How to Grow Geraniums? Detailed Guide to Cultivation Methods and Precautions

Geranium, also known as hydrangea geranium or zonal geranium, is a perennial evergreen herbaceous or subshrub flowering plant in the family Geraniaceae, genus Pelargonium. It is native to southern Africa and widely cultivated around the world. Geraniums have a long flowering period, strong adaptability to the environment, a plant size suitable for home pot cultivation, and are easy to propagate, making them very popular. They are one of the common potted flowers in homes and also a commonly used flower for flower beds in warm winter regions. Geranium small flowers cluster together, and the large inflorescence resembles a hydrangea, with vivid colors. They can be used for indoor decoration and can also be arranged in spring flower beds and meeting venues. Below is a detailed introduction to how to grow geraniums:

1. Soil Selection for Geranium Cultivation

For potted geraniums, the growing medium can be made by mixing 4 parts humus soil, 3 parts garden soil (or peat soil), 2 parts river sand (or perlite), and 1 part organic fertilizer. It can also be prepared by mixing fine sandy soil, humus soil, perlite, and organic fertilizer. For potted geraniums, repotting is needed in autumn.

2. Fertilization Methods for Geranium Cultivation

During the growing period, apply liquid fertilizer once every 10-15 days. In spring and autumn, when growth is vigorous, apply liquid fertilizer once every 7-10 days. Before budding, nitrogen fertilizer should be dominant; after budding, phosphorus and potassium fertilizer should be dominant, with a concentration of 0.1%-0.2% being appropriate. If the indoor temperature in winter is relatively high and growth has not stopped, fertilizer should also be applied. During high summer temperatures, the plant is in a semi-dormant state and fertilization should be stopped. Because its stems and leaves have fine hairs, rinse immediately with clean water after fertilizing.

3. Watering Methods for Geranium Cultivation

Watering should be appropriate, preferring dry over wet. During the peak growing seasons of spring and autumn, sufficient water should be provided to keep the potting soil consistently moist, but not waterlogged. On cold cloudy days, generally do not water or fertilize. In summer, water less. In the north, the high-temperature season coincides with the rainy season. During this period, the plant's root system is relatively weak, so excessive rainwater irrigation should be avoided. Consecutive rainy days can cause root rot, so the plant should be placed in a shaded, cool, dry, and ventilated location. In winter, water according to indoor temperature; water less when room temperature is low, and more when room temperature is high. Geraniums have strong drought tolerance and will not die from drying out after several days without watering, but older leaves will turn yellow and fall off.

Watering should follow the principle of watering when dry and stopping when wet. Soil that is too wet easily causes root rot, while soil that is too dry easily causes leaves to turn yellow and wither. From June to July, the plant is in a semi-dormant state, and watering should be strictly controlled. In summer, spray water frequently to lower the temperature, keep the potting soil moist, and also pay attention to ventilation and light transmission. In winter, water sparingly.

4. Temperature Requirements for Geranium Cultivation

Geraniums prefer warmth, dislike high temperatures, and are afraid of cold. The suitable temperature for geranium growth is 15-25°C. In winter, the indoor temperature should be maintained at 10°C. Below 3°C, they are susceptible to cold damage, though some varieties can tolerate temperatures as low as 0°C. In summer, when the temperature exceeds 35°C, they enter a semi-dormant state.

5. Light Requirements for Geranium Cultivation

Under direct sunlight, they grow robustly, with dark green leaves, short internodes, and a beautiful plant shape. However, when summer light is too strong, 30%-50% shade is needed. For home cultivation, in autumn, winter, and spring, they should be placed in a location with direct sunlight. When flowering, they can be moved indoors for enjoyment, but after flowering they should still be placed in a lighted area. They prefer ample sunlight; when light is insufficient, they will not bloom. During the flowering period, direct strong light should be avoided; otherwise, the petals will scorch and easily fall off.

Rotate the pot once a week to ensure even light exposure on the leaf surface. Maintain a symmetrical plant shape. In summer, place in a cool location and avoid intense sun exposure. In winter, the room temperature should not be lower than 5°C, and provide ample light.

6. Pest and Disease Control for Geranium Cultivation

The main diseases of geraniums include mosaic disease, crinkle disease, chlorosis, gray mold disease, root rot, and bacterial wilt. The main pests include whiteflies, caterpillars, and small plume moths. For controlling mosaic disease, eliminating aphids is of great significance, and other nearby parasitic plants should also be cleared away. To control small plume moths, 90% trichlorfon at 1000 times dilution can be sprayed.

7. Precautions for Geranium Cultivation

(1) In order to control plant height and achieve the goal of large flowers and bright colors, in addition to selecting dwarf geranium varieties, the application of growth regulators is very important. Two weeks after geraniums are planted in 12 cm or 15 cm pots, 0.15% chlormequat or daminozide can be sprayed on the leaf surface once a week for 2 consecutive times, with 14-18 hours of light per day. This can effectively control the height of geraniums and provide high-quality commercial potted flowers.

(2) They are relatively tolerant of drought and afraid of waterlogging. Too much water easily causes plant death, and high temperature and high humidity easily cause root rot. They require well-drained, loose soil rich in organic matter. The flowering period is long, with the peak flowering period from April to June. If higher temperatures are provided in winter and management is proper, they can bloom continuously from September in autumn to June of the following year.

8. Propagation Methods for Geranium Cultivation

Geraniums are commonly propagated by seed sowing and cuttings, and can also be propagated by tissue culture.

(1) Seed propagation: Single-petal geranium varieties easily set seed, and seeds can be sown immediately after harvest. If sowing is to be delayed until the weather is cooler, the seeds can first be dried and stored in a paper bag. At 20°C, germination takes about 7-10 days. After seedling separation and transplanting, when the seedlings grow to 5-7 cm, they are planted into 10 cm pots and can bloom the following spring.

Because seedlings grown from seed have relatively poor plant characteristics and flowering quality, seed propagation is usually not used.

(2) Cutting propagation: Except from June to August when the plant is in a semi-dormant state, cuttings can be taken at any time. However, spring and autumn are best. Cuttings should preferably be taken from mother plants that bloom uniformly, bloom frequently, are true to variety, and are free of pests and diseases. Both the tender shoot tips and the lower tender stems can be used as cuttings, but the tip portion is best, with vigorous growth and fast rooting. After cutting the cuttings, soak them in 100 mg/kg indolebutyric acid for 5-10 seconds, then air-dry for half a day. After they wilt, insert them into a sand bed or a substrate mixed with perlite and peat at 1:1. After watering thoroughly, cover with a small arch shed, and provide shade when sunlight is strong. Maintain a temperature of 15-20°C. Roots form 2-3 weeks after insertion, and transplanting is done when roots are 3-4 cm long.

(3) Tissue culture propagation: Use MS medium, add 10 mg/kg indolebutyric acid and kinetin to promote callus and adventitious bud formation from explants, and use 100 mg/kg indolebutyric acid or indoleacetic acid to promote rooting. Tissue culture propagation is mainly used for elite seed propagation and new variety selection.

Geranium Cultivation Methods and Precautions

Geraniums are herbaceous and do not like too much water; they like sunlight. They remain green year-round, with little change through spring, summer, autumn, and winter. Geranium cultivation methods can be somewhat troublesome. Today we will take a look at geranium cultivation methods and precautions.

Control Temperature

The most suitable temperature for geranium growth is 10 to 20°C, which means spring and autumn are most suitable for geranium growth. Winter and summer are not very suitable, as winter is too cold and summer is too hot.

Control Water 

Because geraniums do not like too much water, be sure not to water excessively. If the roots of geraniums rot, it may be caused by overwatering and hot, stuffy weather. It is recommended to water once every two or three days. Each watering must be thorough.

Choose Soil 

The most suitable soil for geraniums is sandy soil. If you are worried about not growing them well, you can buy some soil at a flower market and mix in some sandy soil, which will give better results.

Pay Attention to the Effects of Bad Weather

Geraniums are most afraid of windy weather, because strong winds can break them. Also pay attention to heavy rain, because if there is a lot of rain, the roots of geraniums will be soaked in rainwater, and long-term soaking can lead to root rot.

Control Fertilization 

Do not apply too much fertilizer, otherwise geraniums will become dehydrated. The amount of fertilizer depends on the quality of the geranium soil, the size of the geranium pot, and the size of the geranium. Therefore, when buying flowers, it is recommended to ask the seller about the amount and frequency of fertilization. Too much fertilizer will cause geraniums to grow wildly without blooming.

Sufficient Sunlight 

To make geraniums bloom, there must be sufficient sunlight, but also be careful not to let the temperature get too high, because geraniums cannot be directly exposed to the sun. Therefore, it is recommended to give more sunlight in spring and autumn.

Geraniums are prone to leaf spot disease and wilt disease. If the leaf edges turn yellow and wither, consult a professional geranium seller. Be sure not to handle it casually.

Geranium Cultivation Methods and Precautions

Soil Selection for Geraniums

For geranium soil, you can choose a mixed growing medium of 4 parts humus soil, 3 parts garden soil (or peat soil), 2 parts river sand (or perlite), and 1 part organic fertilizer. It can also be prepared by mixing fine sandy soil, humus soil, perlite, and organic fertilizer. Geraniums require relatively loose and breathable soil. Repotting can be done every autumn, or the soil can be loosened in time.

Fertilization Methods for Geraniums

During the growing period, apply liquid fertilizer once every 10-15 days. In spring and autumn, during the vigorous growth period, apply liquid fertilizer once every 7-10 days. Before budding, nitrogen fertilizer should be dominant; after budding, phosphorus and potassium fertilizer should be dominant, with a concentration of 0.1%-0.2% being appropriate. In winter, if kept indoors with relatively high temperatures and growth basically does not stop, fertilizer can be applied appropriately. In summer, with high temperatures and the plant in a semi-dormant state, fertilization should be stopped. It is best to fertilize in the evening and water the next morning.

Watering Methods for Geraniums

Geraniums should be watered appropriately, preferring dry over wet. During the peak growing seasons of spring and autumn, sufficient water should be provided to keep the potting soil consistently moist, but not waterlogged. On cloudy or rainy days, generally do not water or fertilize. The plant can be allowed to receive some rainwater appropriately, but avoid excessive rainwater irrigation. Otherwise, it easily causes root rot.

In winter, water according to indoor temperature and try to use water at a suitable temperature to avoid yellowing of stems and leaves caused by water that is too cold. (For detailed watering techniques, see How to Water Geraniums)

Temperature Requirements for Geraniums

Geraniums prefer warmth, dislike high temperatures, and are afraid of cold. The suitable growth temperature for geraniums is 15-25°C. In winter, the indoor temperature should be maintained at 10°C. Below 3°C, they are susceptible to cold damage, though some varieties can tolerate temperatures as low as 0°C. In summer, when the temperature exceeds 35°C, they enter a semi-dormant state. Try to maintain ventilation and avoid a stuffy environment, which is not conducive to dormancy.

Light Requirements for Geraniums

Geraniums are not afraid of strong light, but they need shade at midday in summer. Under sunlight, geraniums grow robustly, with dark green leaves, short internodes, and a beautiful plant shape. For home cultivation, in autumn, winter, and spring, they should be placed in a location with direct sunlight. When flowering, they can be moved indoors for enjoyment and care, with appropriate light exposure, but direct strong light should be avoided to prevent petals from scorching.

Precautions for Geranium Cultivation

Geraniums have different varieties and plant heights. For home planting, small plants should be chosen. In addition, growth regulator application is also needed. When the plant grows to 12 cm or 15 cm, spray chlormequat once a week for 2 consecutive times. Ensure 14-18 hours of light per day. This can effectively control the height of geraniums and provide high-quality potted flowers.

Watering geraniums requires special attention, as too much can cause plant death, and high temperature and high humidity easily cause root rot. Of course, flowering time can also be controlled. The peak flowering period is generally from April to June, but if the temperature is appropriately raised in winter, they can bloom continuously from September in autumn to June of the following year.