GreenHab Report
Mark Gee
03Jan2018
Environmental control: Heating, Cooling with fan and vent, open door.
Measurement Hour: 06:20 PM
Inside temp at measurement hour: 16 C
Outside temp during measurement hour: -2 C
Inside temperature high: 32 C
Inside temperature low: 14 C
Inside humidity: 21 %RH
Inside humidity high: 30 %RH
Inside humidity low: 16 %RH
Hours of supplemental light:
For the crops 05:00 to 11:59 PM
Changes to crops: Heat stress in several plants due to temperature extremes. Extra water was given to these plants. A small moth was flying in the habitat.
Daily water usage for crops: 7 gallons
Time(s) of watering for crops: 10:30AM, 06:30PM
Research observations: The microgreen seeds have been covered with plastic wrap and well watered to keep the moisture in. They are beginning to germinate and some have opened their cotyledons. No greening is observed. Brown stains, possibly algea, are forming on the capillary mats of the soil-free trials. Temperature extremes were recorded and may have a negative impact on plant growth.
Moringa seeds have not sprouted. The tomatoes watered with moringa extract are growing well.
Changes to research plants: None.
Aquaponics: Not set up.
Narrative: The sun was shining bright and cheerful all day long. You might think this would be a good thing for plants growing in a greenhouse, but you would be wrong. After helping send off the EVA crew in the morning, I walked to the Green Hab and found several cucumber, tomato, and bean plants wilting. The strong sunlight caused the environment to heat to 32C (90F) which is a stressful temperature for potted plants with limited water. I immediately watered the plants that needed moisture and tried to find a way to release some heat. The outside temperature was near freezing, but opening the door did not release enough heat to keep up with the greenhouse effect. I turned on the fan to the maximum setting, but the cold air blew in so quickly that the plants near the fan reacted poorly. At the lowest setting, the air circulation was not enough to cool the far end of the habitat. I spent some hours adjusting the fan, door, and vent while moving the thermometer around the greenhouse to try and find a way to keep the whole habitat at a reasonable temperature. This was even more challenging because only one half of the building is covered by a shade cloth. Covering or uncovering the entire habitat would make thermal control much easier. What seemed to work best for now was setting the fan on low, opening the vent on the far end of the greenhouse, and keeping the door closed. This kept the temperature near 25 C throughout the habitat. Adjustments will be needed as the outside temperatures change. The increased air circulation means the crops will use more water, but thirsty crops are better than no crops.
Support/supplies needed: Shade cloth for the second half of the Green Hab. Do we need to do something for insect control? What is the threshold for action?