Optimizing Hydroponic Strawberries

Hydroponics is an alternative process of growing plants using water rather than relying on soil and chemicals to optimize its growth and quality with the strawberry plants. Alternative methods were proposed to lessen waste, chemicals, balance moisture, and improve aeration. The study investigates the effectiveness of sawdust, coco soil, and pumice given that sawdust was relatively cheap; coco soil offers adequate moisture levels; and pumice improves drainage. The scientists hypothesized that there needs to be a specific ratio of biodegradable matter to improve growth, production, and quality of the fruit and plant.

Figure one represents the organic matter that can be used to optimize the production of hydroponically grown strawberries. After week 6, the number of leaves differed among the substrates. Coc-100 had the greatest influence on the leaf production because the number of stolons increased up to 70% in plants grown compared to the other respective plants. The Coc-100 was grown in “different cultivars and under different growth conditions.” The fresh weight of the leaf and stem were increased for the Coc-100 compared with the Saw and Pum.

Figure 2 shows the relationship between stolon development from weeks 2-8 and fruit production from weeks 8-12 based on six substrates: 100% pumice (Pum-100, control), 100% sawdust, 100% coco soil, and three mixtures of pumice, sawdust, and coco soil. The independent variables were the substrate types, while the dependent variables were the number of stolons and fruits produced. During the early stages, Coc-100 had the highest stolon count by week 8, with about 4 stolons per plant. The mixed substrates, especially Coc-Pum 50-50, showed mixed results due to coco soil's ability to retain moisture and pumice’s ability to improve drainage. In weeks 8-12, Pum-100 produced nearly 3 fruits per plant, while coco soil produced fewer. Mixed substrates had better performance, indicating the benefits of using coco soil for improved early stolon development, and using pumice to improve the quality of fruit production.

Figure 3 shows the relationship between the six substrates’ leaf photosynthetic rates; stomatal conductance; and intercellular CO2 concentration in fully expanded leaves of hydroponically grown strawberries. The independent variables were the types of substrates, while the dependent variables included the rates of photosynthesis, stomatal conductance, CO₂ concentration, and environmental conditions. The photosynthetic rate was highest around week 6 for Coc-100 (17 μmol/m²/s) and Pum-100 (15 μmol/m²/s). Stomatal conductance was at 0.5 mmol/m²/s for Coc-100 while Pum-100 was 0.3 mmol/m²/s. Intracellular CO₂ levels were highest with Coc-100 and Coc-Pum 50-50 at about 300 μmol/mol, while Pum-100 had the lowest at around 260 μmol/mol. The researchers concluded that coco soil improved better moisture retention and nutrient levels, and the quality of the leaves for optimal strawberry production.

The researchers’ findings showed that mixed plants that contained coco were a better source for producing strawberries due to better moisture control and nutrient levels. Plants that had a mixture of coc-100 had healthier leafs, stolons, and fruit production. Sawdust decomposes, not allowing it to retain the nutrients. Pumice had higher drainage, less water, and nutrient retention, while sawdust was tightly compacted. This study shows that an ideal balance between soil quality, moisture retention, and nutrient exposure will lead to better hydroponic cultivation.

Marinou, E., Chrysargyris A., & Tzortzakis N. (2013). Use of sawdust, coco soil and pumice in

hydroponically grown strawberry. Plant Soil Environ, 59(10), 452-459.

10.17221/297/2013-PSE.