Prepared by Amy Storey Bright Agrotech, LLC Why Hydroponics? Prepared by Amy Storey Bright Agrotech, LLC

Population Growth The world population is growing fast! Experts predict that by 2024, the world population will reach 8 billion people. By 2040, the population will reach 9 billion! Critical thinking: What other problems could arise from a growing population? Mathematics: What is a linear line? Does population growth happen linearly? WorldOmeters: http://www.worldometers.info/world-population/

Space Needs How are we going to increase agricultural output to feed all these people? We don’t have enough space to feed 8 billion people using current growing techniques. More space does not mean more surface area or land. Creative growers use vertical farming to grow crops on several levels. Mathematics: What is the difference between square feet and cubic feet? Critical Thinking: In what other ways could we utilize air space in the future? (What kind of technology could be moved from the ground to the air?) What kind of problems do you think people will encounter when developing these new technologies for the air?

© Blue Legacy/Lauren McLaughlin, Flickr.com Water Needs Water usage is also a top concern as population increases. Droughts and water rights issues can make it difficult for farmers to get water. Current irrigation techniques are highly wasteful. Flood irrigation loses up to 50% of its water! © Blue Legacy/Lauren McLaughlin, Flickr.com Math/Chemistry: What is a limiting factor? Critical thinking: Do you think that space or water is the top limiting factor for farmers? How could you decide which one was more limiting by using information on plant needs? More Resources: http://brightagrotech.com/water-use-efficiency-hydroponics-aquaponics/

“Chinampas,” Wikipedia.org What is the solution? People have been experimenting with alternative growing techniques. The Aztecs grew crops using chinampas, or floating gardens on lake Texcoco. Nutrient-rich mud from the bottom of the lake fertilized the plants. “Chinampas,” Wikipedia.org Critical Thinking/Biology: Why do you think that the mud at the bottom of lakes, rivers, and ponds, has so many nutrients? Do you think that plants use fish waste directly, or is it processed in some way before the plants can use it? What organisms process nutrients? (Intro. to nitrification and nitrifying bacteria) More Resources: http://edenaquaponics.com/2010/04/a-brief-history-of-aquaponics/ The Chinese also harvested nutrients from water organisms in their flooded rice paddies.

What is Hydroponics? The modern art of hydroponics was born in Australia. Hydroponics is simply growing crops without using soil. There are three types of hydroponics systems.

What is Hydroponics? A raft system grows plants in some sort of raft with holes in it. Roots hang into the water, where they take up nutrients present in the water or solution. “Hydroponic Swiss chard works really well in a floating raft. Bumper crop at Papa Farmyard” by Gabriella Yazickr, Flickr.com

“Sprout!” by Jesse Gerard, Flickr.com What is Hydroponics? A grow bed system uses a shallow bin (“grow bed”) filled with a media other than soil. This media might be clay pellets, crushed rock, or expanded shale. Water is constantly run through the media by a pump. “Sprout!” by Jesse Gerard, Flickr.com

What is Hydroponics? Vertical hydroponics is a more complicated design, but it allows farmers to grow in a previously unused space. Vertical growing can save both water and space. Vertical aquaponic grow towers at Bright Agrotech’s farm in Laramie, WY.

Vertical Growing Challenges Light extinction When incoming light is used by plants at the top of a vertical system, bottom crops don’t get enough light to grow.

Vertical Growing Challenges Difficult Maintenance Systems with large components can get bulky and heavy. Harvesting can be difficult and time-consuming. Difficult maintenance usually means high labor costs.

Vertical Growing Challenges Costs can be higher than revenue A grower has to think about many costs when building his system: labor, equipment, installation, water, electricity, rent, inputs… The system must work efficiently enough to minimize these costs. Chemistry: What is the difference between a liquid and a solution? Why is the water in hydroponics called a solution? Geology/Chemistry: What is shale? How do you think it gets expanded? Are there other rocks that can be expanded, and what are they used for? Critical Thinking: Why is it important that the water is recirculated? What is the other option beside recirculating water? Business: Why are labor costs important? How could you reduce labor costs for a raft or grow bed system? Categorize the costs listed into initial (or one-time) costs and periodical costs. (Weekly, monthly, or yearly bills.) How can you estimate whether or not revenue will outweigh these costs? Critical thinking: How could you reduce any of these costs using smart system design?

Problem Solving After looking at all the challenges of vertical hydroponics, it's time to think critically about system design. We need a system that allows light to get to the bottom crops is light and easy to move around, and has low costs. Do you have any ideas?