Buying Supplies for Ecocolumns

Students thoroughly enjoy building ecocolumns.  The supplies here are for 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.

Ecocolumns don’t need to be expensive. Read this article about cheap ecocolumns and more expensive equipment when you have some funds. Also read about where to find extra funds.


I begin Ecocolumns the 3rd week of school in the fall.  To prepare, I ask students to bring in 1 gallon “Crystal Geyser” water bottles. They can be empty or full.  I like the water bottles, because they are sturdier than 2-liter soda bottles, don’t tip over as easily, and many families don’t drink soda anymore. (But, many teachers still use soda bottles just fine) Students can donate the purified water in buckets which can be used later on in lab.  You can also ask teachers to donate bottles as many teachers at my school bring water for their own use in their classrooms.

Students need 3 bottles to build, but I always have them bring 4, because many need a spare for a mistake cutting the bottles.

This is the exact style of water bottle needed. Similar shapes (Kirkland from Costco) don’t work as well as this shape for ecocolumns.

Buying Supplies

I’m not very strong and can hurt my back easily, so I drag my teenage sons with me to buy supplies.  Since I teach 5 sections of APES with 9 groups of students per class, that’s 45 ecocolumns to buy for.

Get construction gravel as its cheap. Students can clean the gravel with colanders. I buy 3 bags for 45 ecocolumns.
Play sand is usually the cleanest sand. Teenage sons are very helpful. I buy 3-4 bags for 45 ecocolumns
After years of buying cheaper soil, I now buy Miracle Grow as it has the least amount of silt (which can dirty aquatic chamber water). Its worth the extra price. I buy 2 large bags for 45 ecocolumns.
Fortunately, I have a donation account which covers expenses. 
400 pounds of material ready for building ecocolumns
Seed packages. Look for seeds that germinate quickly as students hate to wait 10 or more days for plants to grow. Herbs are a good choice as they smell good and kids can eat them.

Students must also choose a legume for nitrogen fixation (a valuable part of the learning objectives in ecocolumns)

Other Supplies that I Already Have

I have a colander for each group. They use to clean the gravel. I bought them at the dollar store.
Students need scissors, a sharpie to draw lines for cutting and labeling, a box cutter to make initial punctures in plastic, a tea candle and dissection probes for burning holes in lids. Some don’t let students handle the box cutters and instead go around to each table to make the punctures. I’ve never had any problems with students hurting themselves or stealing the cutters. Some teachers also use a different method for drainage holes that don’t require probes and candles.
Plant lights if you don’t have a good window. I have several sets of plant lights purchased with grants. You can also build lights yourself inexpensively. Many teachers use windows and they also work well for ecocolumns
Fish for aquatic chambers. Gambusia (mosquito fish) are my favorite and I keep them year-round in several aquariums, but minnows and guppies also work well. You can purchase Gambusia from Carolina Biological or ask your local health department vector control for some. You won’t need fish for the initial 2 weeks. Gambusia are great in cold and dirty ecocolumn aquatic chambers
Freshwater plant such as elodea (Anachris at the pet store) or duckweed. You will not need for the initial 2 weeks.
Probes for water quality testing. DONT PANIC if you don’t have any as they’re expensive. I’ve built up my supply over many years writing grants. Instead, use regular thermometers, buy cheap pH probes or use pH paper, and buy a water testing kit if you don’t have many students.  If you have any funds, splurge or a dissolved oxygen probe to rotate.  My students rotate and share probes as they only need a probe for a minute or two to get a reading.
I use nitrate test strips as I don’t like nitrate probes. I buy several bottles each year for ecocolumns.

Next is Cutting and Filling Ecocolumns

Group Data Analysis

At the end of Ecocolumns, my students graph their data and answer questions as a group. Here is an example of the questions they answer.  This year, my students filmed their answers on Flipgrid.  For props, they used their ecocolumns, graphs and an optional small white board.

Soil and Water measurements

Choose 2 of the following questions to discuss and answer with your group. One person from your group will record your discussion on the answer sheet.

  1. Look at your plant height graphs (including elodea). Discuss what happened with your various plants over time and the possible reasons for the changes.
  2. Look at your water pH graph. Discuss what happened with pH over time and the possible reasons for the changes or lack of changes.
  3. Look at your water dissolved oxygen graph. Discuss what happened with DO over time and the possible reasons for the changes.
  4. Look at your water Nitrite/Nitrate graph. Discuss what happened with these measurements over time and the possible reasons for the changes.
  5. Look at your soil measurements: Temperature, pH, fertility.  Discuss what happened with these measurements over time and the possible reasons for the changes.

Adjustments, Observations, Error and Design

Choose 2 of the following to discuss and answer with your group. A different person from your group will record your discussion on the answer sheet.

  1. Discuss 2-3 adjustments. How did they improve your ecocolumn?
  2. Discuss your observations. What were the most significant observations? Why?
  3. Discuss mistakes and errors that were made during the ecocolumn lab and how they influenced the lab.
  4. Discuss how each of the chambers in the ecocolumn affected the other chambers.

Science Practice: Asking Questions

Science is all about asking questions. In fact, there is an important article in The Journal of Cell Science entitled “The Importance of Stupidity in Scientific Research” by Martin A. Schwartz in which he outlines how real scientists don’t know the answers to many questions, but they ask a lot of questions in order to consider pursuing a line of research.

Write down 5 questions about your ecocolumn that you don’t have the answers to, but that interest you.


Ecocolumn Articles

Student directions for building ecocolumns.

To read about building ecocolumns, go to these posts: Cutting and filling bottlesplanting seeds and taking data , adding bugs, worms and leaf litter, and building the aquatic chamber.

Read about where to find funding for supplies.