L i t h o p s C u l t i v a t i o n
For the past 20 years that I have been growing Lithops I have tried various soils, temperatures, shadings etc. and I ended up with a way that at present works best for me. This will be outlined here briefly. It is important to know that it works for me under conditions here in the very west of Germany and it may not work best elsewhere.
Lithops are usually grown from seed. They can be propagated from cuttings but rooting them is more difficult than it is with Conophytum. Furthermore this requires large plants to take cuttings from. As Lithops grow slowly and do not multiply heads every year large old plants are rare and valuable.
Sowing Lithops in autumn is rather easy. Seed is best stored for at least one year as fresh seeds may germinate too irregular. Lithops seeds keep viable for at least 10 years if stored in the fruit in a dry dark place.
For sowing it needs a free draining mineral substrate. I use pumice with no ingredients at all but if you have no access to pumice any stone gravel of 1 – 4 mm size will do if the pH-value is not above 7. I strictly avoid to use any peat or pot ground as most pests need this to survive. Furthermore all very fine particles are avoided to make sure that seedling roots can grow into the soil directly instead of creeping over the soil. Before sowing the soil should be sterilized to avoid any weeds to germinate. This is easily done in an oven at 200°C for one hour. This is filled in pots or trays and made completely wet with rainwater. If tap water is used it should not contain calcium. Seeds are scattered on top of the wet soil. Seeds are not covered with soil. Optimum density is about 10,000 seeds per square meter. Pots or trays are covered with a thin plastic and kept in a shady place at a constant temperature of about 15°C (not over 20°C). A windowsill in a temperature-regulated room gives better germination than a sowing in a greenhouse. It is too hot and too sunny there and days are warmer than nights. After two weeks germination has finished and the containers can be uncovered.
Seedlings are sprayed several times a day and will not be allowed to dry up at all for the first few weeks. More light is given very slowly and full sun during hot days is avoided for the first year. No chemicals of any kind are used for sowing. No fertilizer is given before seedlings are one year old. As plants grow larger they can have more light but on hot sunny days Lithops require shading all their life. If you live in a sunny climate this may not be needed but after a dark German winter Lithops will die in full spring sun within an hour.
Lithops can be grown under permanent shading as it is done in large nurseries but plants grow fast and large and tend to become long and soft. Coloration is very bad under such conditions. If you have ever compared a fat green Lithops dorotheae with a small natural one with black-red markings on an orange-yellow body grown in full sun you will know the difference. This is why I give shading during hours necessary only.
Lithops need very little feeding. I use liquid fertilizer (Wuxal Super, N:P:K = 8:8:8) 2 – 3 times a year during growth. I tend to water more than most growers do but to be on the safe side I suggest not to water during hot summer conditions and I keep them dry from February till March.
Pest control is done by one treatment of Imidachloprid (trade name Confidor in Germany) per year during plant growth. That’s it. No other chemicals are used. If any trouble occurs conditions need improvement.
Except for the germination process itself Lithops like warm days and very cool nights. In winter I keep them under automatic frost protection but this has failed a few times and no Lithops has died at -6°C for two nights in a row.
Lithops grown slowly under maximum light will flower for the first time at three years of age. One can do it within one year but there is little chance to get them through the next winter. One can easily make his own seeds. If you like surprise let insects do the job. If you like it true to type keep insects away and take a paint brush (a different one for any item please!). Most any Lithops can be crossed within any other one and insects do not care at all.
Lithops grown in small pots may need repotting every few years but if they grow in larger trays they can stay there for many years untouched provided watering is done from above and excess water can just run away. Again I use pumice for all potting. During repotting all roots are cut away except for a 2 – 3 cm rest of the main root. This way plants make new roots much faster and it is assured that roots are straight in the new pot. A plant with a long root potted bent dies slowly.
You can clean heads from old sheaths but If one has old plants with thick layers of old sheaths it is safer to keep them on the plant. Otherwise heads easily break off. If this happens put broken off head into soil immediately, make it moist and keep it below 15°C.
In this short article I have rather mentioned different aspects than described them in detail. Any reader wishing more information feel free to get in touch with me in German, English, Dutch or Afrikaans. Sorry no French.
Fon: +49 2655 3614
Fax: +49 2655 941510