Recirculating hydroponics is a soilless farming method that utilizes a nutrient solution reservoir and a pump to continuously circulate nutrients through hydroponic growing tubes. As the solution moves through the system, it provides oxygen-rich nutrients, promoting faster and healthier plant growth.

The nutrient solution used in this recirculating hydroponic system is Hydro Green, a government-approved solution for safe hydroponic vegetable cultivation.

The Experimental Research Station in Dinh Hoa Nursery has successfully implemented and put into operation an outdoor recirculating hydroponic system without a greenhouse. This method offers numerous practical benefits, including simplicity, affordability, high productivity, and disease-free vegetables. Moreover, it can be adapted for small spaces, such as balconies, rooftops, and any well-lit area.

Step-by-Step Guide to Setting Up a Recirculating Hydroponic System

Step 1: Preparing Equipment

• Plastic cups or net pots: Use dark-colored or opaque cups to prevent light penetration, which enhances root growth and prevents algae growth inside the system. Drill holes around the cup for roots to access the nutrient solution. These cups/net pots, combined with a growing medium, support the plant’s stability.

• Seedling trays, plastic baskets, and growing medium: Suitable media include coconut coir, sterilized straw, biochar, and corn silk. Biochar, with its black color, is especially useful for blocking light and promoting root growth.

Step 2: Preparing Seedlings

Method 1: Direct Seeding in Net Pots

• Sow 1-2 seeds per net pot filled with coconut coir.

• Spray the nutrient solution lightly on the growing medium.

• Keep the seed trays in a cool, dry place, avoiding direct sunlight. (See Image 1)

Method 2: Seeding in Trays

• Use plastic trays lined with coconut coir and organic fertilizer.

• Place trays in a cool, shaded area, ensuring consistent moisture for seed germination.

• Once seedlings reach 2-3 cm in height, gradually expose them to sunlight for 3-5 days before transplanting them onto the hydroponic system. (See Image 2)