Greenhab Report – January 9th

GreenHab Report
Mark Gee

Environmental control:
Shade cloth on

Working Hour: 06:15PM
Inside temp at working hour: 18 C
Outside temp during working hours: UNK
Inside temperature high: 24 C
Inside temperature low: 16 C
Inside humidity: 40 %RH
Inside humidity high: 48 %RH
Inside humidity low: 28 %RH

Hours of supplemental light:
For the crops 05:00 to 11:59 PM

Changes to crops: Quinoa seeds did not germinate and rotted in the tray. Threw them away. The past days have been very cold and cloudy. Nothing has germinated yet.

Daily water usage for crops: 6.5 gallons

Time(s) of watering for crops: 10:00AM, 06:15PM

Research observations: Microgreens seem to be growing much better in the shady environment. Maybe the full sunlight was scorching them.

Changes to research plants: Applied fertilizer to microgreens.

Aquaponics: Not in use.

Narrative: Watering needs to be as efficient as possible in a Martian habitat. But after I finish watering, I often look around and see a water on the floor.
Some of the water comes directly from accidental spilling becase the spout of the watering can holds water and drips when turned upright. This waste could be eliminated with a differently designed spout or by using something crazy like a giant syringe so that no water is relesed unintentionally.

Most of the leakage comes from water that is poured into the pot and flows quickly through macropores in the soil and out the pot before there is time to soak in. This is a tricky problem to solve. The macropores are a beneficial part of soil structure and should not be removed by compacting the soil. If I water less so that less water flows through the pores, the plants might not get enough water.

We are currently trying to reduce this waste by growing plants on vertical shelving so that the plants below can catch the water leaked by the plants above. But this is not a perfect system. Another option is to install trays beneath every plant so that the leakage can be captured and recycled. It is uncertain how much labor this method would require and how much of the water would evaporate before it could be reused. A third way to reduce this waste would be to use drip irrigation tape that continually releases water into the soil at a slow rate. This would increase water use efficiency and also reduce the labor requirements for the astronauts. However, an adjustable drip tape would have to be invented so the same tape could be used with different crops. And it may not be feasible to rocket yards and yards of drip tape to Mars.

For now, I will stick with my watering can.

Support/supplies needed: None

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