Cultivation hints

Mesembs cultivation

The main distribution area of Mesembs is South Africa and Namibia and here especially in the winter-rainfall-area along the west coast. Many Mesembs (e.g. all Conophytum, Argyroderma and Cheiridopsis) are used to get rains in winter thus belonging to the short-day-plants. In the northern hemisphere the start to grow as days get distinctly shorter in late summer and fall. Long-day-plants (e.g. Lithops, Faucaria or Glottiphyllum) have an additional growing period in spring.

Light

As with most all Succulents Mesembs need high light intensities all year round and should not be staged underneath benches or hanging pots. In contrast to nature plants will get sunburned rather quickly in cultivation because of a lack of sunlight during winter causing deficiency in protective pigments. High loss may occur especially during the first hot and sunny days in spring. Do shade your plants but only during hours necessary. Proper ventilation and good feeding will lessen burning danger.

Watering

In nature parcipitation ranges from > 2,000 mm/a in the south to nearly zero in Namibia. Especially in the dry regions plants depend on water from fog occurring there most any day in the morning. Plants can uptake the water through very fine roots close to the surface. Daily misting as many people do will only be useful if done early as the plants need hours to take up the water. Spraying at 8:00 in the morning in summer is nonsense as the water will be gone within minutes. So if you don't like to get up at 3:00 forget your mister, take your can or hose and give plenty of water whenever your pots get dry. If you keep Mesembs dry during their resting time there will be high loss but very little if you water them.

The water should be free of calcium and at least as warm as the substrate. On a warm summer evening your water should be 25° C. Do water from above and several times a year so strong that most of it runs away through the bottom holes of your pots. If not, salts and other poisonous materials that plants give into the ground via their roots will accumulate and will reduce both growth and the beauty of your plants.

Nutrition

As with all plants Mesembs need nutrition. All macro elements (N, P, K) and microelements (Mg, Fe, Fn, Bo, ...) must be available in the quantity necessary. They must also be present in soluble form so that the plants can take them up. It is useful to give a microelement feeder into the potting mix anytime you transplant (every 2 - 4 years) and a high nitrogen liquid feeder on low concentration several times a year during the growing season. You will have a regular and constant growth if you feed frequently on low concentration.

As substrates you may use any well draining materials on particle size between 1 and 4 mm. Avoid any dust, especially loam. The latter will kill any plants with time. We use pumice. Check your pH-Level! It should be between 6 and 7, never > 7.

Lithops cultivation

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 December to around April.

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.

Lithops cultivation under tropical conditions

In their natural habitats Lithops have warm or hot days but cold nights down to freezing point and day length is short in winter and long in summer. This is what Lithops naturally are adapted to. Here in Germany it is similar. The main difference is that in South Africa and Namibia where Lithops grow it is sunny most every day but here a sunny day is an exception and winters have times of strong frost.
Although I have no experience myself growing Lithops in tropical countries where it is hot day and night, humidity is high and day length is similar winter and summer. I have several customers in different tropical countries who have tried. It turns out that Lithops rather easily adapt to very different conditions.

They do need a period of short days once a year that should last for two months at least. This can rather easily be achieved by giving normal daytime conditions for some hours and covering them for the rest of the day to make it dark. For doing so start at the given 12 hours daylight and reduce this by one hour per week until you reach 8 hours daylight. Keep this for a few weeks and increase again by one hour per week until you are back at normal conditions. This simulates a winter and makes sure that there is the needed resting time. It also ensures that flowering occurs. If you have 12 hours daylight all year round your plants will always grow but they will not survive this for longer than 2 – 3 years and it is unlikely that you will see flowers.

The most difficult aspect is high night temperatures. Lithops are used to night temperatures between zero and 10°C all year round. You do not have this at all. I know of someone who puts his Lithops into a refrigerator during night. This works but if you hold a large collection this of course is rather a joke than reality.
Try at least to give as much air circulation and use the coolest place you have. Some light spray with water also makes it colder for the plants. This however again increases air humidity and this is too high anyway. Be creative as there is no limit for ideas. For any other aspect of cultivation I see no difficulties.

Lithops live in arid conditions so they will need rain protection. Take care not to increase temperatures and humidity by giving this. Just some roof, no side glazing. Make sure soil dries out before next watering.

Shading might be necessary especially if you acquired new plants grown under different conditions. Protect them from too much direct sunlight until they got used to.

Sowing in autumn might be difficult as germination decreased as temperatures get higher than 20°C. (shady place, 15°C)

A plant usually tells you what is wrong. If bodies burst it is too wet all the time. Make it as dry as you can. If the new bodies push through the old ones before they have dried out they grow too fast and the dormant period is missing or too short. If no flowers occur it again is a matter of day length.

If rotting is a frequent occurrence, do all you can to reduce humidity. Give best possible air circulation and avoid any organic matter in your potting mix. Any fine stone gravel will do as long as its salt-content is not too high. Using fungicides should only be done if any improvement of conditions fail.

There is one main advantage that you have. You don’t need any greenhouse that needs most of your income to heat them through long dark frosty winters.

There is no reason not to try these plants and I would be very glad for any communication on whatever experience you have made.