BABY LEAF LETTUCE

1. Medium Filling

The production of lettuces and herbs starts with substrate or medium filling. Unique patented open gutters are automatically filled with a continuous strip of growing substrate. Typically, our systems use peat or rockwool as a growing substrate. We are continuously researching alternative substrates which offer advantages to the grower.  There are several system versions available depending on the use of a solid growing medium such as rockwool or a loose growing medium such as peat.

2. Sowing

After medium filling, the sowing machine seeds directly into the gutters. The plants will stay in the same growing gutter throughout the entire growing process—transplanting is not needed. A typical sowing line consists of multiple drum seeders which are usually optimized for the use of pelletized seeds as well as band seeders for raw seed. These drum seeders are designed for the unique application in conjunction with our gutters, allowing for precise placement inside the gutter. The continuous strip of growing medium allows for customized spacing of the seeds per gutter, specific spacing for each variety or even for each growing line.

Gutter Management

Once sowing is complete, the gutter is transported into the greenhouse and placed on the germination area of the growing system. For this, a variety of tools such as conveyor belts, pushers, elevators and turntables are typically used.

3. Germination

During the initial phase of the growing system, the gutters will be moved through the germination area. In order to maximize the growing space, we have developed a lower level for the germination phase, located beneath the main growing line. After germination, an automatic elevator lift moves each gutter from the lower level and places it on the upper growing line. Depending on the greenhouse layout and system specifications, the germination area might be at the same level as the main growing line. In any case, the germination area typically is enclosed and has the ability to control temperature and humidity.

4. Growing

Our growing gutters with continuous growing medium enable free positioning of seeds in gutters. The distance between plants can therefore be precisely optimized to your specific growing needs and ensures effective use of the greenhouse. As the plants grow, the gutters move automatically through the greenhouse toward the harvesting area. During that process, the distance between the gutters is adjusted according to the space requirements of the plants in each growing phase. The automatic adjustment and movement of the gutters give the plants as much space as necessary, but as little as possible, thus ensuring maximal usage of the greenhouse. The plant density achieved with the adjusting gutters is unmatched and a key component in efficient growing.

Gutter Management

Gutters with the harvest-ready plants are automatically moved from the growing area (“under glass”) to the processing area. Depending on system layout, a variety of tools such as conveyor belts, pushers and turntables are typically used.

5. Harvesting

At the harvesting station, the gutter will be guided into the fully automated harvesting/cutting station, which features rotating cutting blades, a variable frequency controlled blower motor function which blows the leaves up, as well as the ability to adjust cutting height and various speeds. A large number of parameters can be selected by the operator to achieve optimum cutting yields. The harvested gutter is sent forward to the removal station (Step 6) and the cut baby leaf lettuce is transferred further for optional mixing and packaging. All this can be done in a fully automated process without any need for manual labor.

6. Removal and Cleaning

After harvesting, used growing substrate and plant roots are removed from gutters. Automated waste management is available (Waste removal—additional process steps). Next, the gutter is washed and typically disinfected with only hot water by the automatic gutter washer. The clean gutter is then automatically moved to the buffer.

7. Buffer

The gutter buffer between the last step of a gutter rotation and the beginning of the next cycle assures operational flexibility by allowing seeding and harvesting operations to operate independently of each other to a certain degree. From the buffer, the gutters are pushed to the substrate filling area and will be reused as the growing cycle begins again.

Additional Process Steps

Mixing of Lettuce

The system can be equipped with an integrated crop mixing system physically located after the cutting machine. The mixing station can handle several different mixing configurations and gently mixes the plant varieties according to the pre-programmed mixing settings.  The system harvests plants in a pre-programmed pattern, ensuring that just the right number of gutters are harvested for your mix and that no lines are under- or over-harvested. The mixing configurations can easily be set up and changed during daily operations, making it possible to offer a wide portfolio of different blends. The mixing station is equipped with conveyors for moving the harvested crop to the packing area.

Supply of Growing Medium

For a rockwool system the supply of growing medium is achieved by periodically loading pre-cut slabs into the medium filling machine. In the case of loose medium, the system features a bale breaker which is re-filled with large bales.

Waste Stream of Substrate

The standard system is equipped with a single conveyor which takes the waste substrate stream from the removal machine to a mobile dumpster. Alternative solutions are available.

Irrigation and Fertigation System

Plants are irrigated and fertigated automatically by our control system. In the irrigation system the water is dosed to the gutters from drip emitters. Excess water flows from the gutters to the return water tanks, which can efficiently be placed under the growing lines. By using this smart irrigation system, we make certain that plants get the correct amount of both water and nutrients. Water that is not consumed by plants is cleaned, returned to water tanks and then reused for irrigation. A powerful and robust filtration system ensures highest water quality for your leafy greens. Using a hydroponic NFT system and re-circulating the unused irrigation water reduces water consumption by up to 95% compared to open-field farming.