How to grow African violets? A detailed explanation of key cultivation techniques

For the potting medium, use a medium made from high-quality sphagnum peat moss. It is light in texture, well-draining, and fertile, making it most suitable for the growth and development of African violets. The pH of the medium is 5--6.

As for pot size, for the standard size of African violets, 9 cm pots are commonly used. For large-crown varieties, 10--12 cm pots are recommended.

For potting and planting, to make handling easier and reduce damage to the plants, water sparingly after planting, just enough to keep it moist. When planting, be careful not to press the potting soil too firmly; keep it loose. According to the growth habits of African violets, the plants should not be planted too deep or too shallow. If too deep, the crown leaves will be buried; if too shallow, the plant will easily topple. The correct standard is that after watering, the crown leaves are level with the potting soil.

Spacing out: After 5--6 weeks of entering the growth period, the leaves of African violets begin to crowd together, which requires spacing out. Usually this is done only once. For 9 cm pots, generally 40--45 pots are placed per square meter. If spaced out too early, the plants' microclimate will not exist, causing slowed growth, stunted plants, and even delayed flowering. If this situation occurs, try dividing the spacing into 2 times: the first time, place 55--60 pots per square meter; when the leaves crowd together again, carry out the second spacing out, placing 40--45 pots per square meter.

Watering: The water temperature is very important. The water temperature must not differ from the air temperature by 5°C, otherwise yellow spots are likely to appear on the leaves. Water immediately after the seedlings are planted. Before the first spacing out, watering can be done from the top of the plants. Afterward, this method should be changed, otherwise it will damage the flower buds. Just after the seedlings are planted, do not water with fertilizer solution; only water with clear water.

Temperature: The growing air temperature is 20--21°C, the day-night temperature difference must not be greater than 1°C, and the soil temperature should be kept at 18°C.

Shading: The suitable light range is 10000--12000 lux. How much shade to provide should follow this simple rule: on a clear day, you will clearly see the shadow of your outstretched palm on the leaves. Observation should be carried out persistently, because even a brief period of excessive exposure can lead to serious consequences. Therefore, from late February to early March, although there is indoor shading, the temperature and light in the greenhouse rise too quickly in summer, so a shading coating needs to be sprayed on the glass.

Light: From October to March of the following year, artificial supplemental lighting can shorten the growth period by 2 weeks. It is recommended to use a fluorescent lamp with a light intensity of 2750 lux, illuminated for 14 hours a day. Stop supplemental lighting when natural light exceeds 2750 lux.

Carbon dioxide fertilization: From sunrise to sunset, keep the carbon dioxide concentration at (500--600)×10(to the negative 6th power). On sunny days or under artificial supplemental lighting, the carbon dioxide concentration should preferably be kept at (700--800)×10(to the negative 6th power). When the carbon dioxide concentration exceeds 1000×10(to the negative 6th power), the plants will be harmed. Carbon dioxide fertilization cannot be carried out at night.