Maximum Yield USA August 2017 | Page 80

trends & technology Hydroponic strawberries are a popular greenhouse and commercial crop. “ OR THOSE NEW TO BERRY PRODUCTION, STRAWBERRIES ARE THE IDEAL CROP WITH WHICH TO GAIN SOME EXPERIENCE.” 78 grow cycle Hydroponic growers can buy chilled runners or plugs (called “frigo” or “pre- conditioned” plants), which have had a period of four to eight weeks under refrigeration (34-37°F). Or, growers may chill their own stock by wrapping the clean runners or small plants in damp paper and plastic, and placing them in a refrigerator for four to six weeks. Either way, the artificial chilling repli- cates the cold conditions of winter, which is especially great for those in tropical locations or where winters are very mild. Once planted out into the warmth and light, the plants resume their spring growth pattern of foliage development. They flower relatively quickly, followed by fruiting. While pre-conditioned runners or plugs are available almost year-round in some regions, this type of plant- ing stock is raised pretty much exclu- sively for outdoor gardeners and thus is often only available in spring. Indoor growers therefore may need to consider raising their own planting stock if they want to produce berries out of season. Strawberry plants are relatively easy to propagate from runners produced at the end of the fruiting season, and there has been a recent development of large fruited types that can be raised from seed. Hydroponic systems for strawberry production are diverse. With a suitable, high intensity lighting set-up, straw- berries can be grown in vertical stacks or towers, which make an impressive display when in fruit. However, care needs to be taken on the lower levels of vertical systems, where light and air flow are often restricted, resulting in lower yields and increased occurrence of fungal pathogens. The strawberry plant is particularly sensitive to moisture and crown/root rot is the number one cause of strawberry plant deaths. Beginners are advised to try their first strawberry crop in a free- draining, media-based system, such as perlite or a 50/50 coconut fiber/perlite combination. Even rockwool cubes can work, provided they are well-drained. This way, the plant can be easily posi- tioned with the crown just above the surface of the media. Drip irrigation systems are preferred, as ebb and flow can cause salt buildup around the crown, which also leads to problems. Strawberries can be grown well in nutrient film technique (NFT), aero- ponics, and various modifications on these systems, but plants need to be well supported so they don’t slip down into the nutrient flow. Only clean plants—i.e. not those coming