I live in Belgium, a small country with mostly wet summers and cool winters. My Mammillaria are kept in a greenhouse (6x3 meter). They are placed in a sunny spot where they get strong sunlight; more than 10 hours a day in summer. During winter nights, I keep the temperature at 8�C with an electric heater.
My Mammillaria grow best in black plastic pots that should have a few drainage holes in the base. Black pots absorb the warmth more easily in our Northern European climate. This kind of pot allows good drainage and allows the soil to breath.
My Mammillaria prefer an open and very well decomposed leaf mould which should consist of: 3 parts regular soil from the supermarket, 1 part lava rock, 1 part crushed pumice (we call it bimskies), and 1 part loam. I keep my plants almost completely dry during the winter months, I only water the grafted ones to prevent them from completely drying out; once a month a few drops should be enough. Starting at the end of March I begin to watering sparingly. I water this kind of cacti at least once every 2 weeks during the summer. Starting in late September I reduce watering to force the plant to go into a state of semi dormancy. In October, the plants receive the last drops of water.
I repot every other year; annual potting is not necessary. I remove the plant from its pot, and remove the old soil to examine the roots for any damage or signs of rotting, I remove the soil as close to the plant as possible. In case of presence of rotten roots, I cut off all the roots and let the plants dry for a week before repotting it in �bimskies� to get new roots.
For disease prevention I use SILPAN once a year for red spider mites and TELETOX 40 for mealy bugs. These are two excellent products. Also, two times a year, I give them a fertilizer.
These are the method and conditions, where I keep my Mammillaria in. I have good results with it. However, please remember that each grower will need to find the best growing methods for his or her conditions.
Greenhouse in wintertime
Seedlings of mam senilis
I live in Southern Arizona, which in many ways is the best place to go cacti. But our climate does present some special challenges. While it doesn�t get extremely cold � this winter had a low of �7C, my plants were only exposed to �3.3C. However, in the summer, I have seen temperatures reach 48.8C! That is a huge range of temperature for these small plants to endure. Fortunately, the humidity is rarely more than 20%.
Very few Mammillaria can withstand the hot sun of a midday summer day. Therefore, I grow my plants in shaded benches, which provide some shade in the summer, and cover in the winter.
I allow my most tender plants to go down to about 4.4C degrees, and the hardiest species are allowed to go down to �5C. Because I stop watering in October, the plants are nicely hardened off for these cold temperatures. If I did water all year, most would be damaged or lost by the cold.
Most local growers have their plants in plastic pots; I am the rare exception. I use clay or terracotta exclusively. Besides the esthetic appeal of clay over plastic, there are a few important benefits to clay pots. Most important is that clay allows water to evaporate through the sides of the pot, and that cools the pot. Also, I think that I have superior root development with clay pots.
Mammillaria can benefit greatly from a fertilizing program. I fertilize at � strength once each month starting in April, after the plants start their spring growth. Fertilizing is continued through August, and then stopped, as they need to start hardening for the coming cold weather. The fertilizer used is 15:30:15 (N:P:K) with trace elements of Boron, Copper, Iron, Manganese and others. It is a water soluable granular material that is mixed in a watering can before application.
The potting mix is very open and porous. It consists of pumice, large particle sand, peat, and loam. It must be mixed in proportions that will allow water to flow freely through the mix�in fact hopefully it is pouring out of the bottom of the pot just as I finish filling the pot. Watering frequencies vary with the weather, the species, and the size of the pot.
My method of determining if water is needed is to lift the pot�with a little experience, one can tell when the pot has dried out completely�that�s the time to water again!
Please remember that your growing techniques will be your own. Base them on the plant�s location, and the variables listed above. Everyone with time develops their own techniques; as you continue to gain experience, you will develop your own techniques. However, I hope that my experiences and other grower�s experiences will be a helpful guide. And remember, there are many people ready to help you, so ask questions! Especially use the forums on mammillarias.net.
One of Norm's growing benches
2.Grafting on which stock?
3.Grafting in practice
Most Mammillaria in our collections don't need to be grafted at all. But it may happen that one of our plants is rotting. In that case, the plant might be rescued by being grafted. If the bottom of the plant is rotting, cut off the rotting part. There must no yellow coloured part of the plant be left. As soon as this is done, the plant is to be grafted at once.
Another reason for grafting is to multiply rare plants or to accelerate flowering of a slow growing plant. The very difficult Mammillaria tetrancistra can hardly be cultivated without being grafted.
2.Grafting on which stock?
These species of cacti are recommended: Trichocereus spachianus, T. pachanoi, T. schickendantzii, T. macrogonus, Eriocereus jusbertii , echinopsis species, Pereskiopsis, Myrtillocactus geometrizans and Opuntia pads.
3. Grafting in practice
The most important step is to carefully prepare the graft and the stock so that the saps of either part can rapidly circulate smoothly through both. The sap of the stock must be able to circulate freely through the graft. Both, graft and stock are to be at full growing force at the time the grafting is done. Required outfit is: a knife, elastic bands, a clean fabric and a new razor blade. Another important point is that everything must be absolutely clean. After each cut, the knife must be cleaned again, in order to not propagate any disease. If the graft is a small seedling, use a new razor blade. As a first example, let's use the grafting on an Echinopsis hybrid or related species. A not too large part of the head is cut off. Once you see a small circle, it's the right height. From the remaining stock, the sides of the top are oblinquely cut off. A further small slice is cut from the top and left, for the moment, lying on it to avoid drying the cut surface. Then comes the graft itself: the bottom part is cut off, just above the collar. With one hand, take off the slice left on the stock and with the other hand place the graft in the middle of the cut surface of the Echinopsis, on the edge of the circle. Very small seedlings can be successfully grafted on Pereskiopsis. Here too, it is important that both stock and graft are in full growth. From the Pereskiopsis, the upper centimeters are horizontally cut off. The seedling is cut as a graft and placed on the middle of the stock with a slight push. When grafting on Pereskiopsis there is no need to use additional means to press the two parts together. On Echinopsis, a light pressure can be maintained by placing two elastic bands in a crossing pattern over the graft and under the bottom of the pot in order to hold the graft in its place. After a few days, the bands can be carefully taken off, the grafting operation ought to have been successful. The big advantage of Pereskiopsis is the fast growth of seedlings and a graft stock that can be rapidly multiplied. Grafting is done preferably during warm dry weather. That means from April until September. Once grafted, the plants are put in a shady place and kept somewhat moistened. If you are not successful the first time, do not despair and keep trying.
Mammillaria nivosa seedling grafted on pereskiopsis
Just like our friend Hugo, I live in Belgium. My collection is cultivated in a greenhouse of 3.60 x 2.50 m, complemented by two mini-greenhouses of 120 x 50 cm and a covered bench of 1 x 4 m. Each of these is placed in a way to assure enough direct sunlight to all of the plants. The collection's composition is 60% Mammillaria, 30% Gymnocalycium and 10% of all other genera. The soil I use is made of: 1 part earth, 1 part cocopeat, � part perlite and 3 parts chippings.
The quantity of chipping entering the mixture varies according to the species. As far as possible, I use square black pots in order to save place compared to round pots, and black ones in order to keep the warmth as much as possible. Also, for some large clumps, I use round pans.
Watering, only with rain water, is done in the trays, which assures a perfect capillary moistening without the plant bodies getting wet.I am most fascinated by the sowing of our spined friends. I can say that 70% of my collection comes from my own sowings.
First of all, the pots used for the sowing are washed in a disinfectant solution of Dethol (available in pharmacy). Then, I prepare the soil. First comes sifting of the earth and cocopeat to take out all pieces too big or too hard. The only difference with my usual soil is that I add one part more of chippings (tiny gravel).
For sowing, I use red pots of 5x5x4.5 cm (LxlxH) (photo) that are filled up to 0.5 cm from the upper side; the soil is slightly tamped with a piece of wood, the labels are placed and the seeds are put in, and again slightly tamped. As soon as the pots are ready, I place them in a tray containing boiled and cooled off rain water. Then I place the pots in a mini-greenhouse that is heated at about 28� C to during the day and that cools off for the night till about 18� C. For the germination period, attention should be paid that the soils remains moistened.
All this is placed under the shelves of the greenhouse where I also installed additional lighting that is switched on from 7 AM until 10 PM, i.e. for 15 hours. This space is finished with offset plates that are good refectors so that all the pots receive enough light and avoid as far as possible a loss of light. The seedlings remain in this mini-greenhouse for about three months, afterwards, they are placed in another unheated mini-greenhouse and I start ventilating them and getting them acquainted with the adult living conditions. A first potting on is done after about 6 months, but that can be done much laer as well. Sometimes, in case of lack of time, they are potted on for the first time only after one year.
Translated by Willy