Production of High Quality Potted Organic Violas (Viola tricolor) in Peat and Compost Based Substrates Supplemented with Liquid Fertilizers

As organic foods become ever more popular, there has been increased interest in expanding organic production to include specialty crops.  Viola flowers are sold as culinary garnishes or salad components so there is the potential for marketing organic viola flowers as a niche market crop.  This factorial study included 3 Organic Materials Review Institute (OMRI) certified organic peat-based substrates with compost added as a source of organic nutrients (Fafard FOF 30, Fertrell special mix, and Sunshine #1 natural & organic) and 3 OMRI certified liquid fertilizers which consist of proprietary blends including oilseed-extract, fish hydrolysate, fish emulsion, and/or kelp extract (Daniels Pinnacle 3-1-1, Drammatic K 2-5-0.2, and Fertrell Liquid #1 4-1-1). A control group which received no fertilizer was planted in each substrate. Conventional control groups were included in a conventional peat-based substrate (Fafard 2) with or without conventional fertilizer (Peter’s 20-10-20).  In all fertilized treatments 150 mg∙L^-1 nitrogen was supplied as a constant liquid feed.  Organically produced viola seed (Viola tricolor ‘Helen Mount’) were sown directly into 4-inch pots on 21 Sept.  Substrate pH and electrical conductivity (EC) were measured every 14 days.  At the end of the experiment each plant was rated for quality on a 1 to 5 scale and shoot fresh and dry weights were recorded.  All treatments which received either organic or conventional fertilizer were deemed marketable (a rating of 3 or higher) at the termination of the experiment 82 days after sowing.  The shoot fresh and dry weights of plants grown with organic substrate and fertilizer combinations were not different from those grown with conventional fertilization with one exception.  Plants grown in the Fertrell substrate and fertilized with Fertrell Liquid #1 were 13% heavier than the conventional control plants by both fresh and dry shoot weight.  All plants grown without fertilizer were not of marketable quality.  This indicates that the incorporated nutrient sources in the substrates are not sufficient for viola production.  The pH and EC values were consistent for the duration of the experiment.  For all fertilized treatments the pH and EC ranged from 5.75–6.60 and 1.13–2.75 mS/cm, while unfertilized treatments ranged from 6.50–6.60 and 1.01–1.40 mS/cm, respectively.  These data indicate that organic viola plants of comparable size and quality can be produced on the same schedule as their conventionally fertilized counterparts.