A few years ago, I sent an email to the Portland Permaculture Guild list with these notes on various small seed crops:
Of the small seeds, fennel seed comes the closest to meeting my overall food forest goals,
as a perennial insect nurturing weedy multi-use plant, with seeds
providing good calorie yield per square foot. However, it misses my goal of
being edible in large quantities; I'm eating about 50 calories per day
of it, and don't think I would want to increase that beyond 100-200 at
most. Read a more detailed write-up.
Good King Henry works well as a perennial, decently yielding
low-maintenance seed crop. But it bears seeds even smaller than
quinoa, which require processing to get off the chaff. My limited
experiment suggested the labor time:calorie yield is good, making it
worthwhile to process them if you're serious about growing your own
calories, but it does take a while. GKH seed requires the same sort
of soaking as does quinoa, but I don't find that at all time consuming
or difficult. I find the cooked seeds hearty and delicious, and everyone else who's sampled them has liked them as well.
Sunflower seeds have a lot of potential, though we've had trouble
direct seeding due to slug pressure, and we've consistently failed to
harvest and/or process the seed heads in the autumn to actually eat
Favas and early peas also have a lot of potential for us in
winter-rain Mediterranean climates, though again we've had trouble
with slug pressure. Our slug problem also means we've yet to successfully
grow, let alone overwinter, scarlet runner beans, but I'd love to get
that going as a perennial large-seeded legume.
We've been growing evening primrose (Oenothera biennis) as a root,
leaf, flower, and seed crop, but I find the seeds pretty much
unusable. They're easy enough to harvest, but they're so tiny that I
can't run them through our grain grinder or just sprinkle them on food
and expect to crush them up in the course of eating. I have to
deliberately eat a pinchful at a time and chew them up really well.
Sadly, the seeds have no flavor at all; it's like eating tiny crunchy
nothingness. I don't enjoy eating tiny crunchy nothingness, so I've
given up on these as a seed crop.