Figure 5-1 

 The cocklebur greenhouse at Colorado State University. Note cooling 

 pads on the left, exhaust fan box on the right, lights hanging above the 

 benches, their time switches on the wall to the rear, thermoregulator 

 under a' shield protecting it from the direct rays of the sun (on a post 

 just right of center) plants trimmed and numbered for an expermient, 

 and the cart on the concrete walk-way to the left. Note also plastic pots 

 made by melting (with a hot soldering iron) two holes on opposite sides 

 of pint plastic ice cream containers, and painting them with asphalt 

 aluminum paint to reflect light and heat. Plastic is easy to handle, light, 

 and doesn't absorb chemicals. Larger pots produce slightly belter plants 

 but require more soil and are heavier. 



