The propagation methods of Croton (Codiaeum variegatum) 'How to propagate Croton (Codiaeum variegatum)?'

Selecting Seeds: Before sowing, it's essential to select good seeds, as the success of the sowing depends on the seed selection.

1. It's best to use seeds harvested in the current year. The longer seeds are stored, the lower their germination rate.

2. Choose seeds that are full and free from defects or abnormalities.

3. Select seeds that are free from diseases and pests.

Disinfection: Disinfection involves two concepts, one is disinfecting the seeds, and the other is disinfecting the sowing matrix. At home, seeds are commonly disinfected by soaking in hot water at about 60°C for 15 minutes, followed by germination in warm water for 12-24 hours. For disinfecting the sowing matrix, the best method is to heat it in a pan, which can kill any pests and diseases.

Germination: Soak the seeds in warm water (about the same temperature as face-washing water) for 12-24 hours until they absorb water and swell. For seeds that germinate easily, this step can be omitted.

Sowing: For tiny seeds that are difficult to handle by hand or other tools, moisten one end of a toothpick and stick the seeds one by one onto the surface of the matrix. Cover the matrix with a 1 cm layer of soil, then place the seedling pot in water with a depth of 1/2 to 2/3 of the pot's height, allowing the water to slowly rise (this method is called "pot immersion"). For larger seeds that can be handled, place them directly into the matrix with a spacing of 3x5 cm. After sowing, cover with soil twice to three times the thickness of the seed. After sowing, use a sprayer or fine-mist sprinkler to moisten the sowing matrix, and water again when the soil is slightly dry, being careful not to apply too much force to avoid washing away the seeds.

Management after Sowing: After sowing in late autumn, early spring, or winter, you can wrap the pot in plastic film to keep it warm and moist during cold spells. Once seedlings emerge, promptly remove the film and expose the seedlings to sunlight in the morning before 9:30 or in the afternoon after 3:30, otherwise, they will grow very weakly. After most seeds have germinated, thin the seedlings appropriately: remove sickly or unhealthy seedlings to leave some space between the remaining ones. When most seedlings have grown 3 or more leaves, they can be transplanted.

Two: Cutting

Commonly used in late spring and early autumn, cuttings are taken from the current year's branches for softwood cuttings, or from last year's branches for hardwood cuttings in early spring.

Cutting Medium: This is the soil or materials such as river sand, peat moss, etc., used for cutting. It's difficult to obtain ideal cutting medium at home, so it is recommended to use the pre-prepared and disinfected cutting medium provided by this site; medium-coarse river sand is also acceptable but should be rinsed with clean water before use. Do not use sea sand or river sand from saline-alkaline areas as they are not suitable for the growth of flowering plants.

Selection of Cutting Stems: For softwood cuttings, select strong branches during the vigorous growth period from late spring to early autumn. Cut the branches into segments 5-15 cm long, each with more than 3 leaf nodes. When taking cuttings, the upper cut should be about 1 cm above the upper leaf node, and the lower cut should be about 0.5 cm below the lower leaf node at a diagonal, ensuring both cuts are smooth (the knife should be sharp). For hardwood cuttings, after the temperature rises in early spring, select strong branches from the previous year. Each segment usually retains 3-4 nodes and is cut in the same way as softwood cuttings.

Management after Cutting:

Temperature: The optimal temperature for root formation of cuttings is 20-30°C. Below 20°C, root formation is difficult and slow; above 30°C, the upper and lower cut ends of the cuttings are easily infected by pathogens and rot, and the higher the temperature, the higher the proportion of rot. When the temperature is low after cutting, the main measure to keep warm is to wrap the pot or container used for cutting with plastic film. When the temperature is too high after cutting, the main measure to cool down is to shade the cuttings, reducing 50-80% of sunlight, and spray water 3-5 times a day, more frequently on sunny days or high temperatures, and less or not at all on cloudy or low-temperature days.

Humidity: After cutting, it is necessary to maintain the relative humidity of the air at 75-85%. The basic requirement for root formation in cuttings is to ensure that the cutting is fresh and can perform photosynthesis to produce root-forming substances before it roots. However, cuttings without roots cannot absorb enough water to maintain their internal water balance, so it is necessary to reduce water evaporation from the cuttings by spraying: under shaded conditions, spray the cuttings 3-5 times a day, more frequently on sunny days or high temperatures, and less on cloudy or low-temperature days. However, excessive spraying can cause the cuttings to be infected by pathogens and rot, as many types of pathogens are present in water.

Light: Cutting propagation cannot do without sunlight, as the cuttings still need to photosynthesize to produce nutrients and root-forming substances to meet their rooting needs. However, the stronger the light, the higher the temperature inside the cutting, the more vigorous the transpiration, the more water consumed, which is not conducive to the survival of the cutting. Therefore, after cutting, it is necessary to

shade 50-80% of the sunlight until the roots are formed, then gradually remove the shading net: remove the shading net at 4:00 pm on sunny days and cover it again before 9:00 am the next day.

Layering: Select strong branches and strip a circle of bark about 15-30 cm below the tip. The width of the wound should be about 1 cm and deep enough to remove just the epidermis. Cut a piece of film 10-20 cm long and 5-8 cm wide, place some moist garden soil on it, and wrap the ring-stripped part as if bandaging a wound, tying the ends of the film tightly and leaving the middle bulging. After about 4-6 weeks, roots will form. Cut the branch below the roots, and a new plant will be formed. Potting or Transplanting: When potting young seedlings or repotting large plants that have been growing for a few years, first place a 2-3 cm thick layer of coarse-grained matrix at the bottom of the pot as a filter layer, then sprinkle a layer of fully decomposed organic fertilizer as a base fertilizer, about 1-2 cm thick, followed by a thin layer of matrix, about 1-2 cm thick, then place the plant to separate the fertilizer from the roots and avoid root burn. The matrix for potting can be one of the following: garden soil: furnace slag = 3:1; or garden soil: medium-coarse river sand: sawdust (straw residue) = 4:1:2; or one of the following: paddy soil, pond mud, decomposed leaf soil. After potting, water thoroughly and place in a shaded environment to care for one week. When transplanting young seedlings, dig a planting hole first, sprinkle a layer of organic fertilizer as a base fertilizer (bottom fertilizer) at the bottom of the planting hole, about 4-6 cm thick, then cover with soil and place the seedling, separating the fertilizer from the roots to avoid root burn. After placing the seedling, backfill the soil to cover the roots, press the soil with your feet, and water thoroughly.

Humidity Management: It prefers a humid climate environment and requires a relative humidity of 70-80% in the growing environment. If the relative humidity is too low, the lower leaves will turn yellow and fall off, and the upper leaves will lose their luster.

Temperature Management: As it is native to tropical regions, it prefers high temperature and humidity and is very strict about winter temperatures. It stops growing when the ambient temperature is below 10°C and cannot survive frost.

Light Management: It prefers a semi-shaded environment and can be given plenty of sunlight in autumn, winter, and spring, but should be shaded by more than 50% in summer. When kept indoors, it should be placed in a bright location, such as a living room, bedroom, study, etc. After being kept indoors for a period (about one month), it should be moved to a shaded (and heated in winter) outdoor area for a period (about one month) for alternate adjustment.

Fertilization and Water Management: For potted plants, in addition to adding organic fertilizer when potting, appropriate fertilization and water management should be carried out during the maintenance process.