Lithops cultivation



Index



Soil mixes
Pots
A suitable environment
Watering and the growth cycle
Repotting
Pests and diseases
Pollinating your plants
Harvesting your seeds
Sowing the seeds

Taking care of adult Lithops



Soil mixes



The type of soil you grow your Lithops in is very important, and everyone tends to use their own recipes. The soil should drain easily, be mainly mineral based, and should not contain too much organic matter. Your climate also should be taken into account. If your plants are grown in humid or colder climates, drainage is very important, because the water must not remain in the soil for too long. If your climate is very hot and dry, you can have a bit more organic matter, and the soil can be a little more compact, so that the water can remain in the soil for long enough for the plants to absorb the water. When adding compost to your mix, you must ensure it is decomposed properly. I would suggest that you sieve your compost to remove any larger particles. The type of soil mix you use is also affected by your watering regime, and must be kept in mind. If you water your plants frequently, then a mix which retains water for too long can be a problem. If you grow your plants hard, a soil mix which has hardly any water retentiveness, can be a problem, even though Lithops are pretty drought resistant. I would recommend that you try stick to the same recipe every time you mix your soil, so that your drainage is a constant. Rather adjust the watering and fertilizer for finer control of the individual species needs. One of the best soils to grow Lithops in is decomposed granite, but this is not always easy to obtain. Too much fine silty sand can be a problem, because it has poor drainage. If your sand is fine, you will need to add some grit, pumice or perlite to the mix. Fine clay based soils are also not a good idea because there is not enough air present, and I have also read that clay has a very strong bond to water molecules, which makes it harder for the plants to "pull" the water from them. In habitat the soils are fairly fine, but in cultivation fine soils can be tricky to work with. It is easier to give more water than it is to take it away.

Below is the mix I tend to use:



4 Parts fine river sand
4 Parts coarse river sand
4 Parts sieved compost
1 Part perlite
1 Part vermiculite
1 Part coconut fibre

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Pots



Now that you have your soil, you must find a suitable pot. You can use either plastic or clay pots, each has its pros and cons. Clay pots are more porous, and allow the soil to breathe more easily. The soil in clay pots also dries out a lot faster, so you need to bear this in mind when watering. They are more expensive than plastic pots, so often your choice might be decided by your budget. Clay pots also take up more room, so they are not practical when your space is limited. Plastic pots are used by most people, and I find square pots the best. The size of your pot is also important. Lithops in the wild have fairly long roots, so deeper pots tend to work better for adult plants. A good size to go for is a pot measuring 12 cm X 12 cm X 12 cm. They give your Lithops enough root depth, and are also not too heavy. I tend to go for terracotta coloured ones, rather than the cheaper black ones, because they don't get so hot and one can also write on them (I write the name of the species on the pot as well as the label for extra security).

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A suitable environment



Lithops in their natural environment receive a lot sunlight, and if you want plants that grow fairly flush with the soil like those in the wild, they should be exposed to at least 5 hours of sunlight a day. They can however be grown perfectly well given less sunlight, but they will tend to grow taller than they would do in their natural habitats. The ideal spot is one which gets good sunlight in the afternoon. This said, they are also sensitive to too much direct sunlight in certain climates, and should not be placed in an area which receives full sun all day long, unless they are given a little shading in the form of shade cloth overhead (20-40 % shade factor, depending on how harsh your sun is). If you are in an area which does not experience harsh sunlight like many of the areas in the northern hemisphere, shade cloth is most likely unnecessary. This might seem odd, considering the fact that they grow in full sun in the wild, but there are various factors that are different in cultivation. Firstly, Lithops growing in the wild, are not grown in pots, so the soil remains a lot cooler than the soil in pots, and secondly, plants in their natural habitats receive protection from the sun via shade from the surrounding rocks and plants. Plants in their natural habitats also tend to grow on hillsides, which are in shade for some of the day. Ventilation is also extremely important. Good airflow keeps the temperatures down, and reduces the humidity in the air, especially in the greenhouse environment. Lithops should not be grown outdoors, unless your climate is one that is similar to their natural habitat. Lithops grow in very arid parts of Southern Africa which receive very little rainfall, and need to be protected from receiving too much water, especially if you are in an area which receives rain in their dormant season (just after flowering and while they are absorbing their old leaves and developing new bodies).

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Watering and the growth cycle



Lithops in the southern hemisphere grow mainly in areas that receive their rainfall in summer (October to March). Those that do grow in areas that receive some rain in winter, do not get much rainfall at all, and tend to get most of their moisture from condensation of fog (L. herrei, L. optica and L. ruschiorum).

Lithops have quite a large distribution area, and the range of climatic conditions is fairly broad, so it is not easy to give an exact schedule that suits all of the species. One can however follow some basic guidelines by bearing in mind their growth cycle. Just after the plant has flowered (March to April mostly), and once the temperatures start to drop, one can start reducing the frequency of their watering, but not the amount of water, giving them their final soaking in early May. After this they should not receive any heavy watering at all, until late September or once their old leaves have been absorbed completely. It is during this time that the new bodies develop inside the existing ones. The new body absorbs the moisture stored in the old body, and as it does the old body dries up, eventually becoming a paper thin shell. If one waters the plant too much during this period, the old body does not get absorbed, and can end up restricting the new body from forming. It is referred to as the dormant season, but it is actually a period of renewal and growth. It just appears as if nothing is happening, but in reality there is a lot going on inside the shrivelling body. This new body will eventually break out of the old body in spring, when the rains return. During the so called dormant period one should give the plant no water, except for the odd misting, prefferably on warmer days, or maybe once a fortnight or so (if you live in a colder climate misting is not a good idea). Once the new body has fully emerged, you can start to water more deeply again.

As a rough guide, one can water the plants about once every two weeks during the summer, but this depends on the soil mixtures you are using, the humidity levels, and the temperatures. The best way to work out if a plant needs water is rather to observe the plants, and get to know the telltale signs. One can generally see if a Lithops needs water, when it starts to retract into the soil, or when its leaves start to wrinkle when it loses its stored water. During the hotter summer months one can also spray the plants with a mister in the early mornings or late afternoon, but just lightly to cool the soil and stimulate the small roots that catch the condensation that would occur in their natural habitats. When you give them their proper watering, you must ensure that you give them a good soaking so that the water reaches their roots (but don't overdo it either). Many people often think they are giving the plant enough water, when in effect, all they are doing is wetting the top of the soil. It is not an easy thing to get the balance right, but in time you will know what to look for. Observation is the key, the more you look, the more you will learn. For people in the northern hemisphere, plants will adapt to your seasons, so you must follow the seasons you have, and not the ones in the southern hemisphere.

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Repotting



Every two years or so, your Lithops will need to be repotted. It is good to do this so that their soil can be renewed. The best time to do this is just after the new body has emerged, and the old body has completely dried up. After they have been repotted, it is advisable to give them a little more protection from the sun for the first two weeks at least, because the repotting can damage the fine roots, and reduce the plants ability to absorb water effectively. This can also affect the plants ability to reduce its internal temperatures, and it can overheat.

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Pests and diseases



Lithops, like all other plants, have their predators, and one has to be on the lookout for them at all times. The most common problem is the Mealy bug, which feeds on plant sap. They are usually found in places where they are difficult to spot, like on the roots, and in the cleft, after it has been opened by the flower bud, or in the spaces between the old leaves and the new bodies. They tend to favor warm, humid conditions, and this makes plants grown in greenhouses particularly vulnerable. They attach themselves to the plant, and while they feed they secrete a powdery wax layer, which acts as a form of defence against their predators. This waxy substance also repels water, so insecticidal sprays tend to be ineffective. There are some insecticides which can get rid of them, but they are usually pretty poisonous, and I tend to try avoid their use. A less harmful way of dealing with them is to use a paintbrush dipped in medical alcohol, and literally paint them off. The alcohol dissolves their waxy coatings, and kills the pest. You must however ensure that you spray the plant with a bit of water immediately afterwards, or the alcohol will damage the plant. If they are attached to the roots, the plant will need to be removed from its pot to do this effectively. Other insects which attack Lithops are more easy to spot, like various caterpillars and crickets, but growing plants on raised staging tends to limit their access, and they are not really much of an issue. Rodents also like eating the fruits of Lithops, and sometimes the plants themselves, but can be kept out of the greenhouse fairly easily. Lithops can also be infected by bacterial and fungal attacks every once in a while, but this is not very common, and is usually due to incorrect soil mixes, or high levels of humidity. Every once in a while the odd plant can succumb to what is known as sudden rot. Plants without warning loose their pigmentation, and turn all soft and collapse, their insides turning into a watery yellowish liquid. It does not happen very often, and there is not much warning when it does. One can use fungicides, but I try avoiding them as much as possible.

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Growing Lithops from seeds



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Pollinating your plants



Lithops are self-sterile, so one needs two plants for pollination. These plants must be separate plants, and not two different heads from the same plant. The flowers last about a week and are at their most fertile after about four days. It is also important not to wet the flowers during flowering, because this destroys the pollen. To pollinate them, you need a small brush, preferably made of natural fibre like sable hair. You remove the pollen from the anthers of the one flower and transfer it to the stigmas of the other flower. If you are pollinating more than one species, and do not want to do any cross pollination, then it is best to sterilise the brush before moving to a new species. This can be done by dipping the brush in medical alcohol.

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Harvesting the seeds



If you were successful at pollinating your Lithops, you should see a seed capsule begin developing within a few days. The capsule must be left on the plant until it is dry and no longer green. This takes a few months and they tend to be ready just after the new bodies emerge from the old ones, in time for the rainy season in their natural habitat. You must try not to get the capsule wet at this stage, because this will cause it to open, and you then run the risk of losing the seeds. To remove the capsule, you can use a pair of nail scissors to get between the capsule and the plant. and cut the dried out pedicel. It is quite a tricky process to do, and you must be carefull not to damage the plant itself. To get the seeds out of the capsules you can either crush them lightly with your fingers, or you can place it inside a coffee filter paper and immerse it in water, just enough so as to get the capsule wet. After a short while the capsule will open, and you can then scoop the seeds out of the capsule. Once all the seeds are out, remove the filter paper from the water, and allow it to drain. Once the paper has dried you can scrape the seeds off the paper.

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Sowing the seeds



Growing Lithops from seed is very rewarding, and is a good way of building up a collection. The best time of year to sow Lithops depends on your climate and the conditions where you are growing them. The most important factor is that they get enough warmth. If it is too cold they will not germinate and if it is too hot the young seedlings might overheat. Some people prefer to sow their seeds in spring, while others prefer to sow them towards the end of summer once the heat has subsided. They can also be sown under lights at any time of year, but must be sown in a well ventilated environment. Plastic pots measuring 10 cm in all directions work well for sowing batches of individual species, and can easily accommodate from 20-80 seedlings. It is advisable to sow each species in its own pot. The ideal medium to sow Lithops in must be mainly mineral based, and should contain very little organic matter. The mixture suggested for adult plants can be used, but should be sieved through a wire mesh with 2 mm holes. Your mixture should be sterilized by placing it in an oven for a few minutes, and allowing it to cool for a while afterwards before you sow the seeds. The soil should be lightly compacted by tapping it on the floor. You can also use a wooden block cut to the same dimensions of the pot to compress it. After this you can place a very thin layer of coarse sand of up to 3 mm in size on top, but not too deep, just enough to cover the surface. This anchors the seeds, and reduces the chances of any algae forming on top of the soil. You can then sprinkle the seeds as evenly as possible on top of the soil. The seeds are quite small, so what I tend to do is place them in a small piece of paper that is folded in half, and spread them around. If you are sowing a lot of seeds at one time, you can also put them in a salt shaker with a little fine sand, and sprinkle them onto the soil. Once the seeds have been sown, you can sprinkle a bit of fine sand very lightly over the top, but once again only enough to just cover them. If the seeds are sown to deep below the surface, they can end up rotting. Each pot must be clearly labelled with all the data you have. I write the information on the sides of the pot, as well as on labels, to ensure the information is not lost. The pot can now be placed in a shallow tray of water wich has a little fungicide added. The water will be soaked up by the soil, and when it reaches the surface, you can remove the pot.

The pots must be placed in an area which receives good sun, but must be given a bit of shading. Shade net with a shade factor of about 40% works well. Ventilation is also important, and a fan can be used to help. The moving air reduces the chances of fungal infections, and keeps the seedlings cool. For the first few days the pots can be covered with clear plastic or a sheet of glass to keep the moisture from escaping to rapidly. The glass can also be raised slightly to avoid the air becoming stagnant. Within a week or so the seedlings should start to emerge, and once they do, you can remove the cover. For the first three or four weeks you must keep the soil fairly damp, but not soggy. To keep the soil moist, one should spray them with a mister at least twice a day in the morning and afternoon. Heavy splashing can disturb the seeds and seedlings, and is not a good idea. After about three to four weeks your seedlings should be fairly well developed, and healthy seedlings tend to be have a slight red tinge, and should not be too green and tall. You can now slowly start to reduce the frequency of their watering. After three to four months the cotyledons should be quite fat, and they will start their first leaf renewal. The new bodies when they emerge will start to take on the characteristics of their adult counterparts. Throughout their early development you can give them a bit of diluted fertilizer, added to their water. The seedlings must be left in their pots for as long as possible, and I tend to leave them for up to two years, unless they are really overcrowded. This also is a way of natural selection, and the smaller weaker ones tend to die, leaving only the stronger, healthier plants. One must try not to give them too much water and fertilizer once they are past the early development stage, because if they are over stimulated they can become more prone to disease. When the young plants are ready for repotting, you can gently tip the contents of their pots out and separate the plants. They can now be given the same treatment as adult Lithops.

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