We’re taught that fresh water is infinitely reusable, being replenished continuously by the earth’s water cycle. However, as California’s ongoing water crisis shows, rainwater doesn’t always supply the amount of water people need. The rest of that freshwater, in California’s case, is taken from aquifers that we are draining faster than they will be replenished. Drill sites are going deeper and deeper into California’s aquifers, sipping at a dwindling supply.
And you might be thinking, this is another reminder to turn off the sink when you’re brushing your teeth. But that amount of water is absolutely insignificant in comparison to the largest drain on the world’s freshwater supply.
Agriculture takes by far the largest share of the world’s accessible freshwater. Approximately 70% of the world’s freshwater goes to irrigation of crops. But does it actually go into growing the crops?
95% of water used for irrigation simply evaporates off the ground. The other 5% does useful work within the plant. We tested it ourselves by starting a grow cycle in the nanofarm with an incomplete plant pad.
The plant pad on the left has no cover, and therefore loses much of the water in the tray to evaporation. The plant pad on the right has its cover, limiting evaporation from the pad. The plant pad with no cover, which is similar to the uncovered soil on a regular farm, went through the entire tray (0.8 gal) of water in just 2 weeks, while the plant pad with the cover still had water (and a full crop of produce) after a month.
Many people ask us how the nanofarm can grow produce for over a month on just a small 0.8 gal tray of water when they are used to watering their potted plants every week or sometimes every day. The answer is that by controlling evaporation we make sure water gets used for what we intended - actually growing the plant. As a comparison, it takes 0.8 gal to grow a head of lettuce in the nanofarm, it takes around 15 gallons to grow a head of lettuce using drip-irrigation on a commercial farm. It takes far more than 15 gallons when using traditional irrigation techniques like sprinklers.
Israel is a country not new to the concept of water shortage. Israelis developed drip-irrigation in the 1950’s to save water, and now the irrigation method is used by farmers around the world. They are now pioneers in hydroponic technology that is growing more food with less water.
As freshwater becomes more scarce throughout the world, we’ll increasingly turn to solutions like hydroponic farming to be more efficient with our use of water.
The world will be just fine if we run out of oil. It will not be fine if we run out of fresh water.