The wart cactus is really one of the more uncomplicated cacti. It is even considered a real beginner cactus. But it is also useful for Mammillaria elongata to learn something about its natural environment – only then can you understand the cultivation instructions. Then the care tips get a meaningful background. This is the only way you have the chance to understand and not just stash information. The first step from beginner to expert.

The wart cactus in its natural environment

The wart cactus belongs to the cacti in the narrower sense (cactus family, subfamily Cactoideae, tribe Cacteae) and, like all plants from this subfamily, has completely reduced its leaves, mostly converted into thorns. As with all cacti, this minimalism is a reaction to environmental conditions. The entire tribe Cacteae is at home in the warm south of the American continent on mostly very dry terrain.

Mammillaria elongata grows in the Mexican states of Hidalgo, Guanajuato and Querétaro, central Mexico. Its environment consists of barren mountains and not very nutrient-rich soils that are used for agriculture or for grazing. Not a luxury for a plant. In contrast to pure desert cacti, however, the wart cactus had enough nutrients available during its developmental history to become Mammillaria “elongata”, the “extended” Mammillaria. It is one of the few Mammillaria whose growth habit shows a clear trend upwards, while most of its conspecifics grow into heaps, knobs or balls close to the ground.

The wart cactus in Mexico is spoiled with light and warmth. The sun shines there almost the whole day, almost every day (daily average in the home area of ​​the wart cactus 7.3 hours of sun, Germany 4.3). Day temperatures between 20 and 30 °C prevail there all year round, and at night the thermometer rarely falls below 10 °C.

In the homeland of the wart cactus, there is an average of 710 mm of precipitation per year. That’s not much less than our average 756mm. However, Hidalgo etc is exceptionally dry from October to May with only 2.3 days of rain per month, while from June to September it rains 3 out of 4 weeks.

Note: Here the rain falls more evenly, with a slight increase in summer.

So these are the conditions you want to replicate as best you can for the wart cactus in your home.

The best location

From the above, it is clear that the wart cactus should be given one of the lightest locations your home has to offer. He finds the light here rather depressing anyway. At least one east or west window, preferably a south window. But then the wart cactus needs some shade when the sun falls on it directly through the glass pane in the midday hours.

Because of the high light requirement, the wart cactus should be placed outside in summer, preferably in the direct sun, but in a slightly rain-protected place. It’s less about the fact that it doesn’t tolerate rain from above, this cactus is used to that. But in a planter, water can never drain as quickly as cactus roots would like. If the balcony is built-in rather than open air and the weather is wet and cold for more than a week, you should put the wart cactus in a dry place until the humidity on the balcony is normal again.

Mammillaria elongata forms densely packed cushions of cylindrical shoots, still not exactly tree-sized despite “urging upwards”. He can hardly manage more than a hand’s length, then he prefers to spread out, he can fill up to 30, 40 cm. In any case, it remains in absolutely room-suitable sizes. It also doesn’t need to be placed out of reach of tender fingers – because of its harmless thorns it is called “ladyfinger cactus” in England.

The wart cactus is usually very happy with the other conditions in the house. The room temperature/temperature on the balcony corresponds (almost) to what he is used to in terms of heat. He also likes an average humidity of around 50% in the living room. For cacti beginners: Normal cacti have no place in the bathroom or in a kitchen used for cooking. In the long run, they suffer greatly from the humid air.

Tip: Epiphytic tropical forest cacti such as Easter and Christmas cacti feel at home in such locations.

planter and substrate

If you want to free yourself from close observation of the humidity in the pot, you should keep the wart cactus in a clay pot. More precisely, in a clay bowl. It develops a fairly fine-fibrous and fairly sprawling root system, a bit more sprawling than the cactus body above ground. A drainage layer of gravel is placed in the pot. Along with the moisture-balancing clay wall, you’ve done a lot to ensure that your wart cactus never experiences an unwelcome root bath.

The substrate should also be made porous so that water can drain off easily. The wart cactus grows in soil and not in rock accumulations like many other cacti, but in a very poor soil with a low humus content. For him you can use cactus soil from the trade, usually a humus soil mixture with some sand. The wart cactus likes this soil even better if you mix in more coarse sand with a grain size of 2 to 3 mm, at least a quarter. For example quartz sand for aquariums, or any other non-toxic sand with a normal pH value.

You can also use lean garden soil as the basis for your mix, but please do not use normal potting soil. For cacti, this is usually enriched with too much nitrogen fertilizer. Which encourages the wart cactus to grow, but unnatural growth.

The irrigation

After hibernation, the wart cactus gets increasing amounts of water, by mid-May the pot should be moistened ready for growth. The wart cactus is now watered normally until September, whereby normal means moderately – only give in water when the potting soil has dried up.

You can use normal tap water. If this is very hard, you will have to repot the wart cactus at least every other year.

Mammillaria elongata düngen

In contrast to desert cacti, Mammillaria elongata knows soil, but soil with few nutrients. In the pot, it would eventually run out of nutrients if you didn’t provide more. When this is the case depends on “the mood” of your wart cactus. A normal growing wart cactus is content with a little fertilizer once a month per season.

Above all, it needs very little nitrogen, which is important for the growth of “average plants” and is therefore plentiful in normal complete fertilizer. So you need cactus fertilizer that is low in nitrogen, about 1 part nitrogen (N) to 2 parts phosphorus (P) and potassium (K). It is cheaper to use self-mixed fertilizer and flowering plant fertilizer, which sometimes has exactly this ratio.

Per season means in the main growing season from May to August. The first application of fertilizer should be given as soon as the wart cactus starts to grow. In fact, it starts to flower for the first time in spring. Sometimes a second bloom comes in the summer when the wart cactus is outdoors.


Mammillaria elongata usually needs to be repotted when its roots have completely penetrated the substrate. This is the case after two or three years, ideally at the end of the hibernation, when the substrate has not yet been watered. First prepare the new planter. The drainage layer can already be filled in and make the ready-mixed substrate + shovel readily accessible.

Carefully loosen the plant body from the pot and shake off as much soil as possible so that the roots can be closely inspected. All dried, rotted or otherwise dead parts are removed. Pest infestation is treated.

Now hold the wart cactus vertically in the prepared planter and fill in new substrate all around. Once the pot is filled, you should shake/stuck it a little so that the substrate settles, if necessary, something needs to be refilled. If you didn’t have to prune too much at the roots, you can water (a little) immediately. If new fine roots have to form first, you should wait a week or two before doing so.

If you water your wart cactus with tap water, you should repot it at least every other year, or even every year if the water in your area is very chalky. Then you increase the pH value a little with each watering until it rises to values ​​that your wart cactus no longer likes (if you want to measure: above 7.5 it becomes critical). If you put the cactus in new soil, it will sit in normal pH values ​​again, and you don’t always need a new plant pot, you can simply change the substrate.


When the outside temperatures drop to around 12 °C on average day and night, it is time for the wart cactus to move indoors. Depending on the region, this is the case in September/October.

Tip: You should make the move at temperatures where the wart cactus will move indoors without a major temperature shock, i.e. when it is pretty much as warm outside as inside.

Now the time begins when the wart cactus is only supplied with water to a very limited extent. Even before the move, you can gradually reduce the watering. In the winter quarters there is only enough water that the roots do not dry out completely.

The fertilizer application is already stopped in August. The winter quarters should be bright and have temperatures between 2 and 15 °C, Mammillaria elongata is not particularly choosy. 4 to 12°C is best for flower induction because the wart cactus really settles down under these conditions.

He can now enjoy this rest period for at least 4 months until he is prepared for the growing season with a light mist of water from the end of March and watered immediately afterwards (with increasing amounts of water). Before clearing out for the summer quarters, it may be necessary to get used to it again, slowly to the sunlight, e.g. B. with two-week shading (at midday).

varieties and species

Mammillaria elongata is one of the better known and more common cacti in the genus Mammillaria, which comes in two subspecies:

  • Mammillaria elongata subsp. elongata: The actual wart cactus, as described here
  • M. elongata subsp. echinaria, which, in contrast to the nominal form, has 2 or 3 dark central spines, but care remains the same

There are several cultivated forms of Mammillaria elongata:

  • Mammillaria elongata ‘Copper King’: Very decorative with copper-colored thorns
  • Mammillaria elongata ‘Cristata’, the Brain Cactus, because that’s what it looks like
  • M. elongata ‘Julio’: Normal shape, pretty pink flowers
  • M. elongata ‘mostruosa’: Slow growing, rare, almost thornless green “little knobs”


Mammillaria elongata is constantly producing offspring that you can cut off, root and plant in their own pot. It can also be grown from seed (even homegrown if you have a second Mammillaria to pollinate).

If it has flowered, it might even self-seed. Then (sometimes in the year of flowering) mini cacti appear in the planter. For prospective breeders: The tiny plants created in this way are not necessarily pure species. Pollination was uncontrolled, and cacti easily interbreed.

For cactus experts, Mammillaria elongata is not exactly one of the most exotic cacti, but it could decorate a large living room in a varied way all by itself. It is available in a number of different forms, which differ greatly in appearance. Hardly any maintenance, all forms of the wart cactus are quite undemanding and willing to grow and are even well suited for initial breeding attempts.

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