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greenhouse industry is shifting away from solely producing herbaceous ornamental crops and integrating or replacing these crops with vegetables and herbs. For this reason, hydroponics and other systems using recirculated nutrient solution have become an

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anaerobic respiration. Oxygenation in Hydroponics Plant growth has been shown to increase when irrigated with additional dissolved oxygen (DO) in the solution ( Soffer et al., 1990 ), therefore, in hydroponics it is important that oxygen is dissolved in the

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level for being considered as a replacement to HPS lamps in hydroponics growth environments. LED lamps are anticipated to replace HPS lamps in most applications as a result of their reduced electricity consumption, improved quality of light, and the

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Many people want to use hydroponics in production of plants but often are hobbyists with limited access to the reagents necessary to formulate a nutrient solution. Several readily available commercial fertilizers and chemicals with tomato-(Lycopersicon esculentum Mill.) as the test plant were used to develop a nutrient solution. A 20-8.8-16.6 IN-P-K) general purpose fertilizer was added (1 g/liter) to deionized water to make a basic solution. This solution was fortified with slow-release fertilizer (approx. 17N-2.6P-8.5K with Ca, Hg, and minor elements) at 1 g/liter added directly to hydroponics vessels. Tomato developed severe foliar symptoms of Ca deficiency in this medium. Addition of CaSO4 or CaCO3 at 0.5 or 1 g/liter to give a solid phase of these chemicals in the vessels prevented development of symptoms of Ca deficiency; however, plants now showed symptoms of Mg deficiency. Addition of MgS0 at 0.25 g/liter to the basic solution prevented symptoms o Mg deficiency. Analyses confirmed that leaf N, P, K, Ca, and Mg were sufficient.

This solution was as good as Hoagland's No. 1 solution for growth of tomato, marigold, and cucumber and was better than Hoagland's solution for growth of corn and wheat.

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hydroponic conditions ( Souret and Weathers, 2000 ), to increase overall production and produce saffron out of its natural season. Souret and Weathers (2000 ) suggested that both aeroponics and hydroponics could be used for growing saffron corms as a

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closed hydroponics system by the biossay with cucumber seedlings Soc. High Tech. Agr. 10 92 95 (in Japanese with English summary). Asao, T. Taniguchi, K. Tomita, K. Hosoki, T. 2001 Species

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NASA has investigated the use of recirculating nutrient film technique (NFT) systems to grow higher plants on long-duration space missions for many years and has demonstrated the feasibility of using recirculating systems on numerous crop species. A long duration (418-day) experiment was conducted at Kennedy Space Center, Fla., to evaluate the feasibility of using recirculating hydroponics for the continuous production of Solanum tuberosum L. `Norland'. The productivity of four sequential batch plantings was compared to staggered harvest and plantings. The accumulation of bioactive organic compounds in the nutrient solution resulted in reduced plant height, induced early tuber formation, and increased harvest index of the crops in both production systems. The changes in crop development were managed by increasing planting density and reducing cycle time to sustain production efficiency.

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Tuskegee University is conducting research on salad crops as part of the National Aeronautics and Space Administration's (NASA) goal of supporting humans on near-term space missions, such as on the International Space Station. Small areas of salad crops are ideal candidates for growing in limited volumes, and would provide a source of fresh food to enhance the crew's nutrition. Baseline controlled environment studies were initiated to evaluate the response of eight carrot cultivars (`Baby Mini', `Nantes Touchan', `Danvers 126', `Kundulus', `Nanco Hybrid', `Thumbelina', `Early Nantes', and `Juwarot') to growth and yield in hydroponics. Seeds were sown in moist arcillite and transplanted into growth troughs (0.15 × 0.15 × 1.2 m) after 18 days in reach-in growth chambers, and nutrients continuously supplied by a half-Hoagland solution. Growth chambers conditions included 300 μmol·m-2·s-1 photosynthetic photon flux, 16/8 photoperiod, a constant 25 °C and relative humidity of 50%. Plants were harvested at about 80 days. All eight cultivars grew well in the hydroponic system. Seven cultivars produced greater shoot fresh than root mass except `Baby Mini', which showed the reverse. `Danvers 126', followed by `Nanco Hybrid' and `Nantes Touchan', produced highest root yields. The β-carotene content varied by cultivars. The highest level of 10,400 IU/100 g was obtained for `Thumbelina', followed by `Baby Mini' (8040 IU/100 g), `Juwarot' (6160 IU/100g), and `Early Nantes' (5210 IU/100 g), and the lowest by `Nantes Touchan' (3510 IU/100 g). These results show that while carrots adapted well to growth in hydroponics, carotene, a major nutrient, was at relatively low levels.

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Environmental conditions are known to affect the growth and quality of culinary and medicinal herbs. Hydroponic growing conditions often produces greater yields for many leafy crops compared to growth in more-traditional media. The objective of this investigation was to compare the yield and quality of sweet basil grown in continuous flow solution culture or well-irrigated Universal Mix. Sweet basil plants were germinated under mist and then transplanted to a continous-flow hydroponics system or to 6-inch pots containing Universal Mix. Rows of pots alternated with a row of hydroponic plants in a temperature-controlled greenhouse. Temperatures were maintained between 20 and 25 °C, the relative humidity was not controlled, pot-grown plants were irrigated as needed. HID lights added sublimentry irradiation and maintained a photoperiod of 18 h. Cohorts of plants were harvested at five time points between transplanting and maturity. Plants were divided into leaves, stems, and roots, dried, and the data subjected to mathmatical growth analysis. Several leaves from each plant were harvested and analyzed by gas chromotograpth for essential oils. Plants grown in hyroponics grew faster and produced more harvestable leaf material than the media-grown plants. Details of the plant growth analysis and the essential oil composition will be presented.

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Concentrations of culture solution in hydroponics were changed for the purpose of improving the quality of herbs. Culture solution containing Ca(NO3)2·4H20:45g. KNO3:36g. MgSO4·7H20:22. 5g. NH4H2PO4:6. 75g, and Fe-EDTA:6. 67g in \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(45{\ell}\) \end{document} water was defined as 1 unit solution.

Japanese honewort (Cryptotaenia japonica Hassk). soup celery (Apium graveolens L. var. dulce DC.). and parsley grown with 2 unit solution showed higher contents of ascorbic acid(ASA). phenols, free amino acid, and chlorophyll than those grown with 1 unit, but they showed lower yields and shorter shelf lives. Lowering the concentration of solution to 2/3 unit resulted in the increase of yield of peppermint, sage, basil, and perilla (Perilla frutescens Britton) and the decrease of ASA and chlorophyll contents. Shelf lives of berbs with 2/3 unit were longer than those with 1 unit. The smell of herbs tested in this experiment was not affected significantly in sensory test by the change of concentration of solution.

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