Automation for hydroponics

Departments - Hydroponic Production Primer

Incorporating automation can help hydroponic operations become more efficient and grow more productively.

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Fig. 1. Rafts for deep-flow technique (DFT) systems are quickly and effectively sanitized using this wash station.
Photo: Christopher J. Currey

One of the biggest costs for any hydroponic business, regardless of the crops they produce, is labor. Mechanizing processes to reduce the amount of labor required for crop production is a sure way one way to reduce input costs. While the primary reason for using mechanization and automating processes is to reduce labor costs, there are other benefits to automation. For example, in addition to saving on labor costs, it can also make more labor available for other jobs in the greenhouse, make certain tasks easier to execute and increase employee productivity. But benefits of automating extend beyond labor. Automation also reduces the time it takes to accomplish tasks and expedites processes and may open additional space in your facility and help you turn crops.

Regardless of what scale you are producing on, there are steps you can take to improve your efficiencies by integrating automation and mechanization to improve productivity. Plus, there are some relatively easy steps to take to start automating processes in your greenhouse. Investing in a seeder is going to be one of the first things any producer should do. A vacuum seeder is going to be one of the first and easiest ways to incorporate equipment to improve productivity. Manifold seeders seed one row of plugs at a time, whereas plate seeders will seed an entire flat at once; large facilities may benefit from using the larger drum or cylinder seeders.

Fig. 2. This leaf lettuce grown in nutrient-film technique (NFT) troughs is planted in one location in the greenhouse and, throughout production, the trough moves throughout the facility until it is fully grown, after which the trough moves down a conveyor to be harvested.
Photo: Christopher J. Currey

In the greenhouse, regardless of size, automation can be key to maintaining a productive growing environment. Nutrient solutions for recirculating systems require adjustment to keep the pH and electrical conductivity within target ranges. This can be achieved by hand, spot-checking nutrient solution EC and pH and making the adjustments as-needed. However, automated pH and EC measurement of nutrient solution properties and subsequent adjustments moderates root-zone conditions and minimizes unwanted fluctuations. Sanitizing the troughs for nutrient-film technique (NFT) systems and rafts for deep-flow technique (DFT) or raceway systems can also be a laborious process. The opportunity to sanitize NFT channels and DFT rafts keep your system clean and reduces disease incidences and increases food safety, but it can be a laborious task. Equipment simplifying routine sanitation reduces labor costs and helps maintain best management practices (Fig. 1).

The larger the scale an operation and production, the possibilities to automate become even greater; the return on investment increases with the scale of production. In order to centralize labor, from planting to harvest, in the same part of the facility, some production systems are designed to move crops through a growing environment throughout production. For instance, the lettuce grown in the NFT system in Fig. 2 is planted in the same area of the greenhouse where it is harvested. The NFT troughs move throughout the greenhouse and returns to be harvested. There are also opportunities to automate post-harvest processing and packaging. For common Dutch cucumbers produced hydroponically, conveyor belts facilitate transporting fruits from harvesting carts to shrink-wrapping machines, then onto cardboard containers for bulk packaging.

And there are some very exciting robots in the CEA industry. Grafted tomato plants are increasingly popular, but grafting is a very labor-intensive process. While these grafting robots still require labor to operate, they can complete up to 800 grafts per hour, greatly improving productivity. On the other end of production, we are not far from having automated harvesting as well! There are robots designed to selectively harvest hydroponically grown fruits such as cucumbers and strawberries.

Christopher (ccurrey@iastate.edu) is an assistant professor in the Department of Horticulture at Iowa State University.