Rosmarinus Planting Environment Requirements
Information about the planting environment requirements, planting methods, and precautions for rosemary will be introduced comprehensively next.
Rosemary, also known as incense weed or oil grass. The young stems and leaves of rosemary can be used for salads, stewed dishes, soups, and as seasoning for vegetables like potatoes, fish, poultry, and meat. Its aroma remains even after long cooking, has a good effect on removing fishy smells, and is considered a high-end Western cuisine spice. Its strong fragrance has a calming effect and can make people feel joyful. Chewing the leaves can also eliminate bad breath. Rosemary is an essential component in many mixed spices. In Italian and French cuisine, rosemary is also a commonly used spice, such as being indispensable in the cooking of Italian lamb. The dried rosemary has a stronger aroma than the fresh stems and leaves but fresh ones are more often used in Mediterranean-style dishes. Rosemary can also enhance the flavor of vinegar.
☞ Growing Environment Requirements:
Rosemary is native to the Mediterranean region and prefers a cool summer, no severe cold in winter, and large temperature differences between day and night.
It requires a warm and humid climate, with a suitable growth temperature of 15-30°C. Generally, it will die if the temperature is below -5°C for 5 consecutive days in winter, and the plant will enter summer dormancy when the temperature exceeds 35°C in summer. However, some varieties introduced in China can tolerate temperatures as low as -10°C.
It is a long-day plant and requires more than 2,000 hours of sunlight throughout the year. Insufficient light will affect the content and quality of essential oils and antioxidants.
It is not tolerant to waterlogging and requires well-drained soil. Excessively wet soil can cause defoliation and root rot, and high humidity can lead to severe seedling death.
It is not strict about soil requirements and can grow well in slightly acidic or alkaline soil. It is耐贫瘠 and can grow normally on hilly and stony soils, but a well-drained, loose, and fertile slightly alkaline sandy loam is preferred.
It can be harvested continuously for many years after one planting, flowering twice a year, from late April to mid-May and from late August to mid-September, with a flowering period of about one month. The seed setting rate is low, and the seeds have a low maturity and are not easy to germinate.
☞ Key Cultivation Techniques:
1. Main Cultivation Season
In regions such as Henan, Hunan, and Yunnan, open-field cutting of seedlings is planted from late March to mid-April, and the aromatic oil is distilled twice in July and October. In warmer southern regions, it can overwinter in the open field, while in the Beijing area, it needs to be covered with soil for frost prevention and is best kept in a greenhouse or sunken bed for overwintering. After one planting, it can be harvested for many years.
2. Field Preparation
A plot with loose and fertile soil, thick soil layer, rich in organic matter, and high and dry terrain, with good drainage, should be selected. Weeds should be removed, and the soil should be plowed to a depth of 25-30 cm. Apply 3,000 kg of decomposed organic fertilizer, 50 kg of compound fertilizer, 20 kg of superphosphate, and 80 kg of lime per 667 square meters as a base fertilizer. Make ridges with a width of 1.5-2.0 meters and ditches 30 cm wide and 20-30 cm deep.
3. Seedling Preparation
Rosemary can be propagated by seeds, cuttings, or layering. However, the seedling rate is low, the growth is slow in the first year with significant variation, and the layering method has a low propagation rate. The cutting method is commonly used in production.
① Cutting Propagation: The timing can be from September to the following March, but it is better to do it in late autumn and early winter. Choose a vegetable seedling bed with loose and fertile soil and convenient irrigation. The ridge width should be 1 meter, and the ditch depth should be 30 cm. Select strong one-year-old semi-woody branches from the mother plant as cuttings. The cuttings should have a growth point, about 10-15 cm long, with more than 6 pairs of leaves, and soaked in a rooting powder solution for 24 hours. The spacing between cuttings should be 5 cm, row spacing 12 cm, and the depth of cutting should be 3-5 cm. After cutting, press the soil manually and water thoroughly. It is advisable to cover with a sunshade net at noon in the early stage, water 1-2 times a week to keep the soil moist, and pay attention to insulation and frost prevention during the overwintering period. Cutting seedlings in late autumn and winter should be carried out in facilities such as a solar greenhouse or plastic greenhouse, with a room temperature of 16-20°C for 20-30 days to root. After the following spring, foliar spray 0.5% urea and potassium dihydrogen phosphate solution 2-3 times. One week before transplanting, harden the seedlings and apply a 1% urea solution externally.
② Layering Propagation: Roots quickly, suitable for propagating large seedlings. The method is to dig a 5 cm deep circular trench around the base of the plant, bend the middle of the branch into the trench, cover it with 5 cm of soil, and water to keep the soil moist. This can be done all year round in most regions.
4. Field Planting
The suitable time for field planting in the Yangtze River Valley is from late March to mid-April. Plant with soil, with a spacing of 30 cm between plants and 50 cm between rows, 1 plant per hole, and water after planting.
5. Field Management
The focus of rosemary field management is irrigation. Excessive drought or humidity in the soil can easily lead to plant death. It is necessary to dig good ditches, waist ditches, and surrounding ditches to ensure smooth drainage.
① Watering and Fertilizing: Water in time after transplanting to keep the soil moist. 30 days after transplanting, apply 1,000 kg of decomposed human manure or 10-15 kg of urea per 667 square meters; thereafter, fertilize every 30 days, applying 10-15 kg of urea and 15-20 kg of compound fertilizer per 667 square meters each time. During the growth of the plant, it is necessary to cultivate and weed frequently.
② Pruning and Pinching: In order to ensure the healthy growth of the plant, pruning and pinching should also be done to keep the plants ventilated and ensure the growth and yield. Generally, dense branches in the lower part and inside of the plant should be cut first. A round canopy shape is best for pruning. After flowering, rosemary affects its own growth and utility value, so it should be controlled to bloom less or not at all, especially the flowers in the first year should be pinched in time.
In winter facility cultivation, the daytime temperature should be 20-25°C and the night temperature should be 10-15°C; the light intensity should not be lower than 85% of that in the open field.
③ Pest and Disease Control: Rosemary has few pests and diseases. At high humidity, some plants may be infected with fungal diseases, such as powdery mildew in facility cultivation, which should be prevented. Powdery mildew can be controlled with a 20% triazole copper emulsion at a concentration of 2,000 times. The main pests are aphids and whiteflies, which can be controlled with a 5%扑虱蚜 solution at 2,500 times and a 1.5% abamectin solution at 3,000 times.
6. Harvesting and Processing
① Harvesting: For culinary purposes, mainly harvest the young stems and leaves, which can be harvested when the main stem is 40-50 cm long, about every 20-30 days. It can be harvested all year round in the south, and in the north, it can also be supplied all year round with protected cultivation, but the yield and quality are highest from April to August. The length of the young stems for harvesting is about 10 cm, with a yield of 1,000 kg per 667 square meters. When using rosemary as a seasoning, it should not be used in excess, a little is enough.
② Processing: For the purpose of steam-extracting essential oils, the products are leaves and flowers, which can be harvested at any season, but the quality of oil is better during the flowering period, generally harvested in July and October, with 400 kg of raw materials harvested per 667 square meters each time. The branches pruned can be used for seedling or for extracting rosemary essential oils.
The above is a specific introduction to the planting environment requirements, planting methods, and precautions for rosemary, for reference by netizens.