Growth Rate and Nutrient Uptake of Basil in Small-scale Hydroponics

Abstract

<jats:p>To identify practices that may simplify the use of small-scale hydroponic systems for indoor gardening, we compared two nutrient solution management treatments for basil (<jats:italic>Ocimum basilicum</jats:italic>) production. Experiments were conducted for 8 weeks to evaluate the effect of biweekly replacement of the nutrient solution (W) vs. biweekly fertilizer addition without nutrient solution replacement (W/O) on growth and nutrient uptake of basil ‘Genovese Compact’ grown in either a greenhouse or an indoor environment. Greenhouse day/night temperature was 29/24 ± 4 °C, relative humidity (RH) was 65 ± 4%, and daily light integral (DLI) was 26.1 mol·m<jats:sup>‒2</jats:sup>·d<jats:sup>‒1</jats:sup>. The indoor environment had a constant ambient temperature of 21 °C, RH of 65%, and DLI of 9 mol·m<jats:sup>‒2</jats:sup>·d<jats:sup>‒1</jats:sup> provided by broadband white lamps. Four plants were grown in 7.6-L replicate hydroponic systems, with 178 mg·L<jats:sup>‒1</jats:sup> N from a complete nutrient solution in two experimental runs. Shoot fresh and dry mass, leaf number, and leaf area showed an increasing quadratic trend over time when plants were grown in the greenhouse. In contrast, growth over time was linear for plants grown indoors. Within each environment, solution management treatment did not affect growth, indicating that the simpler W/O strategy was adequate under these conditions. Plants grown in the greenhouse required more frequent refill water applications compared with indoors, which resulted in three to four times more refill water applied. Because indoor-grown plants had a decreased growth rate, nutrient uptake rate, and volume of water applied compared with plants grown in the greenhouse, electrical conductivity (EC) for the W/O treatment increased over time. Final nutrient solution concentration was highest for indoor-grown plants under the W/O treatment, and final tissue nutrient concentration was higher for plants grown indoors compared with the greenhouse. Final nutrient uptake (dry mass × nutrient concentration) was higher for plants grown in the greenhouse rather than indoors. Considering that EC increased in the solution of indoor-grown plants under W/O, an appropriate strategy using this treatment would require reducing fertilizer input indoors. To refine simple and robust fertilizer management strategies for indoor gardeners, further research is needed to test variables such as different plant species, cultivars, and water qualities.</jats:p>

Complementary Nutrients in Decoupled Aquaponics Enhance Basil Performance

“…Contradictions between nutrients concentrations in leaf tissue and solution were apparent and inconsistent with visual observations. Leaf tissue nutrient concentrations can be used to evaluate deficiencies [30,31]. In leaf tissue, nutrient concentrations in DAP+ did not differ or were less than DAP, but in solution, concentrations in DAP+ did not differ or were greater than DAP (Table 3, Figure 4).…”

Effects of Nutrient Solution Management and Environment on Tomato in Small-scale Hydroponics

“…In contrast, different management strategies could be used to minimize time, waste, and effort by home gardeners. In a study characterizing growth and nutrient uptake of hydroponically grown basil (Ocimum basilicum) in a greenhouse or indoors under solesource lighting, Solis-Toapanta et al (2020b) showed that within each environment, plants could be grown successfully for 8 weeks without a nutrient solution replacement. However, due to the limited plant growth indoors, excess nutrients accumulated in the solution when it was not consistently replaced.…”

Effects of foliar biofertilization on the Water Use Efficiency in different varieties of basil (Ocimum basilicum L.)

“…Whereas plant growth is a function of environmental parameters, the effect there of is cumulative. It is expected that the plant develops best in optimal conditions of temperatures (Walters & Currey, 2019), with optimal light concentrations (Solis-Toapanta & Gomez, 2019), with optimal water consumption and nutrient availability (Solis-Toapanta et al, 2020). When the system becomes stressed, whether, because of high temperatures or depleted soils, with low contents of organic matter, and therefore, low water storage capacity, the RGR values are low.…”