Planting technology of large flower type new geranium

The plant height of large-flowered geranium 'Coral', 'Ice Cave' and 'Jingjing' ranges from 30 to 40cm, with round and large bouquets, good group planting effect and less diseases and insect pests, so they are good materials for landscape application. This kind of geraniums are all award-winning varieties in the European flower selection competition.

Growth habit

It likes cold and cool climate, and the suitable growth temperature is 5 ℃ ~ 25 ℃. The plant enters a semi-dormant state during the high temperature period in summer and can survive the winter with a little protection in cold areas in winter. Like the environment with sufficient light, tolerance to dryness, avoid water and dampness, the cultivation substrate is required to be loose, well drained and rich in organic matter.

Sow from late winter to early spring, and the flowering period runs through the whole summer. Sowing at the end of summer and overwintering temperature above 5 ℃ can blossom in spring.

Sowing method

Seeds should be seeded with thick 3~5mm matrix or 2~4mm thick coarse vermiculite to avoid light during germination. Sowing can use a 128-hole hole plate, the substrate uses imported peat, adding 10% diameter 3~5mm large-grained perlite, keep the substrate moderately moist, should not be too wet, 5 to 10 days to sprout.

Seedling management

The seedling raising period is 5 to 6 weeks, which is divided into four stages. In the first stage, from sowing to the emergence of the radicle, and in the second stage, from the appearance of the radicle to the extension of the cotyledons, the germination is completed and a true leaf grows. After emergence, it is necessary to reduce the humidity of the substrate, which is conducive to root development. In the third stage, a true leaf appears and begins to grow, reaching the transplanting standard. The fourth stage is to prepare for transplantation or storage and transportation. The germination temperature of the first stage is 21 ℃ ~ 24 ℃, which takes 3 to 5 days, and the substrate should be moderately moist. The temperature of the second stage is 21 ℃ ~ 24 ℃, which can be fertilized once a week. The N ∶ P ∶ K fertilizer is 15 ∶ 0 ∶ 15 and 20 ∶ 10 ∶ 20 alternately, the concentration is 50~75ppm, it takes 5 to 10 days, and the substrate is moderately moist. In the third stage, the temperature is 18 ℃ ~ 21 ℃, the concentration of fertilizer is 100~150ppm, and it takes 14 to 21 days to apply fertilizer twice a week. The temperature of the fourth stage is 17 ℃ ~ 18 ℃, which takes 7 days, and the fertilization concentration is the same as that of the third stage, and then it can be planted in the basin of 14cm × 12cm.

The pH value of pH water should be adjusted to slightly acidic, and the pH value of matrix should be controlled at 6.2-6.5.

During the whole seedling period, the substrate temperature should not be lower than 18 ℃. Too low temperature hinders the growth and development of seedlings.

Light seedlings should be exposed to light quickly after germination to prevent overgrowth. During the seedling period, the light can be maintained for 16 to 18 hours a day for 4 weeks, and the light intensity is 3200~5400lux. Geraniums like light, the more light, the more light, the fertilizer for growth is Meiwo imported from the United States, N ∶ P ∶ K is 20 ∶ 10 ∶ 20. 0.5 g of this fertilizer should be added per liter of water to obtain 100ppm, and other concentrations should be adjusted accordingly. If Meiwo N ∶ P ∶ K is 15 ∶ 0 ∶ 15, 0.67g of this fertilizer should be added per liter of water to obtain 100ppm fertilizer, and other concentrations should be adjusted accordingly.

Moisture keeps the substrate moderately moist, and keeps the substrate dry between two watering times, while keeping low air humidity to reduce the occurrence of diseases. If the concentration of chlorine in the substrate exceeds 1ppm, it may cause toxicity to cotyledons and produce immature leaves, so care should be taken to avoid using tap water with high chlorine content.

After the growth of cotyledons for pest control, 1000 times liquid chlorothalonil or methyl topiramate was sprayed every week to prevent quenching disease and sprayed 2 to 3 times continuously.

Seedling stage management

The upper basin substrate can be mixed with peat and garden soil according to the ratio of 1 ∶ 1, and the effect of adding a certain amount of organic fertilizer is better. Immediately after planting, 1000 times solution of methyl topiramate was applied to fix roots, which could prevent the occurrence of root rot. The plant shape can be plump without picking the heart during cultivation.

The light keeps the growth environment in a full-day state to make it grow well and blossom as soon as possible; making use of the characteristics that geranium flowering needs to accumulate a certain amount of light, the flowering period can be adjusted by adjusting light, and the specific operation must be carried out according to the actual growth status of the plant.

The temperature of pelargonium likes cool environment and is afraid of high temperature. the suitable temperature for growth is 5 ℃ ~ 25 ℃, and it is the most suitable for growth in spring. When cultivated in autumn and winter, the night temperature is not less than 5 ℃, so the geranium needs greenhouse or greenhouse protection in the north, otherwise it is vulnerable to freezing injury. In winter, the indoor temperature is not less than 10 ℃ in daytime and 5 ℃ at night, which can blossom continuously. The summer weather in southern China is hot, and the growth of geranium is in a semi-dormant state with poor flowering. During this period, the temperature should be properly reduced to below 30 ℃ to make it safe to pass the summer. When the temperature drops in autumn, sufficient water and fertilizer will be supplied to make the branches blossom. The leaves of geranium have high ornamental value. Picking off the withered and yellow leaves and residual flowers at any time and topdressing them at the right time can promote the second flowering and prolong the ornamental period.

Keep the substrate moderately moist in the process of water growth. Geranium is not resistant to water and moisture, which requires good ventilation of the cultivation substrate, otherwise the proportion of rhizome is easy to be maladjusted. Too much water is prone to root rot and gray mold caused by fungi, but the cultivation substrate should not be too dry, otherwise salt will accumulate around the root system and cause burning. When the substrate is too dry, it often turns the lower leaves of the plant into reddish to yellow. The stems and leaves of pelargonium are pilose. When fertilizing and watering, the leaves should be avoided from being contaminated with fertilizer and water. Wash the leaves with clean water and dry them after fertilization.

The compound fertilizer with N ∶ P ∶ K of 15 ∶ 20 ∶ 20 could be applied 7 days after fertilization and planting, once every 7 to 10 days. Fertilizers containing potassium, calcium nitrate and phosphorus were used in the growth process. Geraniums are very sensitive to ammonium groups, and the concentration of these fertilizers should not exceed 10ppm, but in warm areas, when the light is strong, it may be necessary to apply N ∶ P ∶ K 20 ∶ 10 ∶ 20 fertilizer to make the leaves stretch and color well.

Disease prevention and cure

(1) Gray mold

a. Main symptoms: mainly damage to leaves and flowers. Leaf vein primary "V"-shaped disease spot, on which there are nearly round to irregular water-stained yellow-brown to dark brown round spots, and sometimes produce a gray-white mildew layer. When the disease occurs on the petals, it is faded, irregular, sparse gray mold occurs at the beginning, the gray mold shrinks when the weather is fine or dry, and breeds again when wet, and the flowers become dark red to dark brown.

b. Prevention and treatment: pay attention to the ventilation and light transmission of the cultivation place, and the humidity should not be too high. At the initial stage of the disease, the whole plant was sprayed with 1000-fold solution of 50% prohydantoin or 28% Botrytis cinerea 800-1000 times.

(2) Brown shift disease

a. The main symptoms: mostly occur on the leaves, for round, near-round to irregular-shaped disease spot, the disease spot is light brown or grayish white to reddish brown, with dark brown edge. The leaf back disease spot is slightly convex, the outer edge of the spot yellow halo is obvious, the disease spot often fuses with each other into a larger dead spot, and finally produces gray-black mildew on both sides.

b. Control methods: keep the cultivation place ventilated and transparent, control fertilizer and water during the dormant period, and should not apply too much. At the initial stage of the disease, 75% methyl topiramate was sprayed with 1000 times of carbendazim or 50% carbendazim or 1000 times carbendazim, once every 10 days for 2 to 3 consecutive times.

(3) bacterial leaf spot

a. The main symptoms: the leaves appeared watery round to irregular sunken spots, dark brown to dark brown, the disease spots were less fused, and in the later stage, the diseased leaves wilted and curled and hung on the stem, and sometimes the disease spots formed large necrotic horn spots on the leaf edge. Black plaques were produced on the stem, and the vascular bundles and pith blackened, and the plant wilted and rotted.

b. Prevention and control methods: watering and fertilization try to avoid the cultivation substrate spilling on the stems and leaves, and control the substrate and air humidity not to be too high. Chemical control with 53.8% can kill 1000 times of 2000 dry suspension or 72% of agricultural streptomycin 2000 times of spraying the whole plant.