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A homemade Germination Chamber

Written by Søren Larsen.


Jim Bruce write:

-- Most seed species prefer a diurnal temperature variation when actual germination proceeds, and Vitis is no different.  We found that a 20/30C (68/86F) diurnal variation was optimum for Vitis germination under our laboratory conditions for speedy germination and high percentage of germination.  Although, Vitis will germinate at 15/25C, it is much slower and often doesn't obtain the highest germination percentage.-- 

Well, I normally got very low germinations % so this must be a great help, I hope. Now a professional climate chamber is expensive, so I have made this little device:


Plastic chamber / box is 18,5 Gallon. Price 8 $


View of the "heating source" ; a 100W electrical bulb, a fan is added to ensure same temperature all over inside the box.


The 100W bulb can raise the temperature app. 12 C in the box, depending on isolation and box material. I have added a metal reflector between the bulb and the box in case there should be a fan failure. I have tried the box without running the fan, and the plastic is around 40 C worst case. But I like to be on the safe side ...

The fan is from an old Computer supply. Supply Voltage is only app. 7 V, this means that the RPM is low and less noisy.



Temperature controller is from an old farmers barn, and the alternating temperature is made by a mechanical clock switch.


Jim recommend a temperature cycle of 8h / 16h. Now set the clock-switch to turn on heat 16 hours during the daytime.(Maybe you get some help from the sun) During night the temperature will lower to room-temperature, and this is typical 20 C here. We see how the temperature cycle will be ...

Temperature log of the box over 3 days. .


Phil Napoli have made a similar design, using water Click here.