A method of growing plants which has recently been introduced to Britain, although it has been in use for some years in Europe, is a form of hydroponics – that is, growing plants in water instead of compost, with liquid fertilizer supplied regularly. Although initially more expensive to buy, the plants are more likely to grow well, and are less troublesome to look after.
Two containers are required: one in which clay granules are placed-through which the roots penetrate and which help to support the plant, taking the place of the compost-and a lower one in which the nutrient-containing water is placed. The roots grow down to this solution, and feed and drink from it. It has to be topped up occasionally, and replaced completely every few months. There is an indicator to show the need for more solution.
Plants can be bought already growing in these containers, or you can buy the containers on their own, with instructions on how to convert your own plants to them. Not all plants are suitable, though fortunately many houseplants seem to be, especially the aroid family, which includes such plants as philodendrons and monstera.
Philodendron and many other plants which produce aerial roots and grow best in open well aerated compost are ideal subjects for the new systems of hydroponic culture, now available for indoor plants. One of the best systems uses the inert fire treated clay of a selected grade, called Hydroleca. to hold the roots. Up to 7 cm (3 in) depth of water is maintained in the base of the container, water is replaced by watering over the surface of the 13-15 cm (5-6 in) deep Hydroleca every three weeks or so according to speed of uptake.
Plant food is supplied by new fertiliser carrying materials like Lewatit which cannot be applied in excess and one application every six months is sufficient. These new methods of hydro culture remove the two big problems with houseplant care, the difficulty of either over or under watering and the other difficulty of over or under feeding. Hydroponics are likely to see the very attractive P.c. “Burgundy’, which was difficult to grow in soil based compost, take its rightful place as one of our better houseplants.
Far better to grow plants from seed or cuttings specifically for hydroculture in such a way that they develop the special root system which enables them to accept the nutrient solution with a minimum of discomfort. I do this by potting them up after washing the roots free of compost in coarse sand or the material made specifically for the purpose which looks like compressed boiler ash, in granules the size of a finger nail, or vermiculite. The inner pot is made of open mesh plastic, while the container which holds it is waterproof. Usually, after about 5 weeks the water roots are developed enough for them to be put into one of the specially manufactured hydroponic systems. Once made up the system will survive without attention for up to a fortnight, ideal for holidays.