Equipment Modifications for Harvesting Fluffy Seeds

Abstract

Fluffy seeds of native wildflowers are difficult to harvest using traditional equipment and methods. We modified intake and storage on a tractor-drawn leaf vacuum machine to better harvest fluffy seeded species such as aster (Aster L.[Asteraceae]) and narrowleaf silkgrass (Pityopsis graminifolia (Michx.) Nutt.[Asteraceae]). By inserting collection bags inside the vacuum and creating a vacuum hood to ride over the rows of plants, only 1 person is needed for the harvest process. The modified equipment allows us to make repeated harvests over the several-week ripening period and it removes only ripe seeds from the plants. a t the USDA NRCS National Plant Materials Center in Beltsville, Maryland, we produce seeds of many types of wildflowers and native grasses. Some species we work with are easily harvested with a combine; others, however, are not. In particular, light-seeded species with hairy pappus on their seeds, such as asters (Aster L.[Asteraceae]), goldenrods (Solidago L.[Asteraceae]), and narrowleaf silkgrass (Pityopsis graminifolia (Michx.) Nutt.[Asteraceae]) are very difficult to combine. To make matters more complicated, their seeds ripen over a period of several weeks, and a one-time harvest pulls ripe and unripe seed off together (with the possible loss of some already matured seeds).Our previous method for harvesting these types of seeds was to cut the stems of nearly ripe seeds with a sickle bar, spread out stems on a tarp to let seeds mature, and then release seeds by tossing the stems in the air with a pitchfork or rubbing the stems over wire screens. This seed harvest and extraction process required several steps, a large space for spreading out stems, and still resulted in the harvest of some immature seeds. Other harvest equipment options we considered included variations of a vacuum-brush seed stripper, but these machine were expensive, tended to strip the whole seed head instead of just pulling off the ripe seeds, and resulted in some stems, leaves, and other chaff

Pityopsis - Silkgrass

“…Silkgrass is readily propagated by seed. Seeds should be collected after they ripen and turn black when they are most easily removable from the flower head (Kujawski, Englert, and Dusty 2001). Seeds typically ripen and mature in Florida from late October to December; southern populations may ripen later into January.…”