Heating & Cooling & Movement Heat the air in winter and cool it in summer, the job of the hydroponics grower is never done! Keep the air moving gently at all times to maximise the CO2 uptake. Prevent too much leaf movement as this increases the plants transpiration rate (sweating) that in turn will make the nutrient solution strength increase (the water goes, but the nutrient remains). Strong nutrient solution will create "lock-up" in the roots, which means the solution starts to draw nutrient OUT of the plant through the process of reverse osmosis. Maximum air movement, but minimum plant movement is the ideal balance between the two conflicting restraints.