Capillary water is the water that remains in the soil after the water drains; it permits plants to survive through periods of drought. The Treesolution notes that capillary water is equally as important as condensation or rain.
The construction of the "Groasis waterboxx" utilizes capillary water; it uses a cylinder in the middle of this waterboxx. The roots of either a tree or a plant can be placed inside this instrument in as little as 5 cm of soil. After only one day, root hairs begin to develop in the undisturbed soil, where capillary water is located. The large amount of capillary water assists the tree or plant to begin growing sooner.