Cutting and Filling Ecocolumns

Students thoroughly enjoy building ecocolumns. Building usually takes 2 full class periods (50-55 min). The example here is of an an ecocolumn with three chambers, a terrestrial chamber on the top with soil, plants and invertebrates, a filter chamber with sand and gravel, and an aquatic chamber with fish and water plants. For supplies needed, read the previous post.

Cutting the bottles

This is a “how-to” video explaining how to cut the bottles and create drainage holes in the lids.

I give my students a set of picture instructions. These instructions can be downloaded for free on Teachers Pay Teachers.

Cutting and filling usually takes the first day.

Bottles should be cut into these shapes. Maximize length on each bottle
Cut air holes in this bottle.
Use a tea light candle to heat up a dissection probe and burn holes in the caps
Its VERY important that one cap have 1mm holes and the other have 3 mm holes.
Measure the holes to make sure they are at 3 mm for the terrestrial chamber drainage. If they are not, it may clog.
Another option is for the teacher to us a bunsen burner to heat the probe and make one large hole for yarn. (Courtesy of Laura Solarez)
The yarn flows from the terrestrial chamber to the filter chamber with no knots (courtesy of Laura Solarez)
Burn holes in one of the cut off pieces to create a “sprinkler” to gently water seeds


Cutting bottles. Teach students to cut away from the body.
Trimming bottles using scissors so bottles nestle together well.
Burning holes in drainage caps
Measuring to make air flow “flaps” or “holes”

Filling the Bottles

This video shows you how to fill the ecocolumn chambers:

Below are some pictures of how to fill the chambers. Please DO NOT make an aquatic chamber at this time. Many dead fish have resulted from making the aquatic chamber too soon. You must wait 2 weeks.

Add gravel at the bottom of the terrestrial chamber and the filter chamber and then potting soil about halfway up the terrestrial chamber. Add 7-8 cm of sand on top of the gravel in the filter chamber. Let both chambers drain many many times. The sand will drain more slowly than the soil.
Filling a colander with gravel to take to the sink and wash thoroughly
Washing the gravel
Filling a chamber with gravel and then potting soil

At this point, students can clean up or if in a block period, they can go onto draining, planting seeds, setting up data, and taking soil data.