Potted Cactus Growing Methods and Fertilizers for Thick, Robust Growth
When caring for cactus family flowering plants, many people often fall into cultivation pitfalls: simply giving the plants sunlight year-round, providing high-temperature and drought conditions, using coarse sand for planting, and so on, believing this will grow these flowers well. In fact, this is not the case. To cultivate and manage cactus family flowering plants well, you must care for them according to the place of origin, morphology, and habits of different species and varieties.
According to place of origin and morphology, cactus family flowering plants are divided into two types: terrestrial and epiphytic. Terrestrial cacti originate from the arid desert or semi-desert regions of tropical and subtropical America. Their stems are modified into spherical or columnar shapes, and their leaves are modified into spine-like needles. From April to October each year is the rainy season, the water-absorbing growth period, and from October to March of the following year is the water-controlled dormancy period. Epiphytic cacti originate from tropical rainforests, with flat stems and fewer spines, no dormancy period or an inconspicuous one, and they require semi-shade, year-round warmth, moisture, and high air humidity environmental conditions.
I. Repotting
(1) Repotting Time
Usually once a year in spring (mid-March to early April) or autumn (September to mid-to-early October), repot and change the soil. Stop watering 3 to 5 days before repotting. When repotting, first remove the plant from the pot, shake the soil off the roots clean, cut off all old roots, rotten roots, and half-withered roots. Be careful not to cut off the main root, the so-called "radish root." Keep healthy roots only 3 to 4 cm long. Place the plant after root pruning in a cool, ventilated place to dry for 5 to 6 days, then replant. This way, rooting is fast and good. If there are young offsets beside the old plant, they can be broken off, their roots properly trimmed, and then planted separately to become new plants.
(2) Preparation, Disinfection, and Planting of Growing Medium
For terrestrial types, use 5 parts loam soil, 3 parts peat soil or leaf mold, and 2 parts coarse sand, plus a little slaked lime or old wall debris ash, to prepare a calcareous sandy soil or sandy loam with good drainage and aeration. For epiphytic types, use 1 part compost soil, 1 part coarse sand, and 1 part peat soil, plus a little bone meal, to prepare a neutral or slightly acidic fertile growing medium rich in humus with good drainage and water retention. After the growing medium is prepared, spray each cubic meter with 400 to 500 ml of a 50-fold dilution of 40% formaldehyde. Apply 10 to 20 days before use, sprinkle on the growing medium and mix evenly, cover with plastic film, open the film 1 week before planting, and plant after the medicinal smell has dissipated. When planting new plants, place a layer of gauze mesh over the drainage hole at the bottom of the flower pot to prevent pests, then cover the gauze with tiles or similar to facilitate drainage. Add potting soil to 2 to 3 cm from the pot rim to make future watering convenient. Since the soil is moist, there is no need to water immediately after planting. After 7 to 10 days, water once thoroughly. The planted plant should be placed in a bright place without direct sunlight for care. After about 10 days, new roots will sprout, then water once more and resume normal management.
II. Cultivation and Management Techniques
(1) Watering and Misting
Terrestrial cacti have obvious growth and dormancy periods. Water during the growth period, and water less or not at all during dormancy. For epiphytic types, if the winter temperature is kept above 12°C, they can be watered and misted year-round; if the winter temperature is kept below 12°C, watering can be reduced as appropriate and misting stopped. When watering, follow this principle: "Water thoroughly when dry, do not water when not dry." The water temperature should be as close as possible to the soil temperature. In summer, water early (before sunrise) and late (after sunset); in winter, water from 10 to 11 a.m. Also, pour water directly onto the potting soil, otherwise it will affect the appearance of the spines. In addition, in summer, sprinkle water on the ground to increase air humidity.
(2) Fertilizing
Follow this principle for fertilizing: timely, appropriate amount, and according to the plant. Fertilize in spring and autumn, once every 20 days, and choose to do so in the early morning or evening of a sunny day. If the potting soil is relatively dry, sprinkle a little water on the potting soil before fertilizing. A concentration of 0.05% to 0.2% is suitable. The next morning, water once thoroughly for better results. Terrestrial types require fertilizers rich in potassium and phosphorus and low in nitrogen, while epiphytic types require more nitrogen fertilizer.
(3) Light
Terrestrial types prefer sufficient sunlight, especially in winter when full sunlight is even more necessary. Generally, tall columnar and flat cacti are more tolerant of strong light and can be placed outdoors in summer without shading. Smaller spherical types prefer semi-shade conditions in summer. During the hot summer months of June to August, cover a round piece of plastic film over the top growth point and surrounding area of the golden barrel cactus (Echinocactus grusonii) so that all parts of the sphere grow evenly. Epiphytic cacti require semi-shade conditions year-round.
(4) Temperature
The suitable growth temperature for cacti is between 20 and 35°C. Terrestrial types do not require very high temperatures during winter dormancy. While keeping the potting soil dry, maintaining a temperature of 4 to 7°C is sufficient. Epiphytic types, however, require higher temperatures in winter, preferably maintaining 10 to 13°C or higher. When summer temperatures reach 30 to 35°C, most cacti slow their growth rate, and sometimes the stems of certain species turn yellow or become scorched. At this time, shading must be provided and more water sprinkled on the ground to lower the temperature.
(5) Air
Most cactus family flowering plants originate from open desert areas with good ventilation and fresh air. Therefore, during the hot midsummer weather, ventilation and cooling work at the cultivation site should be done well. Cultivation greenhouses should be chosen in environments with air circulation, and more windows, skylights, and similar ventilation openings should be installed to allow ventilation and air exchange during hot weather. If necessary, equipment such as exhaust fans, blowers, or electric fans can be installed to strengthen the air circulation effect of the environment, so as to help cactus family flowering plants safely pass the summer.
(6) Pests and Diseases
The pathogens harming cactus flowering plants include bacteria and fungi, but the problem is not very serious. As long as cultivation conditions are improved, management measures are appropriate, and prevention and elimination of pests and diseases are combined, good results are easily obtained. The more common pests and diseases mainly include:
1. Rot disease. Its pathogens include both bacteria and fungi. The occurrence of this disease is often related to improper watering, poor drainage of the potting soil, and persistently excessive moisture. After discovering a diseased plant, immediately use a sharp knife to cut off the diseased tissue, and apply wood charcoal powder or sulfur powder to the cut. At the same time, reduce watering or repot, and separately take cuttings or graft. It is best to regularly spray the planting site and plants with an 800- to 1000-fold dilution of 40% copper oxychloride suspension for prevention, but the main thing is still to improve ventilation conditions and avoid persistently excessive moisture.
2. Damage by insects and other animals. Mainly include scale insects, red spider mites, and slugs, etc. To control scale insects, spray a 1000-fold dilution of 50% omethoate emulsifiable concentrate; to control red spider mites, spray a 600-fold dilution of 20% dicofol wettable powder or a 1000-fold dilution of 40% dicofol emulsifiable concentrate; to control rats and woodlice, spray a 2000-fold dilution of chlorpyrifos around flower stands and flower pots; to control snails and slugs, sprinkle lime powder around flower pots, or apply 8% metaldehyde granules; to control cockroaches and ants, place cockroach and ant killing drugs or mix sugar water with trichlorfon to poison them.
Cactus family flowering plants are divided into two major categories in cultivation: terrestrial cacti and epiphytic cacti. These two major categories of cactus flowering plants have completely different requirements for temperature, light, and water during overwintering. But the author believes that their overwintering management should all begin in autumn. After mid-autumn, cactus plants should receive as much light as possible. After late autumn, watering should be gradually reduced until stopped. If necessary, a small amount of potassium chloride solution can be applied to increase the plant's body fluid concentration and enhance cold resistance. From late autumn to early winter, do not rush to move cactus flowering plants indoors too early. Instead, let the plants receive full sunlight during the day outdoors and low-temperature training at night as much as possible. If no cold wave occurs, cactus flowering plants can be moved indoors only when the nighttime minimum temperature drops to 4°C. Do not interrupt in between. Cactus flowering plants treated in this way generally have somewhat enhanced tolerance to low temperatures, which is beneficial for overwintering.
Terrestrial cacti originate from arid regions, are extremely drought-tolerant, and mostly have a dormant habit. After the beginning of winter, watering should be absolutely prohibited, keeping the potting soil dry to promote entry into dormancy. If the temperature is not below 2°C to 5°C, they can safely overwinter. This is because cactus plants have the strongest cold resistance during dormancy. If improper watering is done in winter, breaking their dormancy and restoring their physiological activity, the plant's cold resistance decreases and () it is prone to () freezing and rotting. During overwintering, if the room temperature is too low, the plant can be covered with plastic for warmth. Even when necessary, the plant can be wrapped in cotton and straw, and the whole pot placed in a wooden box or cabinet for storage. Even if the temperature is below 0°C, it can safely overwinter. Sometimes, in households with many flowers planted and limited space and poor conditions, after entering winter, once the potting soil is on the dry side, the plant can be removed from the potting soil and the bare roots wrapped in cotton and straw, then placed in a box or cabinet for storage, which both saves space and provides warmth. When the temperature rises back to 10°C, remove the wrapping material from the plant, repot it, place it indoors in a dry place, let it gradually adapt to sunlight, and appropriately mist and water at noon to gradually restore growth. Although doing this has some effect on the plant's growth the following year, for households lacking space and with poor warmth-retention facilities, it is still a good overwintering method.
Epiphytic cacti originate from tropical rainforests with higher air humidity, such as Epiphyllum oxypetalum, Epiphyllum hybridum, and Schlumbergera truncata. They also need higher temperatures and air humidity in winter and have no dormancy period, so overwintering management is more difficult than for terrestrial cacti. An ideal overwintering environment needs to be created for them. The author installed a 5 cm thick glass box beside a south-facing window, laid a layer of charcoal ash at the bottom, placed a 100w light bulb inside for heating, put the cactus in the box, covered it with plastic film, and buried the pot in the charcoal ash. When the weather is clear and fine, appropriately lift the film for ventilation; when the weather is bad, cover the plastic film, and if necessary cover with a cotton quilt or straw curtain and turn on the light bulb for heating. Even on clear nights, the glass box should be covered with a straw curtain or cotton quilt for warmth. In this way, the temperature inside the box is generally maintained between 12°C and 13°C. Usually, a small amount of water can be given to keep the potting soil in a semi-dry state. Also, as appropriate, sprinkle water on the glass box walls to maintain relatively high air humidity inside the glass box. This can meet the water needs of epiphytic cacti, keep the plants at a low level of growth, and benefit growth and flowering the following year. It should be explained here that if there is no glass box, building a warmth-retention shed with double-layer plastic film and carrying out the same management can also allow epiphytic cacti to safely overwinter.
Because the succulent flowers of the golden barrel cactus have peculiar forms, are easy to cultivate, and can purify indoor air, many people are very interested in growing golden barrel cacti. So, how can golden barrel cacti be grown well? The author believes there are the following aspects:
1. Temperature: The golden barrel cactus likes high temperatures and dry environments. In winter, the room temperature should be kept above 20°C during the day and not lower than 10°C at night. Too low a temperature easily causes root rot, but too high a temperature also easily leads to scale insect damage.
2. Light: The golden barrel cactus requires sufficient sunlight, but in summer it should not be exposed to strong direct sunlight and needs appropriate shading. For indoor cultivation, light can be used to promote healthy growth.
3. Soil: The golden barrel cactus is suitable for growing in well-drained sandy loam. For indoor cultivation, artificial growing medium is mostly used, usually prepared by mixing half peat soil and half fine sand; crushed pine needles mixed with fine sand can also be used as a prepared growing medium for planting.
4. Watering: The golden barrel cactus requires a dry environment and is afraid of water accumulation in the potting soil. Generally, keep the potting soil "dry when it should be dry, wet when it should be wet." It is best to use water that has been left to stand for watering.
5. Fertilizing: When repotting the golden barrel cactus, apply a small amount of base fertilizer at the bottom of the pot, such as horseshoe pieces, bean cake, or sesame paste residue. During the growth period, water once every half month with fermented organic liquid fertilizer (a concentration of 20% is suitable). Never let the fertilizer concentration be too high.
6. Pest and disease control: In high-temperature, poorly ventilated environments, pests and diseases easily occur. For diseases, spray carbendazim or thiophanate-methyl; for pests, spray dimethoate to kill them. No matter which medicinal solution is sprayed, it must be done outdoors.
The golden barrel cactus can be propagated by grafting, generally using the flat grafting method. The rootstock can be selected from three-ribbed cereus or robust pad stems. The specific method: first cut off the top of the rootstock, make a horizontal cut at the base of the scion, join the two together, and then bind them with string. After two weeks, remove the string.
(Text/Caiba caiba_org)