How to grow geraniums? Learn cultivation techniques with me (Part 1)

Geranium is a perennial herbaceous plant, subshrub-like, fond of cool climates, with a suitable growth temperature of 5°C-25°C; seeds germinate better at 21°C-20°C. It is not heat-tolerant, and the plant enters a semi-dormant state during the high-temperature period in summer. It likes to grow in an environment with sufficient light, is tolerant of dryness, and dislikes waterlogging; the growing medium is required to be loose and well-drained, rich in organic matter.

I. Sowing and seedling raising

1. Sowing time in southern regions: open-field sowing period February-March, September-October, open-field flowering period February-June, October-December; greenhouse sowing period January-March, September-December, greenhouse flowering period January-June, October-December; glasshouse sowing period January-March, September-December, glasshouse flowering period January-June, October-December.

2. Sowing conditions

① Seedling medium: use the special flower seedling medium "Zhuangmiao No. 3".

② Light: seeds germinate in darkness, so after sowing cover with 0.3cm of medium.

③ Temperature: keep the medium temperature at 21°C-25°C; seedlings emerge in 5-10 days.

④ Humidity: after sowing, keep the medium at moderate humidity; it should not be too wet.

⑤ Sowing method: direct sowing in plug trays or drilling in seedling trays.

II. Seedling-stage management

1. Temperature. Keep the medium temperature at 21°C-25°C; seedlings emerge in 5-10 days. Too high a temperature easily causes seeds to enter heat dormancy and affects germination, while too low a temperature hinders the growth and development of seedlings. Throughout the seedling-raising period, the medium temperature should be kept no lower than 18°C. Keep the pH value between 6.0-7.0; the most suitable growth pH value for geranium is 6.2-6.5.

Light. After the seedlings germinate, they should quickly receive light to prevent leggy growth; during the seedling-raising period, light can be maintained at 16-18 hours per day for 4 weeks, with a light intensity of 3200-5400 Lux; geranium is called a "light accumulator", meaning that the more light accumulated, the faster it grows and blooms.

2. Fertilizer. When direct sowing in plug trays, after the cotyledons are fully flattened, apply a 1000-times solution of "Yelüjing" as a top dressing once a week; before planting, the concentration can be increased to an 800-times solution; when using other fertilizers, if the chlorine concentration exceeds 1ppm, it may cause phytotoxicity to the cotyledons; at the same time, care should be taken to avoid using tap water with excessively high chlorine content.

Water. Keep the medium at moderate humidity, and the medium should remain dry between two waterings; at the same time, keep air humidity low to reduce the occurrence of diseases.

III. Cultivation management

Transplanting. For those raised by drilling in seedling trays, when the seedling cotyledons are fully flattened, they can be pricked out into 70-cell plug trays; after about 20 days, when the seedlings have 4-5 true leaves, they can be planted into pots. Immediately after planting, water with a 1000-times solution of thiophanate-methyl as the "root-setting water" to prevent the occurrence of root rot (Pythium).

Temperature. Geranium likes a cool growing environment and fears high temperatures; the suitable growth temperature is 5°C-25°C, and spring is the most suitable for growth. When cultivating in autumn and winter, the night temperature should not be lower than 5°C; therefore, in the north geraniums need to be protected in a glasshouse or greenhouse, otherwise they are prone to cold damage; in the south, summer weather is hot, and geranium growth is in a semi-dormant state with poor flowering; during this period, moderate cooling is needed to below 30°C so that they can safely pass the summer.

Light. Keep the growing environment in full sun so that they grow well and bloom as early as possible; by making use of the characteristic that geranium flowering requires a certain accumulation of light, light can be adjusted to regulate their flowering period, according to the actual growth condition.