How to Grow Cacti? Teaching You the Correct Cultivation Methods
From growing wild to being widely brought into homes for cultivation, cacti reflect a trend among city residents in choosing potted flower varieties. Because apartment space is limited and the air is relatively dry, large or more delicate potted flowers often do not grow well; only small, drought-tolerant, easy-to-manage varieties with high ornamental value are most suitable, and cacti happen to meet all these requirements.
Home Cultivation Methods for Cacti
For home cultivation of cacti, it is best to choose small, free-flowering ball-type species. When cultivating them, do not assume that because these plants are drought-tolerant you can neglect normal watering and fertilizing. For indoor cultivation, you can use wire and plastic film on a windowsill to create a sealed space with high temperature and high humidity; under such conditions most cacti not only grow quickly but also have a crystal-clear luster.
The potting soil should be sandy soil or sandy loam that drains and breathes well and contains calcareous material. Newly planted cacti should not be watered at first; simply mist them several times a day with a spray bottle. Only after half a month can you water lightly, and only after one month, when new roots have grown, can you water normally. In winter, when temperatures are low and the plants enter dormancy, watering should be restricted. After spring begins, as temperatures rise, the plants gradually come out of dormancy and watering can be gradually increased. Apply a diluted, well-rotted liquid fertilizer once every 10 days to half a month; do not fertilize in winter.
Under ordinary residential conditions, by making full use of space, it is not difficult to grow dozens of pots of various cacti and arrange a small “cactus garden.” At the turn of spring and summer, when the assorted cacti on the windowsill bloom with a dazzling array of flowers, resting under such conditions after work can not only relieve fatigue but also be an enjoyment of natural beauty.
Propagation Methods for Cacti
The commonly used propagation methods for cacti are four: cuttings propagation, division propagation, seed propagation and grafting propagation.
1. Cuttings Propagation Method
① Cutting time: Under normal conditions, May to June is the most suitable time for cuttings. Where a greenhouse is available, it can be done all year round.
② Preparation of the substrate: Cacti are drought-tolerant and tolerant of poor soil, and they dislike waterlogging. Therefore, the substrate must have good breathability, good drainage and the ability to retain moisture; vermiculite, perlite and the like are best. You can also mix it from 4 parts coarse river sand, 3 parts loam, 2 parts leaf mold and 1 part rice-husk ash.
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 Drying the cuttings: Freshly cut cuttings should not be planted immediately. First place them in a relatively dry indoor area to dry for 5 to 7 days, and only plant them after the cut surface has dried and the stem flesh has begun to shrink.
⑤ Hormone soaking: For varieties that root with difficulty, soaking the base of the cuttings in plant growth hormone can greatly increase the survival rate. The method is: soak the base of the cuttings in a 50 to 100 ppm GGR (plant growth regulator) solution for half an hour to one hour, or soak the base of the cuttings in a 200 ml/L naphthaleneacetic acid solution for 4 hours. For most other varieties that root easily, hormone treatment is not necessary before planting.
⑥ Planting: Bury the base of the cutting shallowly into the substrate; never bury it too deep, as this causes rot. At this point the cutting is difficult to stand upright (because it has softened after drying), so you can lay it flat on the substrate; you can also prop it up with a small wooden stick, then gently press the soil on both sides of the cutting with both hands so that it fits closely with the soil.
⑦ Management after planting: First, water management. At planting time the substrate should be moist; if it is too dry, rooting is difficult, so you can pour a little water along the edge of the pot. But the substrate must not be too wet, otherwise the cuttings easily rot. Before rooting, keep the potting soil moist at all times. To reduce water evaporation, you can cover the pot with a plastic bag. After about one month the cuttings will root, and at that point the plastic bag should be removed immediately. Second, light management. Before rooting, protect them from strong sunlight and keep them in a semi-shaded place. After rooting, routine management of water and light can be carried out.
2. Division propagation: Many cacti produce offsets. For example, ball-type cacti grow small offsets on the stem, while prickly pear cacti or segmented cacti all produce offsets. For these varieties we must put in a bit more effort: you can use a knife to cut off the growing point of the cactus, and after cultivating it for a period of time, many small offsets will grow near the growing point. When the offsets have grown to an appropriate size, you can cut them off and propagate them by cuttings.
3. Seed propagation: The process of using seeds to propagate cacti is also very interesting, because only through seed propagation can you hybridize some new varieties yourself and bring yourself some surprises. In seed propagation, pollinating the cactus flowers is the first step of the whole process, because most cacti cannot self-pollinate, so you have to play the “matchmaker” and give them a helping hand. You can use a cotton swab to apply pollen onto the stigma, then quietly wait for good news. Before long, when the fruit is plump and ripe, you can take out the seeds and wash them. Because cactus seeds are very small, it is best to wrap the seeds in gauze and rinse them under running water, then scatter the seeds evenly over thoroughly moistened potting soil, place them in a dark place and maintain the temperature at around 20°C; in winter the temperature must not be lower than 10°C. When the seeds develop into seedlings, the first transplanting can be carried out, and after continuing to cultivate them in a dark place for some time, they can be planted into small pots; alternatively, the root system of the seedlings can be cut off and grafted onto a rootstock.
4. Grafting propagation: Grafting is a horticultural technique commonly used for cacti. Because the root systems of some cacti are very fragile, after long-term cultivation the root system gradually loses its original function and disappears, and the plant thereby loses its vitality. Grafting is the panacea for saving these cacti. In addition, speeding up the growth rate of cacti or enabling plants with root rot to continue growing after the affected parts are cut away can all be achieved by grafting. When grafting, the rootstock chosen -- the triangular column -- is one kind of such cactus. The method is to cut off the growing point of the triangular column and make a slanted cut on the ribs, then place the cactus whose root system has been removed in the center of the rootstock, then fix the position with string or a heavy object; after 1 to 2 weeks, the string and heavy object can be removed.
Pest and Disease Control for Cacti
1. Cabbage caterpillars, locusts: Spray with a 2000-fold dilution of 25% deltamethrin.
2. Control of red spider mites: Prevention should be the main approach. The cultivation environment should be properly ventilated, but a certain humidity should be maintained to avoid stuffiness and dryness. Commonly used agents include a 1000- to 1500-fold dilution of 40% omethoate and a 1000-fold dilution of 40% dicofol. In hot, dry seasons, spray to kill them once every 7 to 10 days; before overwintering, spray thoroughly to kill them.
3. Control of scale insects: Because adult scale insects have a waxy shell on their bodies, chemical control often cannot achieve the expected results, so prevention should be valued even more. The cultivation site should be kept clean. When scale insects are found, they can be scraped off promptly with a bamboo strip, or branches with many insects can be cut off and burned. Chemical control of scale insects must be carried out shortly after the eggs hatch and before the insect bodies have grown their waxy shells, and repeated spraying is required for it to be effective. The agents usually used include a 1000-fold dilution of 50% malathion, an 800-fold dilution of 25% phosmet emulsifiable concentrate, and a mixture of 40% omethoate emulsifiable concentrate and 80% dichlorvos emulsifiable concentrate diluted with water 1000-fold.
4. White grubs, wireworms, cutworms: Drench with an 800- to 1000-fold dilution of 50% phoxim.
5. Control of rot disease: Prevention should be the main approach in controlling rot disease. First, improve the environmental conditions of the cultivation site; this can greatly reduce the occurrence and spread of pathogenic fungi. Second, strengthen cultivation management. Do not mix undecomposed organic fertilizer into the planting soil, and it is better to apply fertilizer lightly than heavily. If waterlogging is found, drain it promptly; part of the damaged root system can be cut off, and the plant can be replanted after the wounds have dried. Regularly spraying fungicide on the cacti or in the surrounding environment has a certain effect on preventing the occurrence of rot disease. Commonly used fungicides include zineb, carbendazim and thiophanate.
6. Golden spot disease, sunken spot disease and fusarium wilt: Spray with a 800-fold dilution of 75% chlorothalonil or a 600- to 800-fold dilution of 50% carbendazim or 70% thiophanate-methyl;
7. Rust disease: Spray with a 2000- to 3000-fold dilution of 25% triadimefon.