There is a growing interest in the production of hemp for the extraction of cannabidiol (CBD) due to reported therapeutic benefits. Recent policy reform has permitted state hemp pilot programs, including the land grant research institutions, the ability to investigate the potential of growing and harvesting Cannabis sativa plants (≤0.3% tetrahydrocannabinol) for these purposes in the U.S. There are vast gaps of knowledge regarding the fertility requirements of hemp cultivars grown in a horticultural production setting for floral attributes such as the cannabinoid constituents. Foliar tissue analysis provides an avenue to determine adequate ranges for nutrient uptake and estimating fertilizer requirements prior to visual symptoms of deficiency or toxicity. To facilitate a survey range of elemental nutrient acquisition in hemp cultivars propagated for CBD production, foliar analysis was executed using the most recently mature leaves (MRML) of mother stock plants. All plants were maintained in the vegetative stage for twelve weeks, prior to initiation of cutting for clone harvesting. A total of thirteen cultivars were utilized to broaden previously reported baseline survey ranges. Significant differences were found among all thirteen cultivars in accumulation of both micro and macro essential nutrients, widening the range of the fertility requirements of Cannabis plants grown in this production model for CBD harvesting.

Sunflower (Helianthus annuus L.) is a commercially important cut flower requiring research into postharvest factors such as recutting, water uptake, stem number, cooling rate, and storage temperature to maximize vase life. Stems of ‘Sunbright’ sunflower were either recut before or after a drying period up to 48 hours. Water uptake, stem quality, and microbial counts were determined 4 days after rehydration. Water potential was determined by five corresponding leaves per treatment. Effects of stem number per vase were evaluated with either one, three, five, or ten stems. Effects of cooling rate were determined by temperatures of 5 ºC for 3 days in the dark, 5 ºC for 2 days in the dark preceded by 24 hours at either 20 ºC with light or 32 ºC in a shaded area outdoors or were maintained in a shaded area 32 ºC for 3 days. Hydration and storage temperature effects were determined by either transfer to a postharvest environment, 20 ºC cooler for 2 hours, immediate storage for 2 days at 5 ºC or 3 days at 5 ºC after recutting the basal stem. Allowing stems to dry up to 48 hours reduced vase life by 2.3 days or less. Vase life was unaffected by harvesting into water or number of stems in a vase but was affected by temperature such that the longest vase life of 13.2 days occurred when stems were stored for 3 days at 5 °C + 0.5 ºC followed by postharvest evaluation at 20 °C + 1 ºC.

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Six experiments were conducted using three cultivars to investigate the impact of water electrical conductivity (EC) and the addition of nutrients to vase solutions on postharvest quality of cut rose (Rosa hybrids) stems. Postharvest quality of cut ‘Freedom’ rose stems was evaluated using solutions containing either distilled water with sodium chloride (DW+NaCl) or DW+NaCl with the addition of a commercial floral preservative (holding solution containing carbohydrates and biocide) to generate a range of EC values (Expts. 1 and 2). The third experiment compared the effect of different EC levels from the salts NaCl, sodium sulfate (Na2SO4), and calcium chloride (CaCl2). The fourth experiment investigated EC’s impact on rose stems with the addition of two rose cultivars (Charlotte and Classy). When ‘Freedom’ stems were subjected to DW+NaCl, the longest vase life was achieved with 0.5 dS·m–1. The addition of holding solution not only extended vase life but also counteracted the negative effects of high EC with maximum vase life occurring at 1.0 dS·m–1. Furthermore, stems in the holding solution experienced significantly less bent neck and the flowers opened more fully than those in DW. Stems placed in DW with a holding solution also experienced more petal bluing, pigment loss, necrotic edges, and wilting than those held in DW alone. This effect was likely due to increased vase life. Salt solutions containing Na2SO4 and CaCl2 resulted in extended vase life at 1.0 dS·m–1, but increasing salt levels decreased overall vase life. As EC increased, regardless of salt type, water uptake also increased up to a maximum at 0.5 or 1.0 dS·m–1 and then continually declined. Maximum vase life was observed at 1.5 dS·m–1 for cut ‘Charlotte’ stems, and at 1.0 dS·m–1 for ‘Classy’ with the addition of a holding solution. Physiological effects were different based on cultivar, as observed with Charlotte and Freedom flowers that opened further and had less petal browning than Classy flowers. ‘Freedom’ had the greatest pigment loss, but this effect decreased with increasing EC. Further correlational analysis showed that in water-only solutions, initial and final EC accounted for 44% and 41% of the variation in vase life data, respectively, whereas initial pH accounted for 24% of variation. However, the presence of carbohydrates and biocides from the holding solution was found to have a greater effect on overall vase life compared with water pH or EC. Finally, in Expts. 5 and 6, cut ‘Freedom’ stems were subjected to DW solutions containing 0.1, 1, 10, or 100 mg·L–1 boron, copper, iron, potassium, magnesium, manganese, or zinc. None of these solutions increased vase life. Conversely, 10 or 100 mg·L–1 boron and 100 mg·L–1 copper solutions reduced vase life. Finally, the addition of NaCl to a maximum of 0.83 dS·m–1 increased the vase life in all solutions. These analyses highlight the importance of water quality and its elemental constituents on the vase life of cut rose stems and that the use of a holding solution can overcome the negative effects of high EC water.