Germination chambers provide optimum conditions to aid the growth of seedlings from seeds or sporelings from spores. They consist of a temperature- and humidity-controlled space to provide the best environment. The chambers are set up inside a greenhouse or as freestanding units.

Although the conventional process of a layer of plastic around the seeds is effective, it offers inferior thermal insulation efficiency compared to germination chambers. Using chambers facilitates uniform germination within a shorter period.

The majority of commercial crops sprout from seeds. The initial growth stage of seedlings requires particular heat and humidity conditions to maximize germination counts. The chambers contain densely packed rows of soil in flats. Uniform and efficient distribution of heat is critical for successful germination of the seeded flats.

Germination chambers are custom designed for specific applications to offer flexible lighting conditions. They are purchased or self-assembled at a lower cost, provided one has the necessary expertise. Germination chambers range widely in size - from closet-sized compartments to small warehouses. They provide ample insulation for retaining heat, maintaining its uniform distribution, and keeping the temperature and humidity at an optimal level. 

Operation

Germination chambers maintain temperature and humidity levels to create a favorable growth environment. They are used only in the initial growth phase and have the capacity to hold hundreds or thousands of seedlings. A heating unit with a separate water supply, fitted at the base of the chamber, allows heat to radiate upwards. The unit helps control the inside temperature and acts as a humidifier.

Flats containing seeded soil blocks are laid out horizontally along the chamber or stacked in racks. In several germination chambers, insulation material sits under the chambers and allows the light to enter from the top and the sides. They may also feature a removable or hinged roof to allow access for watering. Small, low-speed fans ensure heat circulation throughout the chamber.

Compared to large greenhouses, germination chambers provide a better environment for seed growth due to their smaller size. A compact, well-insulated space provides more control over temperature and humidity fluctuations. Germination chambers consume less water during irrigation and use less heat, leading to higher efficiency.

Extreme levels of humidity inside a germination chamber lead to certain challenges. Chambers lack the natural ventilation of a greenhouse or outdoor sprouting area. This can cause fungal and bacterial contamination. Systems that introduce water into the chambers naturally have advantages over systems that require hand watering. They generate and maintain ideal humidity conditions inside the chamber and keep water off the soil surface.

Features

Germination chambers offer a wide range of features, depending on their make and purpose. Simple homemade chambers offer a lid for hand watering while more advanced chambers have automated controls for regulating temperature and humidity. Some of these features include:

• Door gutters (collect condensation and send it back into the chamber)
• Ventilation fans
• Water level switch
• Piano hinge doors (allow full opening of doors)
• Clear polycarbonate doors
• Rotating adjustable circular vents
• Screened ventilation openings
• Water reservoir with automatic water level control
• Thermostatically-controlled heating element (submerged in water for delivery of moist heat)
• Aluminum heat baffle (offers additional heating)
• Water level sensors (turn off heating element if needed to avoid damage)
• GFCI cord end
• Digital temperature display
• Thermostat controls for heating and ventilation fans
• Shelf brackets
• Metal-edged plastic shelves
• Rolling casters (for easy movement)
• Slide-out shelves
• Magnetic door gaskets (provide a tight seal)
• Horizontal air flow
• Continuously-running condensing units
• Remote control capability (allows programming of chamber conditions such as temperature, humidity and lighting from devices such as laptops or smartphones)

Selection

Germination chambers are self-assembled, made-to-order, or purchased off-the-shelf. Users willing to hand water and manually adjust the position of flats may forego features such automatic humidifying or temperature control. Excessive moisture can lead to microbial contamination, so system humidity control is an important consideration.

References

Image credits:

CARON Products & Services, Inc. | Percival Scientific, Inc.