in an unused corner of the garden, or under a fruit tree.
Given the ease of harvesting and the decent yield it seems that nigella seed is a worthwhile food crop for home gardeners, even if only as a spice and condiment. It is not common in grocery stores, either. In the next couple of months I will replant a plot of N. damascena and will be planting another plot of N. sativa seed that I acquired from Select Seed. This way I can compare the flavor and yield of the two and decide which is better eating and easier to grow, as so far N. damascena has exceeded my expectations.