In heating the clay to a very high temperature, the granules develop extremely fine holes running inside them. When immersed in water these fine holes, draw up and store water in the granules using capillory action. The granules can hold up to a third of their own weight in water.
The hydroponic system is based on five essential parts: the hydroculture pot, a water-level indicator, a special hydroculture fertiliser and a container for the hydroculture pot. The hydroculture pot has slits in the side of the pot as well as underneath to allow the air and water to circulate.
Young plants bought or grown indoors or in the greenhouse and grown in compost can be transferred to the hydroculture system. Ideally the young plants should be at the stage where they need potting up. Plants well rooted in a 87 mm (3 1/2 inch) pot would be ideal.
Prepare the hydroleca granules by soaking them in a bowl of fresh tap water to wash off dust accumulated around the granules. Leave the granules to soak in the water while preparing the plant.
If buying a plant, start with an inexpensive one. Alternatively, a cutting taken off one of your own plants and rooted in a 87 mm (3 1/2 inch) pot of conventional potting compost. For example house plant Dracaena Kiwi would be an excellent choice.
Prepare the plant by carefully tipping it out of its pot onto a sheet of newspaper, then remove the soil around its roots. When most of the soil has been removed, wash the rest off in lukewarm water. It is important to remove all traces of soil from the plant as the hydroculture method relies totally on the roots being in contact with the granuales and water. Soil will contaminate it.
When the roots are clean, the plant can be transferred to the hydroculture pot. Hold the plant over the pot and gradually fill it with granules, spreading out the roots as far as possible. Ensure that the same amount of the plant that was above the top of the old pot is also kept above the new one. Fill the pot to the rim with granules. Tap the pot on the work surface to settle the granules down as the pot is filled; no firming down is necessary.
Fit a water level indicator if the pot has provision for one. Then place the pot in the outer container.
Stand the hydroculture pot on a layer of granules in the container to make both their rims levels. At this stage it is not advisable to fill the gap between the pots with granules until later when fertiliser has been added. If you do not have a water level indicator it may be useful to leave this gap open or only partly fill it later to check the amount of water remaining.
For the plant to adapt successfully to its new conditions, it needs three essentials: water, oxygen and a comfortable temperature of about 18 degrees C (64 degrees F). Keeping the water no lower than MIN on its water-level indicator, will ensure plenty of water, and no higher than MAX, will ensure air with its oxygen around the roots below the surface of the pots. The capillary action of the granules will ensure the roots above the water level obtain plenty of moisture. A reasonable temperature can be obtained by carrying out the transfer during the warmer months of the year, namely in summer or late spring, early autumn. Otherwise artificial heat should be provided to give sufficient warmth for continued growth of the plant after settling into its new environment.
It is advisable to ensure that the plant is kept moist for the first two to three weeks whist it establishes its water roots and adapts to the change. A moist atmosphere around the plant can be established by placing a polythene bag over the plant. Place the plant in a position where it will receive shady sunlight.
After a fortnight feed with a hydroculture fertiliser. When applying the fertiliser adhere strictly to the instructions supplied with it. It is important to use only the special fertiliser formulated with nutrients selected for hydroculture. Any other fertiliser will not encourage the plant to grow so well under these conditions and will also most likely cause a large growth of algae.
The fertiliser needs to be dissolved into the water that surrounds the plants roots. Pour the fertiliser down the gap between the hydroculture pot and outer container or by lifting up the pot and sprinkling the fertiliser in the water underneath.
Hydroculture Plant Arrangement
Plants grown using hydroculture can be arranged in a display which can be easily maintained. Before starting the arrangement, transfer the plants into individual hydroculture pots as already described. Select a container without drainage holes that is slightly deeper than the height of the hydroculture pots. Soak a sufficient quantity of hydrolea granules to fill a layer at the bottom of the container if necessary and to fill in around the pots.
Use a spare pot to see if there is a difference in its height and inside height of the container. If there is a difference, place a layer of granules in the bottom of the container. Build up the layer, until the hydroculture pot can stand on it with the rim of the pot level with that of the container.
Ensure that there is a water level indicator attached to one of the pots to indicate that the right amount of water will surround the plants roots.
Stand the first plant in its hydroculture pot in position on top of the layer of granules in the container and add further granules if necessay to hold it in plance. Then place the second plant in position and repeat the process if there are any other plants.
When all the plants in the hydroculture pots are in position, fill the spaces between the pots and the container with granules until they are level with the top of the container. Filling the container to the top with granules, will give the display an attractive finished appearance. One or more stones, washed clean of all dirt, could be added to give contrast and additional texture to the final arrangement.
After completing the display, ensure it is kept moist for the first fortnight. If enclosing the display in a polythene bag to keep it moist, ensure the bag has air holes in it in case it is misused. After a fortnight apply the special hydroculture fertiliser according to its instructions.
See Hydroponic supplies and plants here