A "sweat box" style germination chamber built using readily available parts and a broken chest freezer that provides humidity and temperature control. Early season germination can be inconsistent without a closely controlled environment for starting seeds. Commercial greenhouses use similar systems but the cost can be prohibitive for the small vegetable grower. This is a branch of the first version posted to Farm Hack (http://farmhack.org/tools/sweat-box-germination-chamber)
I built (or modified) this tool
No votes have been submitted yet.

Sweat Box Germination Chamber V2 with temperature and humidity control (reference to Farm Hack tool http://farmhack.org/tools/sweat-box-germination-chamber)

Sweat Box Germination Chamber

Problem Statement/functional need:

Commercial growing operations often use high-cost germination chambers to start their seeds. For the small farm, a low-cost, DIY version which can be put together using readily available materials is needed. This design simplifies construction by eliminating the auto water fill and using off the shelf slow cookers, and enables independent setting of humidity and temperature, while also reducing cost.

This germination chamber can be put together for $100-200.

Functional Description/approach:

This build uses slow cookers for heat and humidity control that are wired into temperature and humidity controls that are mounted into the freezer door. The humidity control is connected to a slow cooker with water at the base of the freezer initially but then replaced with a drug store humidifier to enable adding humidity without increasing heat. The temperature control is connected to a slow cooker in the base of the freezer filled with vegetable oil. The chamber reaches and holds the target humidity within a few percentage points( tested at set ranges from 70%-90%) within a few minutes, and the temperature reaches and holds to within a degree in a couple hours (tested and set ranges from 75-85% with outside temp at about 40%).

Wiring:

Power cord is fed through a metal wire clamp on the hing side of the door.

Metal racking is same as tool http://farmhack.org/tools/sweat-box-germination-chamber

 

How to use the tool:

Set temperature and humidity at the door. Check water and oil levels periodically (but neither seems to be budging much) and watch for germination!

http://imgur.com/a/lTcyX

 

  • Set temperature and humidity at the door
  • Monitor water level in slow cooker.
  • Watch for germination
  • Otherwise, that is it! 

Comments

Tool comment

Does it matter what kind of slow cookers you use? I.e. just one with a manual switch that has "Hi, Lo, Off"? We're going to be starting our build this weekend and I want to have the right kind of slow cooker. I'm a rookie at this stuff so please forgive if this is an obvious question. Do you have more detailed pictures of the way you connected the heat and humidity controls to the crock pots?

 

Thanks!