Peat moss is a major component of many plant growing substrates but is quickly becoming a limited resource. To reduce the reliance on peat moss a number of composted products, including pine mulch, manure, yard waste and aged bark - in combination with peat moss and/or coconut coir, were mixed in various combinations as growing substrates for greenhouse potted Gerbera (Gerbera jamesonii) production. Four new substrates were developed and compared to a commercial mix, BM6 in greenhouse production trials. Experiments were conducted to (1) compare the plant growth and quality of potted Gerbera in the newly developed substrates to BM6, (2) determine whether a pre-charge fertilizer was needed for the newly developed substrates, (3) determine appropriate rates of a pre-charge fertilizer for the newly developed substrates, and (4) determine the nitrogen drawdown index over the time of production and determine if there is a relationship between the NDI values and the nitrogen availability measured by pour through values. Two of the newly developed peat reduced substrates were successful in producing acceptable quality potted Gerbera. One of the substrates contained a low percentage of peat moss and the other contained coir fines. Fertilizer pre-charge rates, and some nutrient and irrigation management protocols were recommended for these two substrates.

Sustainable landscaping includes utilization of plants requiring few inputs. We chose four species showing potential for use in arid landscapes: Purshia mexicana, Shepherdia argentea, Shepherdia rotundifolia, and Alnus maritima. We sowed seeds of S. rotundifolia, S. argentea and P. mexicana in three substrates with various water-holding properties due to differing amounts of organic matter (OM). S. rotundifolia germination was maximized in a calcined clay (66.2%) containing no OM and had low germination (12.7 - 21.8%) in the other substrates. S. argentea germination (42.3 to 53.7%) was similar in all substrates. Poor seed quality of P. mexicana resulted in inconclusive results. Our results suggest that germination of some species is enhanced by substrates with excellent drainage properties. We also investigated effects of different rates of controlled-release fertilizer (CRF) on symbiotic nodule formation in seaside alder. We found that lower than prescribed rates of CRF enhanced nodulation without compromising nitrogen status.