Use of Sieved Compost Plus Hydrogel for Solid Matrix Priming of Native Wildflower Seeds

Seeds of dense blazing star [Liatris spicata (L.) Willd.], smooth blue aster (Aster laevis L.), purple coneflower [Echinacea purpurea (L.) Moench], and Oxeye sunflower [Heliopsis helianthoides (L.) Sweet] were solid matrix primed in a carrier containing fine particulate yard and greenhouse waste compost blended with hydrogel (SuperSorb F; Aquatrols Corporation, Paulsboro, NJ) and distilled water at seed:carrier ratios of 1:6 or 1:30 for 9 d at 15 ^oC in darkness followed by seed drying (room temperature with air-flow for one week).  The compost based carrier allowed percentage water content of 228% and 138% (dry weight basis), respectively, during priming matric potentials of -0.5 MPa and -1.0 MPa.  Seed germination testing at 20-30 ^oC (14-10 h; 106 µmol∙m^-2∙s^-1 of light at the warmer temperature) indicated that priming decreased days to 50% germination 31-61% and increased final germination percentage (FGP) 18-63%, compared to nontreated seed.  Following priming with 1:6, rather than 1:30, seed:carrier at -0.5 MPa or -1.0 MPa, smooth blue aster seed germinated more rapidly than nontreated seed.  Except for smooth blue aster, both low and high seed:carrier ratios at either matric potential decreased days to 50% germination compared to nontreated seed.  All solid matrix priming treatments increased FGP compared to nontreated seed except for 1:6 seed:carrier at -0.5 MPa (dense blazing star, purple coneflower, and smooth blue aster), for 1:6 seed:carrier at -1.0 MPa (purple coneflower), and for 1:30 seed:carrier at -0.5 MPa (smooth blue aster).  In conclusion, a compost based carrier system has potential as an inexpensive solid matrix priming technique for increasing seed performance of native wildflower seed.