Many people like cactus, because cactus can be placed next to the computer to absorb radiation, which is good for women's skin. However, if the cactus is not well cared, it is easy to turn yellow or even rot to death. What is the reason why the cactus turns yellow? How to take care of cactus? Let's get to know it.
1. Underwatering or overwatering
If the soil is too wet for a long time due to excessive watering, Golden Barrel Cactus
, for example, it will lead to extreme hypoxia in the root, cactus rot, affect the normal absorption of nutrients and water in cactus, and cause the leaves to turn yellow and fall off; Similarly, if watering is wet up and dry down, it will also cause dark yellow leaves, no luster, and finally wither and fall off. At this time, watering should be stopped, only appropriate water should be retained, and the soil should be kept breathable, and the cactus will gradually recover. (Read more about Golden Barrel Cactus
2. Not Enough or Too Much Sun Exposure
Cactus is a tropical plant. What we are most afraid of is sunshine. If we put cactus in front of a cool desk for a long time, it must be very unfavorable to its growth. Without the nutritional supply of sunlight, the immunity and resistance of cactus will be weakened. If coupled with an airless environment, it is simply the "best negative teaching material" for the maintenance of cactus. Therefore, when we are maintaining cactus, we should choose a sunny environment for it, which will not only make it vibrant, but also help the evaporation of water and reduce the possibility of ponding and rotten roots.
3. Too Much or Not Enough Fertilizer
The growth of cactus needs fertilization. If there is unreasonable fertilization in fertilization, such as less fertilization, the plant will gradually turn yellow due to the lack of necessary nutrients. If too much fertilizer is applied, it will cause serious fertilizer damage and lead to the yellowing of cactus
. Generally, when we apply fertilizer to cactus, for example, we can apply fertilizer every half a month during growth, and the fertilizer is mainly rotten liquid fertilizer. In autumn and winter, fertilizer can be applied once a month. When fertilization is too much, we can change the pot of cactus, and then replant it.
4. Temperature Change
Cactus likes a warm environment. The most suitable temperature for growth is about 25 ℃. When the temperature is higher than 35 ℃ or lower than 10 ℃, it has a great impact on the plant. Without temperature control, the cactus will turn yellow. If the ambient temperature of cactus is too high, cooling measures need to be taken. The specific methods can be carried out through shading, spraying, ventilation and other methods. If the temperature is too low, we should timely move the plants indoors for maintenance.
5. Soil Type
Cactus likes sandy soil with smooth drainage and moderate fertility. It can also grow in poor soil. When we plant cactus in flowerpots, we can use the same amount of peat soil and fine sand; It can also be used after mixing crushed pine needles and fine sand; It can also be mixed with rotten leaf soil and fine sand. If the soil and water are alkaline, or lack of soluble iron, the cactus will gradually wither and yellow. At this time, we can pour alum fertilizer water in time. If the soil becomes acidic due to the loss of chemical elements in the soil, alkaline solutions such as calcium, magnesium and phosphorus can be applied for soil neutralization to protect the cactus.
6. Suddenly Repotting
Once the cactus becomes soft after changing the basin, it is difficult to recover, because too many root systems are damaged during transplantation, or watering is too frequent after changing the basin (it will be worse if you change a large basin), which fails to dry the basin soil, poor ventilation and poor lighting in the environment, so the disease is inevitable. In view of this situation, the cactus turns yellow
and soft without decay, we can strengthen management and slowly recover, but it is bound to affect the growth in the future, so we must choose to change the pot at the right time and do not harm the cactus root system.
A major reason for the yellowing of cactus is the occurrence of diseases and pests, such as locusts, red spiders and scale insects. When pests occur, they will suck the juice, destroy the chlorophyll and finally turn yellow. First of all, if we find that there are a small number of diseases and pests in cactus, we can remove the insect leaves first, make a good ventilation environment, spray wet water to keep the air moist. If cactus pests are serious, we can spray 40% dimethoate emulsion 600 ~ 800 times.
We usually buy cactus potted plants in the flower market, but the more choices we make, the greater the probability of intermingled good and bad. If we don't pay attention, we are likely to buy a pot with poor ball planting and disease. Such potted plants may be grafted balls and have no roots, so they are very easy to infect bacteria; There may also be cactus that squeeze and collide with each other during transportation. Such cactus will stab the ball into the ball meat, resulting in wounds or holes. The wounds are very insignificant and difficult to detect by the naked eye, but they will affect the growth of the ball. Once the environment changes or adverse objective factors appear, the resistance of the cactus will be weakened and turn yellow, To warn the master that he has been traumatized. Therefore, we must observe carefully when buying potted plants to avoid buying inferior plants.
9. Exposure to Chemicals
Everyone should be familiar with color cactus. In order to attract customers, some businesses often spray some color reagents on the surface of cactus to attract everyone to buy. After spraying this color chemical, it is easy to block the pores on the surface of the cactus, resulting in difficulty in respiration and photosynthesis in the later stage of the plant. The cactus turns yellow, shrivels, and even withers and dies. Therefore, we should avoid buying this kind of cactus.