The smallest measuring spoons were designed to fit just-one-seed, even for pretty small seeds:
Lee Valley Seed Spoon (R)
http://www.leevalley.com/en/ga...
Edited to add ...
Lee Valley and every other vendor reported "out of stock, so I asked Rittenhouse, and got a very prompt reply:
Dear Richard,
The Seedspoons were not ours. We did sell them but the company stopped making them years ago. We have none left. We do not know of anyone selling them.
Thank you,
Bruce
Bruce Zimmerman GWA HTD LICRH
Consumer Products Manager
M.K. Rittenhouse & Sons Ltd.