Timing and Rates of Two Products Using Hydrogen Peroxide (H2O2) to Control Algae in Ebb and Flow Hydroponic Systems

Abstract

Algae is not desirable in hydroponics and creates problems such as reduced yield and decreased dissolved oxygen, and affects the physiology of plants and, thus, needs to be controlled. An experiment was conducted in Ebb and Flow hydroponic systems to investigate the application timing and rates of two hydrogen peroxide products (Zerotol and PERpose Plus). Treatments included 35 mL weekly, 35 mL biweekly, 70 mL weekly, 70 mL biweekly, and a control with no application of hydrogen peroxide using a 40-gallon reservoir of water. Pepper ‘Early Jalapeno’ and ‘Lunchbox Red’ and tomato ‘Geronimo’ and ‘Little Sicily’ were used. The study was conducted in a split-plot design with two replications over time. Plant growth parameters, including plant height, flower number, net CO2 assimilation, fresh weight, and dry weight were recorded. Algae data, including dry weight, algae cell counts, and chl a were also measured. Results indicated that with increasing rate and timing of either product decreased algae counts, dry weight, and chl a values. However, weekly and biweekly application of 70 mL of both products were not different for algae quantification. In pepper, plant height, shoot fresh and dry weight, and root fresh and dry weight were found to be significantly greater with Zerotol 35 mL biweekly, Zerotol 70 mL weekly, PERpose Plus 35 mL biweekly, and PERpose Plus 70 mL weekly compared with the control. ‘Lunchbox Red’ was significantly greater than ‘Early Jalapeno’ in all growth parameters, except soil plant analysis development (SPAD). ‘Lunchbox Red’ had the greatest flower number, with weekly application of 70 mL PERpose Plus. In tomato, greatest flower number and SPAD were observed in ‘Geronimo’ with a weekly application of 70 mL PERpose Plus and 70 mL Zerotol, respectively. Greater shoot and root fresh and dry weight for both tomato cultivars were recorded with 35 mL biweekly or 70 mL weekly application with either product. The results from both plants as well as algae analysis suggest that weekly application of 70 mL of either Zerotol or PERpose Plus produced the best results in terms of controlling algae and improving the growth of pepper and tomato plants.

Effects of Hydrogen Peroxide Products on Basil, Lettuce, and Algae in an Ebb and Flow Hydroponic System

“…Similarly, Schumann et al [55] found that mechanical homogenization improved extraction up to 20%, but chlorophyll-a extraction efficiency was strongly species-specific and influenced by the growth conditions. Thakulla et al [39] reported similar algae species as those found in this study, with Chlamydomonas spp. found in all treatments, and Gleocystis vesiculosa found in greater concentrations in most treatments.…”

“…Similar to our findings, Lau and Mattson [36] found that greater levels of hydrogen peroxide stunted root and shoot growth significantly more than the control and lower concentrations of hydrogen peroxide in lettuce. Thakulla et al [39] found that lower amounts of hydrogen peroxide products applied weekly can help increase height, shoot DW and root DW, but greater concentrations applied weekly or biweekly decreased significantly in the biomass and height of tomatoes. Deng et al [40] reported similar findings in sweet potato (Ipomoea batatas L.) seedlings with concentrations of less than or equal to 2.5 mM of exogenously applied hydrogen peroxide reported having positive effects on seedling growth and root formation, while treatments that exceeded 5 mM of hydrogen peroxide had the opposite effect.…”

“…Rates as low as 12.3 mg L −1 hydrogen peroxide combined with 8 mg L −1 peracetic acid to control algae to 185 mg L −1 hydrogen peroxide plus 120 mg L −1 peracetic acid with 1 min contact time are recommended to control some pathogens [38]. Thakulla et al [39] found that concentrations of 70 mL of ZeroTol or PERpose Plus applied biweekly to 40-gallon tanks significantly decreased algae concentrations. Because of its strong oxidizing abilities, hydrogen peroxide produces hydroxyl radicals under light exposure, which destroys proteins, lipids, and DNA, severely damaging unicellular organisms [44,45].…”

Microbial Analysis and Sanitization of Hydroponic Farming Facilities in Singapore

“…Although a time-dependent effect was observed within all tested components resulting in significant reductions (P < 0.05), 2.3-3.9 Log CFU/cm 2 of microbial counts were still obtained after treatment by 3% H 2 O 2 for 12 h (Table 1). H 2 O 2 has been gaining high popularity among hydroponic growers due to the free concern over the chemical residuals, leading to many studies evaluating its efficacy (30)(31)(32)(33)(34) and commercial companies providing H 2 O 2 -based hydroponic decontamination solutions such as Waterco from Australia. Furthermore, the literature also extensively documented the potential role of H 2 O 2 as a signaling molecule in abiotic stress response and photosynthesis, contributing to growth performance in plants (35)(36)(37) and thus further enhancing the appeal of H 2 O 2 for hydroponic growers.…”

“…2 of microbial counts were still obtained after treatment by 3% H 2 O 2 for 12 h (Table1). H 2 O 2 has been gaining high popularity among hydroponic growers due to the free concern over the chemical residuals, leading to many studies evaluating its efficacy(30)(31)(32)(33)(34) and commercial companies providing H 2 O 2 -based hydroponic decontamination solutions such as Waterco from Australia. Furthermore, the literature also extensively documented the potential role of H…”