Hydroculture-vulture

Enthusiast Ulrich Gramm of Germany explains a completely new approach to growing palms, entirely without soil.
Ulrich Gramm, Gellertstr. 42, 7500 Karlsruhe 21, Germany
Chamaerops No. 10, published online 23-09-2002

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The proof of thepudding... Growing well in Hydroculture: Clockwise, from top left: Rhapis excelsa, Aiphanes caryotaefolia, Chamaedorea seifritzii, Washingtonia filifera.

Hydroculture - what is it?

Simply put, hydroculture is a method of growing plants without soil. Usually the plant is supported in a perforated container, by clay granules or similar. This container is then put inside another, which contains nutrients dissolved in water. The roots grow through the perforations in the inner pot and into the feeding solution. Because the roots don 't need to 'search' for nutrients, they stay much smaller, and the need for frequent re-potting is largely eliminated

Beginnings.

My interest in palms began about 10 years ago. At that time, cultivation in hydroculture was not very common and only a few such plants could be found for sale. The 'rarity' and this more hygienic way of keeping plants were the main reasons for my decision to go over completely to hydroculture and to grow all my palms that way. I started out by buying all the species commonly available at garden centres: Phoenix canariensis, Howeia, Chamaedorea and Chamaerops. The palms were then cleaned of soil ready for the transfer to hydroculture. Depending on the type of soil and the density of the roots, some roots were broken in the process, resulting in only 60-80% successful change to hydroculture. It seemed then that starting from seeds might lead to more success, and I started collecting them while travelling, I also bought seeds and seedlings in Germany. Germination of seeds bought here was not very satisfactory and salesmen not very competent, thus more than once seeds were bought with the wrong name. My current collection is based now on seeds which I collected myself, or which I had friends collect. Having collected the seeds, the sowing and subsequent cultivation in hydroculture poses its own problems, dealt with in the following way.

Germination.

I began by attempting to germinate the seeds in the finest grade clay granules, which almost always led to rotting despite using distilled water. A uniform moisture level in flat seed trays is almost impossible to achieve with these little pebbles! These days all seeds are now sown and germinated in sterilized potting compost.

Potting Up.

Potting up means great change for the seedling when it leaves the warm and moist germination tray. The best results seem to be achieved in summer; potting up in winter is only recommended for the more cold-tolerant species. Another stress factor for the young plant is the change from soil- to hydro-culture. The root(s) should be completely cleaned of soil in warm water, care being taken not to separate the seed if still attached. The plant is then positioned in a small hydroculture pot, just large enough to accommodate the roots. Great care is necessary to avoid damaging them as the expanded clay granules are added to the correct level, and water is added to the mark indicated on the water gauge. No fertilizer should be added for the first four weeks, though regular spraying with tepid water will help the young plant to settle in.
The first months. After about 4 weeks a hydroculture fertilizer should be carefully applied. These are long-term fertilizers and should last for 4-6 months. Make sure the water indicator does not clog up and give a false reading, as too high a water level can be dangerous, especially in winter. Small pots evaporate quite a lot of water, which leads to a build-up of salts and calcium on the upper surface of the pebbles. This in turn can accumulate moisture around the base of the plant; moss and mould can form which can cause the plant to rot at the base. Should this occur, clean the base of the plant and exchange the top layer of pebbles. They can be re-used once decalcified and sterilized.

Re-potting.

By the time re-potting is due, the plant is already sturdier and easier to handle, and the problem of base rot will be lessened because of the greater distance between the surface of the water and the top of the pebbles. Old, dead roots should be carefully removed at this stage.

Seasons.

Many temperate or subtropical palms such as Phoenix, Butia, Trachycarpus, Sabal, Nannorrhops, Chamaedorea, Howea, Rhapis and many others can spend the summer outside, but in hydroculture. A few additional problems are posed. After heavy rain, the pot should be checked as the water level may have risen too high. A sheltered position is advisable. If frost is expected, even hardy palms should be brought in due to the danger of the water freezing and with it, the roots.

Differences in growth.

Concerning the rate of growth quite significant differences were noted between soil- and hydro-culture. Some species, Washingtonia for example, grew considerably faster than in soil, while others, such as Chamaedorea were slower in hydroculture. No predictable pattern has emerged so far.

Translated from German by Tobias Spanner

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