How to grow a cactus? Master these eight key growing factors
The cactus is a common indoor plant, and its tenacious vitality means it can survive well without careful attention, but with proper care, a cactus grows quickly and soon produces beautiful little flowers, with its lovely spherical shape and eye-catching blooms. Everyone admires them, so what are the methods for growing a cactus? Below are the eight key factors for growing a cactus.
1. Temperature
The cactus likes high temperatures and a dry environment. In winter, the room temperature should stay above 20°C during the day and not below 10°C at night. Temperatures that are too low easily cause root rot.
2. Light
The cactus requires plenty of sunlight, but in summer it must not be exposed to strong direct sun and needs appropriate shading. For indoor cultivation, artificial lighting can be used to promote robust growth.
3. Potting soil
The soil for potted cacti must be well-draining, breathable, lime-containing sandy soil (or sandy loam). It can be mixed from 2 parts loam and 2 parts leaf mold, 3 parts coarse sand, plus 1 part limestone gravel or old lime wall debris discarded when old buildings are demolished. It can also be mixed from 2 parts loam and 2 parts coarse sand, with 1 part each of crushed brick, leaf mold and old lime wall debris. When planting, a small amount of crushed brick and tiles should be placed at the bottom of the pot to ensure good drainage.
4. Planting
Planting into pots is best done in early spring. The flower pot should not be too large; it should be just enough to hold the ball with a little space around it. If the pot is too large, the water cannot be absorbed after thorough watering, air cannot circulate in the pot, and the roots easily rot. A few taproot types, as well as Lophophora and Echinocactus, require deeper cylindrical pots. Shallow-rooted types such as Mammillaria and Rebutia can use shallower ordinary flower pots.
5. Repotting method
When repotting, part of the old roots should be trimmed off. After drying for 4-5 days, plant it into the pot. Do not plant it too deep; the root crown of the ball should be level with the soil surface. To avoid root rot, do not water newly planted cacti; simply mist 2-3 times a day, and after half a month a small amount of water can be given. Only after one month, when new roots have grown, can watering be gradually increased.
6. Watering
Summer is the growing season for cacti. With high temperatures, water demand is great, and they must be watered thoroughly. It is best done in the early morning or evening when temperatures are low; watering at hot noon can easily cause sunburn on the ball. During the hot plum rain season, watering should also be appropriately restricted. For cacti with a depression at the top, be careful not to let water get into the depression, as this can cause rot; this is even more important when watering in the evening.
During winter dormancy, watering should be restricted, just enough to keep the potting soil from becoming excessively dry. The lower the temperature, the more the potting soil should be kept dry. Mature large balls are more drought-tolerant than small seedlings. In winter, watering should be done on sunny mornings. As the temperature rises, the plant will gradually come out of dormancy, and only then can the frequency and amount of watering gradually increase.
7. Fertilizing
Potted cacti can also be appropriately fertilized during the growing season, especially those grafted onto Hylocereus undatus, which deserve even more attention when it comes to fertilizing. A fully decomposed, dilute liquid fertilizer can be used, applied once every 10-15 days. After early autumn, control fertilizer and water; generally once a month is enough, and stop fertilizing in early October. If fertilizer is not controlled and the cactus is allowed to keep growing, the tender ball is susceptible to cold damage when overwintering.
When fertilizing, be careful not to get it on the ball; if it does get on, immediately spray it off with water.
8. Pest and disease control
In environments with high temperatures and poor ventilation, pests and diseases are likely to occur. For diseases, spray carbendazim or thiophanate; for pests, spray dimethoate to kill them. No matter which liquid medicine is sprayed, it must be done outdoors.
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