CD Case Rhizotrons (Rhizoboxes)

We developed 3D printed components for this affordable, low-input method of growing plants for root visualization. Inspired by this awesome paper https://doi.org/10.1002/aps3.11340 

What is a rhizotron?

Originally they were a laboratory constructed underground in order to study soil and its interactions with plants and animals. Today in the plant sciences, the term has become more commonly used as a term for a device enabling the visualization of plant root growth without disturbing the natural habit of the organism. They are also sometimes referred to as rhizoboxes. More info from one of the largest manufacturers of them here.

Requirements:

• Access to a 3D printer with at least a 180mm build plate

• Filament (we recommend PETG, PLA lasted ~4 trials before beginning to break)

• CD cases (we purchased CD cases from ULine (~$70/200 cases) for our trials)

• Sand and your chosen soil mix

• Seeds

• Water

• (Optional but recommended) Hot Wire Foam Cutter to cut off the hinge part of the CD case (preferably a tabletop one like this); alternatively, you can use a razorblade to score the case then break off the pieces with pliers

What do you do with these?

• Grow plants so you can see how the roots grow

• Educate people about plants

• Science!

General recommendations from our experience:

• Soil mixes should be at least 50% sand and the rest your desired potting mix to make filling the CD cases easier (we tried pure sand, perlite, vermiculite, and potting soil for reference)

• Leave the soil mix dry for filling the CD cases (if it's wet there will be a lot of air pockets)

• Assemble the CD cases with the 3D printed snaps before filling with soil

• (For Low Profile Stands) Wrap the cases in the cheapest aluminum foil you can find for light exclusion rather than the plastic bag sleeves and duct tape used in the original paper (faster, easier to remove, and hold up well)

• Thicker or more expensive foil actually functions worse than the cheap thin stuff (the tolerances between the printed parts and the CD case are designed for thinner foil as well)

• Foil can be unfolded and reused ~5-7 times before needing to be replaced

• Water the CD cases using a very light stream of water or let them sit in water for a period of time rather than top watering

• We recommend either of these for top watering Vase Mode Can or Teardrop Watering Can)

• CD cases typically last ~5-10 uses before becoming broken beyond use

• We found no significant difference between growing angles but have included 0, 15, 30, and 45 degree stands in case other want to test it themselves