The best results are obtained on light, sandy soil, the crop reaching its full size during the third and fourth years. Harvesting is difficult because the pods ripen unevenly and break up in hot weather, scattering the seeds. They are generally hand picked as soon as they are ripe.
Quality of seed:
The seeds are about the same size and shape as those of vetches, brown, their surface being finely roughened by a delicate net-like system of curved and branched veins.