A Complete Guide to the Latest Cactus Propagation Methods

Cacti are native to the tropical regions of North and South America, the tropical mainland of Asia and some nearby islands, with some growing in forests. The four most commonly used propagation methods are cuttings, division, seed sowing and grafting. Let's take a look below!

Cactus Grafting Propagation

Grafting is a horticultural technique commonly used on cacti. Because the root systems of some cacti are extremely fragile, after long-term cultivation the roots gradually lose their original function and disappear, and the plant consequently loses its vitality. Grafting is the panacea that saves these cacti. In addition, uses such as speeding up a cactus's growth rate or keeping a plant affected by root rot growing after the diseased part has been cut away can also be achieved through grafting.

When grafting, the rootstock chosen - the triangular column cactus - is one type of these cacti. The method is to cut off the growing point of the triangular column and make a slanted cut on the ridge, then place the cactus whose root system has been removed in the center of the rootstock, and next secure the position with string or a weight. After 1-2 weeks, the string and weight can be removed.

Cactus Division Propagation

Many cacti can produce offsets. For example, globe-shaped cacti grow small offsets on the stem, while prickly pear cacti or segmented cacti all produce offsets. For these varieties, the growing point of the cactus must be cut off with a knife; after a period of cultivation, many small offsets will grow near the growing point. Once the offsets have grown to an appropriate size, they can be cut off for cutting propagation.

Cactus Seed Propagation

1. Hand pollination: Among cacti, few species are self-pollinating. Most are cross-pollinated and require hand pollination to set seed, and even more species require pollination between different plants of the same species. Therefore, at least two plants of the same species must be prepared. Pollination must be carried out when the stamens' anthers have split open, the pollen has matured, and the pistil stigma is fully secreting sticky fluid. However, the maturation times of the stamens and pistils are not necessarily the same across different species. If the mother plant blooms later than the father plant, the father plant can first be placed in a cool, shaded spot to delay its blooming, or the father plant's pollen can be collected and stored in a cool, dry place. When the mother plant's pistil matures, take the pollen out and pollinate. For most species, the pollination success rate is highest 1-2 hours after noon on the second day of blooming. Use a clean brush to dip up the pollen and lightly apply it to the mother plant's stigma, or use fine tweezers to pick up the pollen and place it on the stigma. If the weather is extremely hot, the humidity is too high, or there is water on the flower, the fertilization rate will not be high.

2. Remove the petals: After pollination, if the ovary gradually swells, it indicates that pollination has succeeded. At this point the withered petals can be cut off to prevent mold and rot. The plant should be protected from rain and water splashing, and fertilizer and water management should be strengthened.

3. Collect seeds in time: Cactus fruits generally mature in 50-60 days. Some species produce berries, which are easily pecked by birds and other small animals when ripe, so the fruits should be protected with netting. Some fruits have skins that split easily, so timely harvesting must be paid attention to. Harvested berries should have the flesh removed, and the seeds should be washed clean and then drained of water. The resulting seeds should be put into paper bags and placed in a dry, cool place, with the seed name and harvest date noted.

4. Disinfection and seed soaking: The soil used for sowing should be disinfected river sand or a sand-mixed leaf mold soil. It must be disinfected by frying in a pan or steaming, and chemical agents must not be used for disinfection. Before sowing, moisten the pot soil by the soaking method, then soak the seeds in 1% formalin or 2.5% copper sulfate solution for 15 minutes, take them out, rinse them, and they are ready for sowing. Small seeds can be mixed with sand and evenly broadcast on the soil surface, with no need to cover with soil. Large seeds can be sown in holes at a spacing of 5 mm × 5 mm.

5. Sow at the right time: The best time for seed propagation of cacti is spring and autumn, when the temperature difference between day and night is large. A large temperature difference can not only increase the germination rate but also speed up the growth of the seedlings. Sowing on cloudy and rainy days should be avoided; sunny weather should be chosen. In a greenhouse, seed propagation can be carried out in all four seasons.

6. Careful management after sowing: After sowing, a glass pane should be placed over the pot, and a gap must be exposed at fixed times each day for ventilation. Generally, cactus species can germinate within 15 days. After germination, the dryness and moisture inside the pot should be carefully observed, keeping the surface of the pot soil somewhat moist. The light for the seedlings must be controlled; white paper with holes punched in it can be placed over the glass. As the seedlings grow, replace the white paper, making the holes correspondingly larger and more numerous to allow more light. The seedling-stage management of cacti should strictly control temperature, humidity, water, light and ventilation. In the peak growing seasons of spring and autumn, maintain a relatively large day-night temperature difference and give the seedlings light at appropriate times and in appropriate amounts. In summer, strengthen ventilation and lower the temperature. In winter, place them in a warm spot indoors and appropriately increase light, but not excessively. Watering should mainly use the soaking method; the pot surface just needs to be moist.

Cactus Cutting Propagation

1. Cutting time: Under normal conditions, cutting in May and June is most suitable. Where there is a greenhouse, it can be done all year round.

2. Preparation of the substrate: Cacti are drought-tolerant and tolerate poor, thin soil, and they dislike waterlogging. Therefore, the substrate must have good air permeability, good drainage, and the ability to stay moist; vermiculite, perlite and the like are best. A mix of 4 parts coarse river sand, 3 parts loam soil, 2 parts leaf mold and 1 part rice husk ash can also be used.

3. Cutting the cuttings: From a mother plant with strong growth and no pests or diseases, select robust, mature stem segments as cuttings. Use a rust-free scraper to cut the cuttings from the mother plant; before and after each cut, wipe and disinfect the tool with alcohol.

4. Dry the cuttings: Freshly cut cuttings should not be planted immediately. First place them indoors in relatively dry air to dry for 5 to 7 days, and plant them only after the cut surface has dried and the stem flesh has begun to shrink.

5. Hormone soaking: For varieties that are difficult to root, soaking the base of the cuttings in plant growth hormone can greatly increase the survival rate. The method is: soak the base of the cutting in a 50 to 100 ppm GGR (plant growth regulator) solution for half an hour to one hour, or soak the base of the cutting in a 200 ml/L naphthalene acetic acid solution for 4 hours. For most other varieties that root easily, cutting can be done without hormone treatment.

6. Cutting: Bury the base of the cutting shallowly into the substrate; never bury it too deep, which would cause rot. At this point the cutting is difficult to stand upright (because it has softened after drying), so it can be laid flat on the substrate; it can also be supported with a small wooden stick, then use both hands to gently press the soil on either side of the cutting so that it fits closely with the soil.

7. Management after cutting

① Water management: When cutting, the substrate should preferably be moist; if it is too dry, rooting is difficult, so a little water can be poured in from the edge of the pot. But the substrate must not be too wet, otherwise the cutting will easily rot. Before rooting, keep the pot soil consistently moist. To reduce water evaporation, a plastic bag can be placed over the pot. After about a month the cutting will root, and at that point the plastic bag should be removed immediately.

② Light management: Before rooting, protect from direct sunlight and keep the plant in a semi-shaded spot. After rooting, routine management of water and light can be carried out.