Submitted to: Southern Nursery Association Research Conference
Publication Type: Proceedings
Publication Acceptance Date: 12/1/2006
Publication Date: 12/1/2006
Citation: Fain, G.B., Gilliam, C.H., Sibley, J.L., Boyer, C.R. 2006. Evaluation of an alternative, sustainable substrate for use in greenhouse crops. Southern Nursery Association Research Conference vol 51 pp 59-61.
Interpretive Summary: This study evaluated a new substrate for greenhouse production of herbaceous annual crops. Results varied with crop produced but indicate there is potential for an alternative substrate composed of processed whole pine trees. This product could prove to be an acceptable and highly economical alternative to traditional peat moss based substrates.
Technical Abstract: Studies were conducted at the Southern Horticultural Laboratory (SHL) in Poplarville, MS and Young’s Plant Farm (YPF) in Auburn, AL. Six to eight inch diameter loblolly pine (Pinus taeda L.) were harvested from a 10 year old planted pine plantation in south Mississippi. The entire tree including needles was feed through a drum chipper. Resulting chips were then further processed using a hammer mill to pass a 3/16”, 1/4”, or 3/8” screen. These products alone, or combined with peat moss at 20 % or 50 % by volume were amended per yd3 with 7 lbs dolomitic lime, 0.75 lbs micromax and 6 lbs Osmocote 15-9-12 Plus (3-4 month formulation). Six inch containers were filled with substrates and 4 plugs (288 cell) were planted into each container for marigold (Tagetes patula ‘Little Hero Yellow’), petunia (Petunia x hybrida ‘Dreams Pink’, and 2 plugs (50 cell) for lantana (Lantana camera ‘Lucky Red Hot Improved’). Plants were greenhouse grown for 28 – 34 days. Plants exhibited similar results at both test locations. At 34 days after potting (DAP) there were no differences in flower number for marigold however with lantana all 100% whole tree treatments had the fewest flowers. Leaf chlorophyll content was not different for petunia, and with marigold and lantana the general trend was an increase in chlorophyll content with an increase in substrate peat moss content. In general plants grown in whole tree substrates were smaller and increased in size with increasing peat moss percentage. At 34 DAP all marigold plants were considered salable. There were no differences for root ratings with any species among any treatment except lantana were minor differences in one of the 10 substrates tested. Results of this experiment indicate that whole tree substrates, especially when combined with peat moss are a potential alternative to conventional greenhouse substrates.