Short Title: Bucket Culture with Sure to Grow® Loose Fill Media
Source/Author/Date: Dr Lynette Morgan PhD, Suntec International Hydroponic Consultants, New Zealand, November 2008
Long Title: A Comparison of Sure to Grow® Pads to 3 Other Growing Media for Production of Wheatgrass in a Standard NFT Tray Greenhouse System, Including Relative Growth rate Analysis and Postharvest Assessment, Arugula, Red Cabbage and Broccoli
The primary objective of this study was to compare the growth of wheatgrass sown into 4 different pad/media products used in US commercial production, these being Cornell Peat-Lite Mix, horticultural grade perlite and vermiculite and the Sure to Grow® Pads.
Links: Suntec
The main findings of this trial were: Perlite consistently performed the poorest of all 4 media evaluated in terms of plant growth rate and yield. Perlite plants were shorter and due to the particles on the bed surface, needed to be cut higher up on the plant at harvest, which may have reduced fresh yields. As with relative growth rates, yield differences are affected by planting date as well as by growing media treatment and by the interaction of these variables. Chi square analysis of the yield data showed differences observed in yield were greater than would be expected, so are therefore caused by treatment.
Harvested product quality was inconsistent in perlite – in planting one the wheatgrass was shorter, but darker green than the other treatments and resisted post harvest yellowing. However in planting two, perlite leaf blade yellowing and some tip burn developed in the production system which reduced harvest quality. STG produced the most consistent shelf life results with minimal yellowing and absence of any post harvest rots, although the perlite treatment from planting one had the highest quality at the end of shelf life assessment due to a darker green color.
The vermiculite was the only treatment to experience any root rot disease towards the end of the trial, this may have been due to the high water holding capacity of this media which may have pre disposed the plants to pathogen attack.
Foliar mineral levels did not show any major deficiencies or toxicities between treatments. The Peat-Lite treatment had higher foliage levels of some elements, which is most likely the result of additional fertilisers in the Peat-Lite mix which added to the nutrients applied via the nutrient solution. STG and perlite had low foliar potassium levels in both planting dates, while vermiculite, an inert media, and Peat-Lite which had additions of potassium nitrate in the mix, ran higher than expected levels. These differences are difficult to explain, given the nutrient solution was not recirculated and had sufficient potassium in the formulation for growth and development.
STG had a clear advantage in the efficiency and management of NFT wheatgrass production systems including greatly reduced set up time, ease of irrigation management, and effective control of root zone moisture levels.
Dr Lynette Morgan PhD
Suntec International
Hydroponic Consultants - New Zealand
November 2008