Marsh Botanical Gardens

1. Marsh Botanical Gardens Introduction to the Research Plant Growth Facilities

2. Plant research growth facilities Greenhouses Growth chambers

3. Overview As Plant Research Facilities Manager, I oversee about 10,000 square feet of research greenhouses and plant growth chambers at Marsh Botanical Garden and Science Hill. This project proposal is centered at the growth chambers at Science Hill. These 12 environmentally-controlled walk-in chambers are used by researchers from six plant science labs in the department of Molecular, Cellular and Developmental Biology.

4. About the size of a restaurant walk-in refrigerator, each chamber has from 16 to 24 shelves with individual grow lights and a common heating, cooling and humidification system. The climate can be tightly controlled to create artificial days and nights within specific temperature and relative humidity ranges for customized plant growth programs.

5. These specialized climate-controlled spaces are used to grow model organisms for plant biology and genetics research. Most chambers are used for growing Arabidopsis thaliana, a small mustard family plant and model organism; Nicotianabenthamiana, a tobacco plant relative and model organism; Zea mays, or corn, also a model organism; and assorted other plants, including citrus, tomatoes, and potatoes.

6. The challenge: irrigation

7. While the growth chambers offer the advantage of fine climate controls, there is one trade-off: ease of watering. Plants can’t be top-watered because excess irrigation would ruin the lights on the shelves below. So, all plants are placed inside containers and sub-irrigated, or bottom-watered.

8. Problems arise when researchers leave their plants in standing water, which leads to oversaturation, or over-watering. Plants become stressed and unhealthy because they’re not allowed to “breath.” Oversaturated soil develops algae, which in turn attracts damaging plant pests and pathogens that thrive in these environmental conditions.

9. The proposal: self-draining trays

10. My engineering challenge: to devise a watering system that allows for draining of individual trays after about ten minutes, at which point a pot will suck up all the water it can use. Given that there’s 64-96 trays in each chamber, that can be a whole lot of drainage tubing. There’s only one floor drain in each walk-in. There are systems available, including ebb-and-flow shelves, but the cost is high and exceeds our budget. I’m hoping to find a low-cost materials alternative that accomplishes the same goal.