Last night I enjoyed a delicious and abundant plate of fresh mixed greens, dressed in olive oil, and accompanied with freshly baked bread - one of my favorite dishes. All summer long we have had loads of fresh fruits and vegetables brought to us on a regular schedule by airplanes, but since station closing three weeks ago, with no more flights coming our way for the next eight months, we are eating produce from our own hydroponic greenhouse: a marvel of technology that allows us to grow fresh vegetables in a location where there is no soil, no sunlight for 6 months, and where the temperature never rises above freezing.
My dinner salad on March 9 at the South Pole!
The Antarctic Treaty prohibits us from bringing soil to the Continent, so the National Science Foundation turned its attention to the University of Arizona: the same institution that is developing greenhouses for a possible human settlement on the moon. With no settlement on the moon, yet, the South Pole greenhouse is probably the most extreme environment where plants have been grown.
The hydroponic chamber is a closed and controlled environment where all the inputs (water, minerals, carbon dioxide, and light) are precisely administered to the plants; all the critical parameters (temperature, humidity, PH) are controlled, and all the outputs (liquid and gaseous efflluents, and weight and type of the produce) are accurately measured. Seeds are planted in a sponge-like material, germinated, pollinated, and transferred into larger trays where they can grow to their normal size.
The rate at which the plants grow is phenomenal. Intuitively I would have thought it difficult for plants to grow outside of their natural environment, but, as Lane, the researcher from the University of Arizona who visited us in the summer, explained to me, it is just the opposite. In the greenhouse we can give the plants exactly what they want: the right amount of light, the right temperature, the right amount of nutrients, the right air composition. In fact, we could make plants grow even better if we only could optimize the parameters for a single crop, but because we have a great variety of vegetables that we grow, we have to make compromises. For example, strawberries like 15 hrs of sunlight every day, but that would not be good for other plants, so our strawberries do not grow as fast and as large as they could. Another reason why plants grow so well here is because there are no bugs, no birds, or other extraneous living organisms trying to go at them. Therefore, we do not use any pesticides, which makes all of our vegetables organic. We do have to be careful about mold, which has developed occasionally. So a big part of the job of the greenhouse caretaker is to thoroughly clean the trays with bleach before planting a new crop, and constantly inspecting the roots of the plants. If there is mold, the plant must be removed, the mold must be observed under a microscope for identification, the information is shared with the experts at the University of Arizona, and an appropriate course of action is taken.
Although we are nowhere close to space, the cost of producing these vegetables is astronomical. We have estimates, which include the cost of melting ice to produce water, the cost of transporting fuel by airplane to produce electricity, the cost of transporting all the nutrients, including the cylinders of carbon dioxide, etc., and I do not even want to venture publishing that figure in a public blog. I just try to savor and appreciate my delicious fresh greens every day knowing how much study, research, and care has gone into bringing them to the table, and knowing that through all this work we are advancing science.
It doesn't take a Ph. D. to run the South Pole Greenhouse, but it doesn’t hurt. Susan, our greenhouse caretaker, holds one in Chemistry and has spent most of her life as an Analytical Chemist before coming to spend the winter with us at the South Pole. Besides her job in Colorado, she left her lovely dog George. The Antarctic Treaty prohibited George from following her this time. Susan’s dream job is to run an analytical chemistry lab on board a sailing ship on an around-the-world sampling cruise.
Plants grow in plastic trays. The root system develops in a sponge, which is fed with water and nutrients through a complex computer-controlled hydraulic system of pumps, mixers, tubes, valves, and measurement sensors, hidden under the plastic trays. The trays are built on rails and can be moved in and out to expose different plants to different amounts of light.
Green lettuce is my favorite vegetable. We harvest the larger leaves and let the plant continue to grow until the following harvest.
We also grow excellent red leaf lettuce.
Our basil does very well …
… as do our tomatoes. Too bad we have not yet figured out how to make fresh mozzarella, because I do miss Caprese salad every now and then.
This is Bok Choi, a green that I did not know about until I came here at the South Pole. It is of Asian origin, and grows very well in our greenhouse. It is also very good.
Beets and Swiss chard.
My favorite vegetable to eat steamed is kale. Luckily, we have lots of it here at the South Pole.
Besides vegetables, we also grow flowers, not for eating them, but for reminding us of the world we left behind. In addition to sunflowers, we also grow chamomile flowers, which we use to make soothing evening drinks as a fresh complement to the variety of teas that we already have on station.
On February 23 we had the first harvest party of this winter season. Here is Shannon holding a large bag of fresh lettuce, Rico, enjoying his work, and John and Joselyn hard at work in the back. On that day we harvested more than 100 lbs (more than 45 kg) of fresh vegetables. Working in the greenhouse brings back the memory of smells that we do not get to experience here at the South Pole. The humid air feels thick, when compared to the 3% of relative humidity in which we live inside the station (Photo courtesy SP).