Maximum Yield USA August/September 2019 | Page 43

“ THERE IS POTENTIAL While starting a crop from young roots is more expensive than raising planting stock from seed, it reduces the time to harvest and allows only healthy roots to be selected for planting out. A potentially profitable option for indoor hydroponic growers with limited space is to not grow ginseng for harvest of the mature product (which then needs to be carefully dried before sale), but to propagate from seed and sell only one- to two-year-old roots to other growers. Ginseng seedlings can be grown at a much higher density than mature plants and respond well to hydroponic nutrition — this allows the production of high- health planting stock which has not been in contact with soil and is well suited to further soilless production. Starting with stratified seed which is usually for sale in fall, this needs to be sown a half-inch to one-inch deep, with an average germination rate of 70 per cent. Seed beds containing a mix of fine grade perlite and coconut fiber and a high-quality, low-mineral water source are suitable for the germination process TO IMPROVE YIELDS AND GROWTH RATES THROUGH CLIMATE AND ROOT ENVIRONMENTAL CONTROL AS WELL AS OPTIMAL NUTRITION. ” Top: French tarragon is slow growing but receives high prices on the fresh herb market. Bottom: Ginseng has shown increased root growth when exposed to high concentrations of potassium. Hydroponic Systems for Ginseng Hydroponic systems for ginseng have had limited research, however, there is potential to improve yields and growth rates through climate and root environmental control as well as optimal nutrition. Ginseng requires low light levels (heavy shading is used for outdoor crops) with light saturation occurring in both seedlings and mature plants at about 150 micromoles m-2 s-1 (1) which is around 7.5 per cent of full sunlight. Too much light will reduce yields, burn leaves, and lead to plant decline, while excess shade depresses the yield potential. Much of the photo assimilate produced by the ginseng leaves ends up in the thickened root system, however, the yield of the roots can be increased by up to 25 per cent if the flowering stems are removed as they form. Temperatures for ginseng are similar to those for other cool-season crops, around 68-73°F (20-23°C). Growing mediums for ginseng must be free draining, but at the same time not impede the development of the forked roots — coconut fiber, or mixtures of fiber and perlite under drip irrigation are suitable. Overly wet substrate conditions should be avoided as these attract fungus gnats, the larvae of which can damage the roots and introduce infection. Some research has also indicated that for high-quality root production, ginseng can be grown aeroponically without the requirement for any growing medium. Spraying roots for 30 seconds every 10 minutes in the light period, and for 30 seconds every 30 minutes during the dark, has been stated as a suitable frequency. Ginseng can be prone to root rot and physiological disorders, so the use of disease-free root stock is recommended along with high quality water sources and solution disinfection. There is little information on suitable nutrient ratios or elemental levels for hydroponic ginseng, however, a low EC of 0.5-1.1 has been suggested for solution culture system. A high concentration of potassium has also been stated to result in an increase in ginseng root growth. Harvesting ginseng roots at the end of the growth period occurs when they have reached a fresh weight of around an ounce. Harvesting needs to be carefully carried out as damaged roots receive lower prices than intact ones. After harvest, substrate grown roots need to be washed then dried in drying rooms with forced air to ensure mold growth does not occur. Once dried, roots can be packed and stored until sold. Profitable hydroponic crops for indoor growers are worth a little investigation into market prices and cultivation techniques, taking into account yields, growing space, and time to maturity. However, many opportunities and a diverse range of crops exist within niche markets, even if some trial and error may be needed to perfect a new commercial enterprise. Maximum Yield 43