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Growing Lithops

Eric Collins, Oz Lithops.

(You are not permitted to reproduce or publish this document in print or electronic form without written permission from the author, except for your own personal use)

This “guide” to starting and growing Lithops is intended as just that, a guide. This information is provided with over 20 years experience of growing Lithops and other Mesembryanthemum but what works for me might not work for you. There is lots of information, both good and bad, available on the Internet and whilst you may find differing information, this is what I do and it works for me. Although intended as a guide to Lithops, a lot of other Mesembryanthemum can be grown using the same materials and conditions as Lithops.

There are a couple of basics that you should know and first of these is the name “Lithops”.

• Lithops is both singular and plural, just like sheep. You can have one Lithops or many Lithops, just as you can have one sheep or many sheep. Please don’t use the term “lithop”, you simply cannot have a single “lithop” as there is no such thing!

• The name Lithops comes from ancient Greek, (lithos), meaning "stone," and (ops), which means "face". Hence the common names of “Living Stones” and “Flowering Stones”.

Secondly, Lithops will grow in just about anything, but some materials are better than others. Whatever materials you use, they should be in a variety of sizes from “small” to “large” and not just one consistent size.

This guide is broken down into sections so you can look at only the information you are looking for or, preferably, read the entire guide and take what you will from it.

Sections:

1. General Information

2. Pots

3. Potting Materials

4. Lighting

5. Watering

6. Starting Seeds

7. Observations

8. The Last Word (some other information)

1. General Information about growing Lithops.

As a general rule, the natural habitat of Lithops is primarily hot, arid country but there are exceptions and the various species have made their home in grassland through to barren rock and in habitat they do not grow outside their particular environment. One or two grow in coastal areas where the temperatures are cooler and more stable and some reside in areas of such low rainfall that they survive primarily on dew. The common denominator is that all Lithops require a very well drained substrate which is usually very low in nutrients.

The materials used for growing Lithops in your particular situation depends on many variables that only you can determine. Amongst these variables are the type of pots used, ambient temperatures, humidity, air flow, composition of the mix used and the growing area.

Broadly, countries or areas where the temperature is generally higher, a mix containing a larger proportion of organic material may be used whereas those where the overall temperatures are colder, a pure mineral mix may be used. The only downside of using a pure mineral mix is that some fertilising may be required. Areas of constant high humidity are not conducive to growing Lithops, however most people will find somewhere Lithops should grow, even if not perfectly.

As an example of the above, my nursery reaches temperatures of over 55C in the height of summer when the ambient temperature is around 43C. I use large (750mm) wall fans to circulate air and also have openings in the nursery that are covered by 50% shade cloth to allow air from outside the nursery. Good air flow helps to reduce leaf temperatures and also assists in keeping disease and insects under control. My mix for Lithops contains 30% organic material and my Conophytum mix has 50% organic material.

I have seen “diagrams” about the cycle of growth floating around the Internet and whilst some are good, there should be better clarification regarding active growth, “dormancy” and seasons. In Australia, the four seasons are opposite to those in the Northern hemisphere (and we also use a different name for autumn than some countries!). In short, these are the seasons:

| |Southern Hemisphere |Northern Hemisphere |

|Summer |December, January, February. |June, July, August. |

|Autumn (or Fall) |March, April, May. |September, October, November. |

|Winter |June, July, August |December, January, February. |

|Spring |September, October, November. |March, April, May. |

Conditions during these seasons will depend on how close to the equator you are. South Africa and Namibia, the natural habitat of Lithops, enjoy summer rains and a dry winter. South Australia is roughly on the same Latitude as S.A./Namibia. Once again, there are variables and some areas receive some winter rains and some coastal locations receive rain all year round, albeit in small quantities. Lithops growing in or near coastal areas rely more on sea fog and mist than actual rainfall and optica is typical of this. To further complicate the watering regime, the optica’s also tend to be out of sync with other Lithops by some four months!

The following table is the general growth cycle of Lithops:

|Summer |New leaves are fully grown, old leaves are dry, flowers open. The earliest flowering species are |

| |pseudotruncatella (December – beginning of summer). Water only on cool days otherwise you can turn your |

| |plants into "Lithops soup"! Although not actually dormant, Lithops do not need tremendous amounts of |

| |water during the very hottest times as they are normally preserving against transpiration. Plants that |

| |are shrivelling badly should be lightly watered, again only on a cooler day or very early in the |

| |morning, not in very high temperatures. |

|Autumn (or Fall) |Flowering finishes and seed sets. Continue watering but taper off as the weather cools. |

|Winter |Although Lithops may be regarded as "dormant" during winter, they are in fact growing the new leaf |

| |pair(s) inside the plant by utilising the old leaves for water and nutrition. DO NOT WATER. |

|Spring |New leaves will have emerged and the old leaf pair will be drying to eventually be no more than a husk. |

| |The plant is preparing to flower. Commence watering on warm days. |

The exceptions to this cycle are the optica’s as they generally flower in autumn (fall) and the old leaves take longer to dry off. Watering optica can be regarded as a light misting rather than a heavy watering and can be done more frequently. This simulates the coastal conditions they inhabit more closely.

2. Pots.

The choice of pots will also determine the frequency watering is required. Plastic pots, which are what I use, will need less watering than unglazed terracotta pots. Smaller pots require more frequent watering than large pots. Temperature also determines how often watering is required – constant higher temperatures will more often necessitate watering more frequently. Lithops have a fairly deep tap root and deeper pots are better than shallow pots or trays. However, Lithops started from seed can easily be grown in a 55mm pot with a depth of just 50mm for around three years before they will need to potted into something deeper and wider. I use both 55mm and 63mm pots to start seeds in, depending on the number of seeds I am planting. On average, a 55mm pots is used to start 20 seeds.

All my adult plants are growing in 95mm square pots that have a depth of 130mm. When potting from seedling size to these pots, I often plant one to five plants in the same pot, evenly spaced, where they are grown for anything up to 8 years before being potted individually.

3. Potting Materials.

Regardless of what pots and the composition of your mix for growing Lithops, it is absolutely essential that your growing medium and pots are very free draining. The use of fertiliser is only necessary in extremely small quantities and generally then only if you use a mix that is entirely made up of inorganic material(s).

The list of materials in table 1 is made up of two sections, inorganic and organic. Those in the inorganic section are materials that derive from rocks in one form or another. Some are manipulated by man and others occur naturally. Organic materials are those that derive from plants, in one form or another.

The amount of organic versus inorganic material in your mix will vary depending on factors such as the genus (Lithops, Conophytum etc) you are growing, the pots you use, ambient temperatures and of course, availability. Some materials are more expensive than others and some are simply not available in some countries.

INORGANIC MATERIALS – Not all useful materials are listed. You may find something that is suitable close to you. It is not the intention of this guide to tell you what you can or cannot use however experience has told me that some materials are not as good as others. Quite a few of the materials listed have not been trialled by me and some have been used in the past but are no longer used by me for one reason or another.

ORGANIC MATERIALS – Included here are commercial potting mixes because although they include inorganic materials, they generally contain organic materials in high proportions, far more than is required for Lithops and other Mesembryanthemum. Most of these materials are readily available everywhere.

|TABLE 1. |

|INORGANIC |NOTES |

|“Aggregate” |A broad term used to describe a combination of inorganic materials such as sand, gravel, |

| |crushed stone and slag. |

|“Akadama” |Volcanic, clay like mineral. Originates from Japan and is widely used there when growing |

| |Bonsai. Not readily available - refer to scoria. |

|“Aquarium Gravel” |Pea gravel of various sizes, usually painted or dyed. Not recommended as this is also |

| |often made of plastic and the smooth surface is not ideal. |

|“Buckshot” |See Pea Gravel. |

|“Chick Grit” or “Chicken Grit” or “Shell |Mostly oyster shell, high in calcium. May be suitable but I have never used this |

|Grit” |material. Some “Chick Grit” is composed entirely of decomposed granite and this is |

| |suitable so you should check the ingredients. |

|“Gravel” |A loose aggregation of rocks. (see also Pea Gravel, “Buckshot”, “Aggregate”) |

|“Kanuma” |Volcanic mineral, similar to pumice. Originates from Japan (Kanuma) and is widely used |

| |there when growing Bonsai. Not readily available - refer to scoria. |

|“Kitty Litter” or “Cat Litter” |Either Bentonite clay for “clumping” cat litter or zeolite, diatomite and sepiolite for |

| |non-clumping cat litter. The use of non-clumping kitty litter may be useful but I would |

| |not recommend the “clear” or “crystal” kitty litter as a potting mix component. |

|“Loam” |Sand, silt and clay with organic matter. Loam can be used as a component of your potting |

| |mix but is too fine by itself and is not free draining enough. |

|“Pea Gravel” |An aggregate of crushed rock that could be composed of granite, dolomite, limestone and |

| |other rocks, crushed and screened to a size around that of a Pea. |

|“Shale” |A sedimentary rock composed of clay or mud that is easily broken into plates. |

|“Zeoclor” |A commercial product of Zeolite – see Zeolite - usually sold as a swimming pool filter |

| |material. |

|Beach Sand |Silicon (silicon dioxide) in the form of quartz. Not recommended as it is too fine and |

| |there may be difficulty in removing all the salts. |

|Charcoal |A form of carbon, usually from wood heated in the absence of air. Used in many potting |

| |mixes and can help to “sweeten” a potting mix by absorbing excess salts. Commonly used in|

| |orchid potting mixes in high volume. |

|Course Sand |Usually washed river sand, graded to sizes around 1 to 2mm. Whilst usually sold as |

| |“course”, the size is mostly too small to be used as the only inorganic component in your|

| |mix. |

|Crushed Red Brick |Crushed red house bricks. Bricks are normally made from clay bearing soil, sand and often|

| |lime that has been kiln fired but can also be made from concrete. Whilst clay bricks are |

| |fine, those made from concrete are of no use. Recycled red brick is generally around 1 to|

| |3mm in size. |

|Crushed White Quartz |White quartz aggregate. Works well in a mix but can turn green on the surface of your |

| |mix. A different “topping stone” around the plant will stop this from happening. Widely |

| |available and is often used in landscaping and around grave sites for decoration. |

|Decomposed Granite |Naturally weathered granite, a hard igneous rock. Equally as good as scoria, is generally|

| |available everywhere and quite cheap. Used in sizes 1 to 6mm. Combined with scoria at |

| |2mm, I use decomposed granite 1 to 3mm for starting all my seeds. |

|Fired Clay Chips |Fragments of clay that has been fired in a kiln. Broken terracotta pots could be |

| |described as “fired clay chips”. I have never used this material but given that it is |

| |hardened/fired clay it should be fine. |

|Lava Rock |Volcanic rock, usually basalt and high in iron content (see also Scoria, Perlite, |

| |Zeolite, Pumice) Whilst I use scoria because of the availability, Zeolite and Pumice are |

| |both as good but may be priced at a premium compared to scoria. Zeolite in particular |

| |varies in quality and the Australian Zeolite is the highest quality but may not be |

| |available in countries other than Australia. |

|Perlite |Hydrated obsidian, heated to around 1300C to cause it to expand approximately 13 times |

| |its unheated size. Available in various sizes with 3 to 4mm being the ideal size. |

| |Although this material works fine, albeit with holding more water than most inorganic |

| |materials, I no longer use Perlite in my mix as it is very light, can rise to the surface|

| |when watering and floats all around the nursery making a mess. |

|Pumice |A lightweight volcanic rock. Because of the cost, I have not used Pumice. However, it is |

| |used worldwide and can be used as a pure mineral potting substrate, as can nearly all |

| |materials derived from volcanic rock. |

|Scoria |Dark volcanic rock, usually called “red” or black” scoria, basic properties include |

| |Basalt and is high in iron. “Red” or “Black” scoria is long lasting and "red" scoria is |

| |used in my potting mix. I find that "red" scoria has more surface area than "black" |

| |scoria due to many fine holes and indentations in the surface. |

|Shells |Calcium carbonate. Not recommended as this can break down too quickly. |

|Turface |Fired calcined clay. Not available where I live but as a component in your potting mix, |

| |it should be fine. |

|Vermiculite |Hydrated aluminium-iron magnesium silicate, expanded by heating. Resembles Mica. Not |

| |recommended as this material holds far too much water. |

|Zeolite |Calcium, potassium, magnesium, aluminosilicate formed from volcanic ash. Not all Zeolite |

| |is the same; Australian Zeolite is approximately 300 million years old and is the best in|

| |the world. |

|ORGANIC |NOTES |

|Commercial Potting Mix |See also “Cactus Mix” – commercial potting mix may contain pumice, sand (course and |

| |'horticultural'), scoria, bark, compost, humus, earthworm castings, mushroom compost, |

| |perlite, charcoal, vermiculite, peat, wetting agents and ‘recycled green waste’ as well |

| |as fertiliser. A “standard” general purpose potting mix usually does not contain much, if|

| |any, fertiliser whereas a “premium” potting mix will contain added fertiliser and trace |

| |elements. As an organic component of your potting mix, standard potting mix contains all |

| |the organic material you need although it should be sifted through a sieve with an |

| |aperture of 5mm to remove all larger pieces of bark. Try to avoid commercial potting mix |

| |that contains “mushroom compost” and “peat” as neither of these materials are |

| |particularly good. Some standard potting mixes contain large amounts of wood shavings or |

| |chips and little else and should not be used. Those are usually the "cheap" brands. I use|

| |a standard potting mix, sifted to remove anything larger than 5mm, as the organic |

| |component in my mix. |

|“Cactus Mix” |Commercially available potting mix made for potting cactus (and succulents) – commercial|

| |“cactus mix” may contain pumice, sand (course and 'horticultural'), compost, humus, |

| |earthworm castings, mushroom compost, perlite, charcoal, vermiculite, peat and ‘recycled |

| |green waste’. All commercial “cactus mix” is mixed to be free draining, but not all are |

| |created equally. As an organic component of your potting mix, “cactus and succulent” mix |

| |contains all the organic material you need although it should be sifted through a sieve |

| |with an aperture of 5mm to remove all larger pieces of bark. Generally, "cactus and |

| |succulent potting mix" does not contain excess amounts of wood shaving or chips. |

|Bark Chips/Fines |Usually Pine bark, mostly aged or weathered and screened. May be available in other |

| |timbers, for example Fir. |

|Leaf Mould |Slowly decomposed leaves and often other green material. |

|“Coir” or “Coconut Fibre” |The fibre from the outside of a coconut. |

|“Compost” |Recycled organic materials decomposed in a process called composting. |

|Peat Moss or Peat |An accumulation of decayed sphagnum moss which occurs in “pet bogs”. Not recommended as |

| |the organic component of your mix although this, combined with Perlite, is often used by |

| |commercial nurseries which enables very fast growth which is not good for growing |

| |Mesembryanthemum. Commercial nurseries also use a very controlled environment, something |

| |generally not available to other growers. |

|“Mushroom Compost” |A spent mix that has been used for the propagation of mushrooms, usually composed mainly |

| |of peat. Not recommended as the organic component of your mix as it encourages the growth|

| |of fungus. |

Like organic material, inorganic material should be sifted to remove any pieces over 8mm when used as, or in, a potting mix for Lithops. When using a pure inorganic material for starting seed, it is best to use material in a size range of 0.5mm to 3mm. If too much very fine material is used, the mix can clog or become very hard making it difficult for the germinating seed roots to penetrate. Similarly, if the mix is all larger pieces the seeds may end up being washed further into the mix than ideal and may also dry too quickly.

4. Lighting.

One of the questions that often gets asked is “Can I grow my Lithops in full sun?” Seeing Lithops in their natural habitat tells me that although Lithops appear to grow in full sun, that isn’t really the case. Lithops enjoy shade to some extent from surrounding grasses, shrubs and rocks, even if they are exposed to “full sun” at some point during the day. For the purpose of cultivation, shade of around 50% is ideal but plants can be “acclimatised” to higher light levels if there is good air flow.

When it comes to artificial lighting, there are many different answers. Apart from “T5” fluorescent lights, there are compact fluorescent lights, LED (Light Emitting Diode) lights, halogen, ceramic and metal halide discharge lights and others. As with potting mixes, not all are created equal and factors such as heat from the light and distance above the plants and of course quality and makeup will affect how well they work. I do not use artificial lighting except for starting seedlings in winter and they are used in conjunction with heat cables.

Other than the light intensity (Lux, Lumens, Candela, Flux, Watts) Lithops need, there also needs to be consideration for the time exposed to the light. I have never done complex calculations on the intensity of the light my plants receive under 50% shade however it is acknowledged by several “experts” that plants require around 13 hours light to flower properly.

5. Watering.

Watering Lithops is probably the hardest thing to learn. I have seen advice like “give it a teaspoon of water” and “don’t water until it is shrivelling” on forums and I wonder if the person giving the advice knows all the facts about the plant in question! The same sort of advice appears when people ask “when to water” and again, there is little other information being offered as to what the person is using in their mix, what season it is or what the weather is like.

There are two different regimes for watering cultivated adult plants versus seedlings. Seedlings in cultivation can take, and require, more water than adult plants in cultivation, even if this may not be the case in their natural habitat. Seedlings should be watered more often than adults until they are around 12 months old at which time they will fall into the annual cycle of adult plants. For the first three or four months, tiny seedlings should be misted lightly and not be allowed to dry out for more than a day or two. After that, watering should be tapered off until the plants are around 12 months old at which time they should be treated as old plants, following their annual growth cycle.

Whilst watering seedlings in this manner sounds straight forward, you should remember that it also depends on when you started the seed. For example, starting seed at the end of autumn (fall) under artificial lighting and using heat mats would enable you to water more regularly and for longer than three or four months as the seedlings would still be very young when spring and then summer arrives. I start seedlings at all times of the year but find the end of Autumn(Fall)/beginning of Winter gives the best results when using artificial lighting. The beginning of spring gives good results when starting seeds in the nursery under natural light and without heat mats.

There is a fair amount of confusion regarding watering adult plants and also the term “dormancy”. Looking at the annual growth cycle of adults’ plants, there is reason to think that plants are “dormant” in Summer but in reality they are simply guarding against transpiration. While the plants do not need copious amounts of water in summer, this is the time when it rains in their natural habitat. Remember of course that it is generally cooler and darker when it rains so it makes sense to water only when you have a cooler or overcast day. I water only in the early morning on cooler days, when the plants have been dry for at least a week and over Summer this may only happen once of twice. Plants that are shrivelling badly (lots of wrinkles on the sides of the body) should be watered, even if only lightly, and they will plump back up within a matter of a day or two. Watering in the heat of the day in summer can very easily turn your Lithops into a pot of soup!

The main two seasons to water in spring and autumn. In spring, after the old leaves have turned to paper husks, the new plant leaves will benefit from watering and prepare the plant to be in the best condition for upcoming flowering, mostly in late summer and early autumn. In autumn, watering will ensure that the set seed pods get the best chance to produce the best seed. Once winter arrives, no water should be given at all.

You may also hear that Lithops are “dormant” in winter and whilst this is true to a certain extent, the plant is not really resting. Deep inside the plant, a new set or sets of leaves are beginning to grow. The old leaves are “used” to provide moisture and nutrients to the new leaves and any water given at this time of the year can do one of two things. (1) The plant will rot overnight or (2) the old leaves will not be absorbed but remain on the plant. This is called “stacking” and whilst it may not damage the plant, it is not desirable and may lead to rot later.

6. Starting Seeds.

Although there are other methods of starting a Lithops collection, growing from seed is by far the least expensive and the most rewarding. Some species/subspecies/varieties can be much more difficult than others but a “mixed” lot of seed will give you an excellent start with very little disappointment. “Cultivars” are generally more difficult to grow than sp/ssp/v too. Apart from seeds, divisions of mature plants and adult plants will give you instant results however they are much more expensive and often very difficult to obtain.

If you are using artificial lighting and heat mats, you can start Lithops seeds at any time of the year however I find that early autumn gives the best results. Early spring is also a good time but I do not have the same success rate at this time of the year, especially when starting seeds under natural light.

Germinating Lithops seeds (and most cacti/succulents) has the basic requirements of high temperatures and humidity. “High” temperature for germinating Lithops is in the range of 20 to 23C daytime and 14 to 16C night time. A drop in temperature overnight, rather than a constant temperature, seems to assist in germination. Achieving high humidity is a simple matter of providing a closed environment and a little further on you will find some options that have worked well for me.

The size of the pot used to start seeds should be large enough to accommodate the number of seeds you are planting but not overly large so that when germinated the young seedlings are very sparse. Seedlings tend to do better when they are slightly crowded. As an example, a 55mm pot is used to plant approximately 20 seeds and a 63mm pot is used to plant 40 seeds.

The mix used for starting seedlings can be the same as used to pot adult plants however far less organic material is required and the size of material needs to be smaller. Sifting the mix used for adults through an appropriate sized sieve is possible. The use of straight inorganic material is preferred and the size of the material should be 0.5 to 3mm. The use of straight inorganic material does mean that at some point the young seedlings will need to be fed. If a regular “garden fertiliser” is used, it should be mixed at a rate ¼ of that recommended for garden plants or ½ of what is recommended for orchids. You should always read the mixing rates on the packet/bottle and calculate from there.

Another good product for young seedlings is seaweed extract, again at ½ the recommended dose for orchids. Here in Australia, there is a product called “Seasol”® and this is what I use, once when the seedlings are around 4 weeks old, again at three months and then at 12 months which is normally just before they are potted individually.

There are a few methods of providing the warmth and humidity needed for growing all cactus and succulent seeds and the one I use may not be as successful for you as it is for me. One method is called the “baggy method” which involves the use of "zip lock" bags to create humidity. Simply fill your chosen pot to about 10mm from the rim, wet the mix thoroughly and then sterilise it by either pouring boiling water through the pot or by placing it in a microwave and “cooking” the whole lot until it is hot. I use a microwave and “cook” 30 x 55mm pots on high for 15 minutes.

As a matter of interest, I DO NOT recommend the use of "paper towel" nor "cotton" as a substrate for starting seeds on as when you come to potting up your seedlings you will have great difficulty. Likewise, Petri dishes should be confined to the laboratory, not the nursery!

An alternative to using the “baggy method” is to use take away containers (with a few holes in the bottom) or “mini green houses” that are sold at most garden centres and some hardware stores for starting vegetable seedlings. These come with a clear lid and can accommodate 30 x 55mm pots at a pinch and 15 x 63mm square pots. These are what I use and I find them very good plus they are easy to keep warm using reptile warmer cables placed underneath them. A few “pot feet” will hold the mini green house above the cable. Bear in mind that the use of a heat cable also necessitates the use of a thermostat to control the temperature.

Once your sterilised pot of mix has cooled, make sure the substrate is well watered and then all that is needed is to sprinkle the tiny seeds over the surface of the mix and then mist them in. A hair spray bottle works well for this. Lithops seeds are coated with substance that when wet acts a bit like glue and they will adhere to the particles of mix. You don’t need to actually wash them into the mix, even though some will be deeper than others, as they will germinate and send roots down into the mix.

To help plant the tiny seeds more evenly, you can mix the seed with fine, dry sand and then sprinkle this on the surface. Folding a small piece of paper in half to give a crease will also allow you to see the seeds better and also control them as you sprinkle them.

Seeds will germinate anywhere from 3 days to over a period of about 6 weeks, depending on how good your conditions are and also how fresh the seed is. Older seed, 12 months or more, will germinate all around the same time whereas fresh seed germinates more sporadically over a longer period. Your tiny seedlings may become “tall” or “leggy” if you do not provide sufficient light. A very light sprinkle of around 1mm sized inorganic material will help to prop up any seedlings that are falling over.

Once you are happy with the germination rate, open the vents on the mini green houses or slightly open the zip lock bag. Continue to open the zip lock bag over a period of a week until it is fully open at which time you can remove the pot from the bag. With the mini green houses, you can fully open the vent and leave them that way whilst the seedlings continue to grow over the next few weeks. In both cases, the mix should start to dry out and when the top of the mix is dry, mist it lightly to dampen it again. Once it has dried again, repeat the process.

When the seedlings are a month old, you can apply a weak solution of seaweed extract or fertiliser, even if you are growing in a mix containing organic matter. Do this again at three months and then at 12 months, just before you pot the seedlings into individual pots. Although seaweed extract is not considered a “fertiliser”, I find it helps both in growth and also plant health, enabling the young seedlings to resist damping off better. Continue to mist the seedlings as the top of the mix dries out for the next three months but it is time to allow the seedlings to dry out for longer between misting them. If the pot becomes fully dried out, simply water (still misting) the seedlings until they are again thoroughly wet.

At around 12 months your seedlings should be big enough to handle and can now be potted up individually. Do expect some losses at this small size and if you are happy enough to leave them in the pot you started them in for longer, do so and only repot when you want to or the seedlings are pushing themselves out of the pot!

Your “seedlings” are now well on their way to becoming adults and should be treated as such from now on. This means watering them only once they are completely dry. You should start to follow the growth cycle for Lithops from now on. (See the table above)

Lithops are considered “adults” when they flower and this is 2 to 3 years for most species but some take 4 to 5 years before they first flower.

7. Observations.

Here are a few observations made from growing Lithops from seed for what seems like the last millennium, even though it has only been the past two decades or so!

• Some Lithops species tend to grow more than one set of new leaves more easily than others. Lithops verruculosa is one of those. If a plant grows two sets of new leaves in lieu of the usual one, the two new leaf pairs will be notably smaller than if there was only one new leaf pair.

• Different species flower at different times. Often, pseudotruncatella is the first to flower in early summer and the optica are last to flower, well after the other have finished and as long as three to four months later. Optica, especially ‘Rubra’, also like to be watered lightly and more often than all other Lithops, most likely because their natural habitat is coastal where they receive sea mist and fog instead of heavy rain.

• Various species are easier to grow than other and some can be quite difficult in comparison. Easy species include aucampiae, lesliei, hookeri and gesinae. Difficult species include comptonii (variety weberi especially), divergens, viridis, herrei, geyeri and optica. The others fall somewhere in between but one grower finds difficult may not be so for another grower!

• Seedlings that are tall (“leggy”) are not receiving enough light and will tend to fall over and/succumb to rot. A little course sand/scoria/pumice can be lightly sprinkled around to help prop them up.

• Insect pests are few and far between with Lithops. The most common issue is with mealy bug (in amongst the roots of a plant, this is also referred to as “root mealy bug”). This pest is best dealt with by the use of Imidicloprid, if it is available. Metholated Spirits on a cotton bud can be used to wipe off visible mealy bug but should be washed off immediately after use to stop burning of the plant.

• Cultivars, in general, are more difficult than most species although those bred from the easier growing species are obviously easier to grow. Cultivars are always more expensive to buy than species and a lot are very difficult (and sometimes literally impossible) to buy.

• Too much water will cause the following symptoms: Death overnight with a resultant pot of Lithops soup, leaf stacking, flowers erupting through the side of the body and bodies being pushed up from the base from the new leaf pair growing rapidly without absorbing the old leaves.

• The “cleft” or “split” between the two leaves can give a good indication of a species. Pseudotruncatella has a tiny cleft until the plant is around two years old. Divergens and meyeri have a deep cleft that extends almost to the base of the plant and the leaves themselves are “longer” rather than rounded and flat-ish like other Lithops.

• Plants will sometimes grow three “leaves” instead of the normal two. This generally only last one or two seasons before the plant returns to normal.

• “Monstrose” Lithops are very rare but do occur now and then. The same thing happens as plants with three leaves, they generally return to normal growth after one or two seasons.

• Lithops are “self-sterile” – They require a separate clone to successfully pollinate. However, they can be tricked into self pollination by firstly applying the pollen from another genus, Lapidaria for example, and then applying the plants own pollen. Lithops will sometimes set seed using only the same plants pollen however there are generally very few seed produced and those that are, are often weak.

8. The Last Word.

As stated at the beginning of this guide, this is just that, a “guide”. What works for someone else may not work for you as there are so many variables to take into account that it is impossible for anyone to tell you exactly how to start and grow Lithops or other Mesembryanthemum. What this guide intends to show you is that with a little patience, some suitable materials and somewhere to grow Lithops, you should have success.

I do not consider myself an “expert” and even those who are considered to be experts in this field will only give you advice and no guarantees. There is a lot of information on the Internet and advice in forums can be confusing and conflicting, depending on the source. In any forum, you should do yourself a favour and search the forum for the information you are looking for and also check the “files” section before asking for advice. If you can’t find what you are looking for, ask a question and you should expect a respectful reply.

For a better understanding of Lithops, buy yourself a book and/or join a cactus and succulent society. The two books I recommend are:

• “Lithops – Flowering Stones” by Desmond T. Cole and Naureen A. Cole ISBN88-900511-7-5

• “Lithops – Treasures Of The Veld” by Steven A. Hammer ISBN 0 902 099 92 2.

The Cole book is difficult to obtain and now quite expensive but is a wealth of information and regarded by “Lithopsarians” as the best. The Hammer book is fairly priced and still readily available, even though the second publication was 2010.

If it is cultivars that really interest you, there is only one authority on the subject. Keith Green is the International Registrar for Cultivated Lithops and his website is – I am the Standby Registrar and wrote the website for Keith back in 2012 but my knowledge of cultivars and the detail within is Keith’s area of expertise.

Thank you for taking the time to read this guide and I hope you have great success. Over the past few decades, Lithops have given me great pleasure and will continue to do so until I am no longer physically able to care for my plants. Yes, my plants will outlive me and probably you also if they are cared for correctly as they have an estimated longevity of at least 70 years.

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