Classroom Data: Fall 2013

Collecting data at Cor Jesu Academy
Collecting data at Cor Jesu Academy

Goal: During our first semester in classrooms, we aimed to study how wild type green foxtail millet (A10.1) S. viridis would grow in classrooms. We wanted to determine the optimal environmental conditions for S. viridis growth as well as measure the length of the plants’ life cycle.

  • Over 260 plants were grown in six high schools in the St. Louis area. Schools ranged from public to private, from St. Louis City, St. Louis County and Wentzville.

 Environmental Data:

Environmental

Variable

Average

Standard Deviation

Room Temperature

22°C

1.5

Humidity

35%

0.03

Light Intensity

4515 lux

2450

  • Temperature: The average room temperature was 22°C, with little variation. This temperature appears to be sufficient for green foxtail millet growth.
  • Humidity: The average humidity in classrooms was 35%. Some classrooms experienced a change in humidity from the beginning of the semester to the end, and ranged from as low as 27% to as high as 45%.
  • Photoperiod: Millet plants did best when grown under a photoperiod of 16 hours of light per day.
    • Data collected by students at Parkway West High School shows that a shorter photoperiod will cause plants to be shorter, with small panicles.
  • Light Intensity: Different classrooms used different brands of light bulbs, which had a wide variation in light intensity (as measured in lux), which provided for some interesting growth patterns. The green foxtail millet grows best under high intensity lights, ideally greater than 8,000 lux.
    • Plants grown in the window with natural light (8,000 lux) at Vashon High School developed panicles earlier (42 days after planting) than plants under artificial lights (63 days after planting).
    • Two classrooms at Cor Jesu Academy used lights with very different intensities. The plants grown under lights with 8,863 lux developed panicles 18 days before the plants grown under lights with 2,796 lux.
    • Plants grown in a plant cart at Kirkwood High School under a light intensity of 1,717 lux did not survive to produce seed (watering may have also been a factor), whereas plants grown in more intense light in the same classroom did grow panicles.
  • Watering: Finding just the right balance of water was the greatest challenge to many classrooms. Over watering and drying out caused plant deaths in various classrooms. Most classrooms that had trouble with watering were over watering, so it is advised to not let the plants sit in standing water in the tray. Soil should be moist, not dry or soaked.

Life Cycle of Setaria in the Classroom:

Event

Average Days After Planting

Can See Green Plantlets Above Soil Line

10

First Seed Head (Panicle) Appears

58

Plants Mature & Begin Senesce

73

Collect Seeds

109

  • The date of panicle formation appears to be affected by light intensity. The plants grown under the most intense light (8,862 lux at Cor Jesu Academy) developed panicles after 42 days- over 2 weeks earlier than the average. Also, plants in the window at Vashon High School (8,000 lux) developed panicles at 42 days. I hypothesize that the more intense lights to be used in Spring 2014 will shorten the life cycle of Setaria viridis growing in the classroom.
  • Not all classrooms were able to collect seeds from mature S. viridis because they ran out of time. It does appear that if planted very early in the semester, S. viridis can complete its life cycle (15-16 weeks) in a semester when grown in a classroom. However, with more intense lights it is hoped that the life cycle can be shortened.
Measuring germination at Wentzville Holt High School
Measuring germination at Wentzville Holt High School

Where plant science research meets the classroom