2017 ASHS Annual Conference

Micro-hydroponics involves growing miniature (less than 30.5 cm tall) vegetables. A non-circulating hydroponic system using a 3.8-L plastic jug was found to be too tall for use on shelving under artificial lighting. The jugs also needed to be covered with aluminum foil to reduce algae growth. The objective was to describe a non-circulating hydroponic system for growing miniature vegetables. Oasis® cubes (3.2 cm x 2.5 cm) were placed in plastic trays (21.7 cm x 14.3 cm) and moistened with tap water. Two seeds (lettuce, tomato, chili pepper, or watercress) were placed in each hole of a cube, and clear plastic lids were placed on the trays. Trays were placed under artificial lighting, and additional water was added as needed. The hydroponic nutrient solution consisted of Hydro-Gardens Hobby Formula 10N-8P-22K fertilizer (5.0 ml per 3.8 L of water) and magnesium sulfate (1.3 ml per 3.8 L of water). When seedlings were 2.5-5.1 cm tall, the cubes were placed into 5.1-cm diameter plastic net pots. Milk or juice cartons (3.8 L) with a screw cap spout were used as containers with a 5.1-cm diameter hole cut out from one side of the carton. Cartons were filled with nutrient solution, making sure it touched the bottom of the cube in the net pot. As the vegetables grew, additional nutrient solution was added so that the cartons remained 1/4 full. When the seedlings were 2.5-5.1 cm tall or started to touch the clear lid, the lid was removed. Cartons blocked sufficient light so that algae growth was minimal. The cartons were not made for long-term use, thus the material around the 5.1-cm hole wore out, and the weight of the plant caused the net pot and plant to fall into the carton. Screw cap spouts made it convenient to add additional nutrient solution, especially when plants grew large and covered the hole in the carton. Cartons were good for one-time use as they started to soften and algae grew inside the carton. The non-circulating micro-hydroponic system is a simple hydroponic system for growing miniature vegetables. Its advantages are the use of recyclable material and its low profile for growing under artificial lighting on shelving. I thank Bernie Kratky and Jensen Uyeda for their assistance.