For watering a basic rule: it is very difficult to kill a Lithops thirsty but very easy to kill him with excess water. However, contrary to what is often read, the water requirements of Lithops are very variable depending on the species, both in terms of quantity and season or watering mode.
Although accurate weather data is provided on the “locate” tab, a golden rule is regular plant observation. From April to October, as soon as the plant begins to wrinkle you can water and wait until it is wrinkled again to water newly. In winter no real watering but spraying is recommended on the species of southwestern South Africa (comptonii, divergens, marmorata, naureeniae, otzeniana, terricolor, villetii, viridis) and the west coast of Namibia ( ruschiorum, optica, francisci, helmutii, hermetica, herrei, geyeri, meyeri) to simulate winter rains or coastal mists.
For those wishing to refine their watering, the following images illustrate the thermal conditions (winter minimum and summer maximum) [in red figures] and rainfall (monthly distribution of rain and mists) [water drops or spraying] for the 37 species of Lithops. When significant differences exist within the same species or between a species and one of its varieties, the most representative conditions are illustrated.
Pay attention that the months indicated correspond to the northern hemisphere to allow the transposition of these data in a watering calendar.
Lithops amicorum : cold desertic climate.
Lithops aucampiae : semi-arid with cold winter climate.
Up the type with a drier climate (Griquatown), middle Kuruman form with a rainier climate (Kuruman) and down koelemanii variety with a warmer winter (Postmasburg).
Lithops bromfieldii : semi-arid with cold winter climate.
The type and insularis and mennellii varieties fit with a dry pring (Upington) while glaudinae variety prefers more rainy spring and summer (Griquatown).
Lithops coleorum : semi-arid with template winter climate.
Lithops comptonii : Mediterranean semi-arid or humid climate.
Big rainfall differences between the type with a lot of rain from October to March (Ceres) and weberi variety with low rainfall during fall and winter (Calvinia).
Lithops dinteri : hot desertic climate.
The type, variety brevis and sub-species multipunctata grow under dry conditions (Warmbad), while sub-species frederici prefers low rainfalls but from April to October (Pofadder).
Lithops divergens : hot desertic or with cold winter climate.
The type fits with the drier and hotter conditions (Vanrhynsdorp), while amethystina variety is adapted to lower temperatures (Loerisfontein). Take care that rainfall occurs during fall and winter.
Lithops dorotheae : hot desertic climate.
Lithops francisci : desertic with template summer climate.
Lithops fulviceps : hot desertic or with cold winter climate.
laevigata variety fits with low rainfall from april to october (Pofadder). All the others fit with summer and fall rainfalls (Karasburg or Upington), but lactinea variety requires warmer winter temperatures (Keetmanshoop).
Lithops gesinae : hot or cold desertic climate.
The type (Maltahöhe) fits with lower rainfal and temperatures than annae variety (Helmeringhausen).
Lithops geyeri : desertic with template winter climate.
Lithops gracilidelineata : hot or with template summer climate.
The type and brandbergensis sub-species fit with low rainfall in summer and beginning of fall (Usakos) while waldroniae variety contents with the air moisture brought by coastal fogs (Swakopmund).
Lithops hallii : desertic or semi-arid with cold winter climate.
The type grows under rainfalls ranging from 240 mm (Prieska) to 320 mm (Hopetown) distributed from April to October with negative winter temperatures, while ochracea variety grows under drier but less cold conditions (Upington).
Lithops helmutii : hot desertic climate.
Lithops hermetica : desertic with template summer climate.
Lithops herrei : desertic with template summer climate.
Lithops hookeri : desertic or semi-arid with cold winter climate.
The type grows under rainfalls ranging from 200 mm concentrated from june to september (Marydale) up to 300 mm spread from April to October (Strydenburg); dabneri variety grows in the less cold and more wet biotopes (Kimberley); elephina et marginata varieties withstand colder winters with rainfalls ranging from 250 mm (Britstown) up to 350 mm (Hopetown); lutea and subfenestrata varieties grow in drier conditions but with similar temperatures (Groblershoop and Prieska); susannae variety occupies an intermediate situation (Douglas).
Lithops julii : hot or with cold winter desertic climate.
The type and rouxii variety grow in the hotest biotopes with low rainfalls at the end of summer and the beginning of fall (Warmbad); fulleri sub-species and brunnea variety cover a larger gradient with fresher winters (Kenhardt) and lower rainfalls which extend from spring to fall (Pofadder).
Lithops karasmontana : desertic climate.
This species grows under very arid conditions, and a wide range of thermic regimes : the type withstands hot temperatures in summer and low temperatures in winter (Grünau), bella sub-species template temperatures in summer and low temperatures in winter, and eberlanzii sub-species template temperatures in summer but mild winters (Lüderitz).
Lithops lesliei : semi-arid with cold winter climate or subtropical climate.
This species cover a wide range of climates from semi-arid with cold (Warrenton) or template winter (Pietersburg) to subtropical humid (Johannesburg) or with cold winter (Harrismith).
The type and hornii, minor et rubrobrunnea varieties withstand abundant rainfall from March to December with cold (Pietersburg) or very cold (Harrismith) winter temperatures. Sub-species burchellii is restricted to the driest zones with less than 350 mm (Douglas) while mariae and venteri varieties occupy an intermediate situation with rainfalls around 450 mm (Warrenton).
Lithops marmorata : hot desertic climate.
The type fits with low winter rainfall (Steinkopf) while elisae variety benefits from fog moisture during the end of fall and winter (Vioolsdrif).
Lithops meyeri : desertic with template summer climate.
Lithops naureeniae : hot desertic climate.
Lithops olivacea : hot desertic climate.
Lithops optica : desertic with template summer climate.
This species benefits exclusively from frog moisture during fall and winter. It is the less resistant to cold.
Lithops otzeniana : desertic with cold winter climate.
Lithops peusotruncatella : semiarid with template climate or cold desertic climate.
The type and dendritica, groendrayensis and volkii sub-species prefer the wetest biotopes (Windhoek) while archerae sub-species fits with rainfall concentrated from end of summer and beginning of fall (Maltahöhe).
Lithops ruschiorum : desertic with template winter climate.
Up lineata variety (Cape Cross), down the type (Swakopmund).
Lithops salicola : semiarid with cold winter climate.
The species fits with low but regular rainfall from April to November and withstands negative winter temperatures.
Lithops schwantesii : hot or cold desertic climate.
The type and rugosa variety grow in the hotest and wetest areas (Helmeringhausen), marthae and urikosensis varieties in fresher and more arid environments (Aus), while gebseri sub-species occupies an intermediate situation (Maltahöhe).
Lithops terricolor : cold desertic climate or semiarid with template winter climate.
The species occupies a wide range with varied climatic conditions. In the northern part (between Beaufort West and Aberdeen) it benefits from low but regular rainfall from April to November as well as in the soutwestern part (Steytlerville). In the southern and southeastern areas it withstands much more cold and dry conditions (Prince Albert and Laingsburg).
Lithops vallis-mariae : hot or with cold winter desertic climate.
The species covers a wide triangular area, colder in winter and more wet towards the north (Mariental) but drier and with more mild winters southeast (Berseba).
Lithops verruculosa : desertic with cold winter climate.
Lithops villetii : hot desertic climate.
The type (Loerisfontein) and deboeri variety (Gamoep) benefit from rainfall extending from fall to winter, while kennedyi variety fits with rainfalls ranging from April to October (Pofadder).
Lithops viridis : desertic with cold winter climate.
Lithops werneri : hot desertic climate.
