Propagating cacti: using cuttings, offshoots & seeds
Cacti can be reproduced in three different ways. This article explains how the process of propagation works with cuttings, offshoots and seeds.
Cacti can be found in every household. With the right care the prickly plants will decorate your house or garden for a long time. The following three methods with detailed instructions will teach you how to expand your cactus family.
Propagating cacti via cuttings and offshoots
Depending on the cultivated cactus species, different types of cuttings or offshoots can be taken from the mother plant and grown as a new separate plant. On the one hand, Rhipsalidopsis can be reproduced easily with leaf cuttings and Rhipsalis can be propagated with head cuttings. On the other hand, most tall columnar cacti (Opuntia, Pereskia) as well as pad forming cacti can be multiplied well with offshoots.
List of tools and materials:
- A sharp and disinfected knife
- Matches or a lighter
- Aluminium foil
- Plastic pots
Instructions for the propagation of cuttings and offshoots
The months from April to August are the perfect period for the propagation of cacti. Mind the thorns, though! It is best to put on thick gloves to protect your hands from the prickly cuttings or offshoots or use tools such as tongs to work with cacti.
The next step is to light a candle and heat the knife wrapped in aluminium foil over the flame. If the foil turns black, the knife is ready to use and the cuttings or offshoots can be cut off. The following applies: head cuttings should be 10-15 cm long, whereas spherical cuttings should be larger than their diameter and as wide as possible. Leaf cuttings are cut in their original size from the mother plant.
After each cut, the knife (which is still hot) is pressed onto the cut. This stops the sap flow and prevents the “bleeding” of the plant. Before making another cut, the knife should be wrapped in the aluminium foil and reheated by the candle flame again.
Next, leave the cactus cuttings to dry out in the air for a few days. The small roots should form and then, the cuttings or offshoots can be potted. The pots are filled with low-nutrient cactus substrate and cuttings or offshoots are potted halfway into the soil. You should not water the plants during the first week. Subsequently, the substrate is kept only slightly moist with soft water. As soon as the cutting has rooted well, it is re-potted and cared for like an adult representative of its species.
Tip: Use a match as a support for any larger leaf cuttings. This stops the plants from falling over.
Reproducing cacti via seeds
Reproduction using cuttings and offshoots is much easier than reproduction via seeds. There are, however, many species that are difficult to root or produce sprouts. For example, the majority of ball shaped cacti are propagated by seeds. Some of the rarest species are also often only available in seed form.
Cactus seeds at home
Since propagation by seed is a sexual form of propagation, it means that at least two specimens of the same species or variety are required. If flowers are formed, they can be pollinated by hand or with a brush. In this way, the pollen is transferred. If there is a risk of cross-pollination by other specimens, the cacti should be isolated. The typical cactus fruits, which look like big fleshy berries, develop by autumn and carry the seeds. Mature fruits are picked and, if necessary, pricked to release the seeds. The seeds are thoroughly cleaned (fruit flesh residues inhibit germination) and placed on blotting paper to dry. The cactus seeds can be stored until the next planting date (ideally in April) in labelled paper bags or small, airtight containers.
Breaking dormancy of the cactus seeds
As the seeds of many species (e.g. Notocactus and Coryphanta) are subject to dormancy, they must be treated before sowing. The seeds should be soaked for 20 minutes in 3.0 percent hydrogen peroxide (available in pharmacies). Then, the hydrogen peroxide should be diluted with water by 50 percent and left to rest for 24 hours.
List of materials and tools:
- Quartz sand in 3 mm grain size
- Seed tray or small pots
- Hydrogen peroxide
- Propagator or a mini greenhouse
Pure mineral material such as perlite or pumice beads have proven to work wonderfully as sowing substrate. The seeds can develop well and the roots can grow gently thanks to the structure of these types of substrate. A cheap alternative is cat litter (without clumps!).
Tip: Sterilize the sowing substrate before use in the oven for 30 minutes at 150-180 degrees or for 10 minutes at 800 watts in the microwave.
Since the freshly germinated cacti are vulnerable, the seed bowl, the pots and the propagator should be meticulously cleaned before use.
The pot is filled with substrate and the seeds are distributed. But keep this in mind: some seeds require light to sprout, so they may be pressed on, but not into the substrate. A thin translucent layer of quartz sand is used as protection against mould. The pots with seeds are briefly placed in lukewarm water (not lime heavy). After the soil with seeds is soaked with water up to the uppermost layer, the pots are put into the propagator or the mini greenhouse.
Temperatures between 20 and 25° C are ideal and direct sunlight should be avoided. The greenhouse should be briefly ventilated daily until the first thorns form on the cacti. After that, the top part of the propagator or a greenhouse can be permanently removed. It is important to always water from below. In order to do this, place the pots with seeds into lukewarm rainwater or boiled tap water and wait until the substrate is soaked.
Depending on the species, germination starts within a few days up to several weeks. Cactus species that germinate well and relatively quick are for example Echinopsis, Rebutia or Mammillaria. Opuntia, on the other hand, have the reputation that their seeds take eternity to germinate.