Evening Primrose Planting Techniques and Cultivation Methods Explained in Detail
Evening primrose is an erect biennial coarse herbaceous plant of the genus Oenothera in the family Onagraceae, also known as evening star, sundrops, mountain sesame, wild sesame, etc. It is native to North America and was introduced to Europe early on, then spread rapidly to temperate and subtropical regions worldwide. In Northeast China, North China, East China and Southwest China it is cultivated and has long since become naturalized. Let us take a look at evening primrose planting techniques together below!
Evening Primrose Planting Environment
Evening primrose has strong adaptability, tolerates acid and drought, and is not demanding about soil. It can generally grow in neutral, slightly alkaline or slightly acidic soil that is well-drained and loose, but in places where the soil is too wet the roots are prone to disease. In the north it is an annual plant, and south of the Huai River it is a biennial plant. It often grows on open barren slopes and roadsides, tolerates drought and poor soil, and is suitable for planting in black soil, sandy soil, loess, young forest land, mildly saline-alkali land, wasteland, river beach land and hillside land.
Evening Primrose Seed Propagation
Evening primrose can be sown in both spring and autumn. The autumn sowing period is from mid-October to before the ground freezes. If there is heavy winter snow, autumn sowing is better than spring sowing; if there is little winter snow, it easily causes missing plants and broken rows. Spring sowing can be done before wheat sowing, when the soil has thawed 2-3 cm. Because the sowing rate is low, use 60 kg of diammonium phosphate per hectare as a filler for seed dressing; if insufficient, a certain amount of dry sawdust or roasted wheat, rapeseed, etc. can be added for sowing. Sow at a depth of 1-2 cm, and press the soil promptly after sowing. The seed rate is 6 kg per hectare, with 400,000-500,000 plants retained per hectare. The density at sowing must not be too low, otherwise branching will occur and the maturity period will be uneven.
Evening Primrose Cutting Techniques
1. Cutting wood for cuttings: The branches used for evening primrose cuttings are called cuttings. Usually combined with pinching work, the thick, pest- and disease-free top shoots that are pinched off are used as cuttings. The optimum temperature for cutting rooting is 18-25°C. Below 18°C, the cuttings root with difficulty and slowly; above 25°C, the cut surface of the cuttings is easily infected by pathogens and rots, and the higher the temperature, the greater the proportion of rot.
2. Temperature management: When low temperatures are encountered after cutting, the main measure for insulation is to wrap the flower pot or container used for cuttings with film. When the temperature is too high after cutting, the main cooling measure is to shade the cuttings, blocking out 50-80% of sunlight, and at the same time spray the cuttings, 3-5 times a day. On sunny days with higher temperatures, spray more times; on cloudy and rainy days with lower temperatures and higher humidity, spray fewer times or not at all.
3. Humidity management: After cutting, the relative air humidity must be maintained at 75-85%. Humidity can be increased by spraying the cuttings, 1-3 times a day. On sunny days, the higher the temperature, the more times to spray; on cloudy and rainy days, the lower the temperature, the fewer times to spray or not to spray. However, excessive spraying makes the cuttings easily infected by pathogens and rotted, because many kinds of pathogens exist in water.
4. Light management: Cutting propagation cannot do without sunlight, but the stronger the light, the higher the temperature inside the cuttings, the more vigorous the transpiration of the cuttings, and the more water consumed, which is not conducive to the survival of the cuttings. Therefore, after cutting, 50-80% of sunlight must be blocked. After the root system grows out, gradually remove the shade net. On sunny days, remove the shade net at 4:00 p.m. each day and cover it again before 9:00 a.m. the next day.
Evening Primrose Planting Techniques
1. Land selection and preparation: Evening primrose is strong-growing, cold-tolerant, drought-tolerant, barren-tolerant, likes sunlight and avoids waterlogging. It should be planted on fertile, well-drained land following soybean or melon crops. Continuous cropping is possible, but land with residues of herbicides such as chlorsulfuron, chlorimuron-ethyl, Pursuit and Command cannot be used to plant evening primrose. For land preparation, soybean stubble and mixed stubble can be directly harrowed and ridged in autumn.
2. Potting substrate: The substrate used for potting can be one of the following: vegetable garden soil + furnace slag = 3 parts + 1 part, or garden soil + medium-coarse river sand + sawdust (mushroom residue) = 4 parts + 1 part + 2 parts, or peat + perlite + ceramsite = 2 parts + 2 parts + 1 part, or vegetable garden soil + furnace slag = 3 parts + 1 part, or peat + furnace slag + ceramsite = 2 parts + 2 parts + 1 part, or sawdust + vermiculite + medium-coarse river sand = 2 parts + 2 parts + 1 part.
3. Potting seedlings: When potting seedlings, first place coarse-grained substrate or ceramsite 2-3 cm thick at the bottom of the pot as a drainage layer, sprinkle a layer of fully decomposed organic fertilizer on top as base fertilizer, about 1-2 cm thick, then cover with another layer of substrate about 1-2 cm thick, and then place the plant in, so as to separate the fertilizer from the root system and avoid burning the roots. After potting, water thoroughly once and keep in a slightly shaded environment for a week of care.
4. Transplanting seedlings: When transplanting seedlings, first dig the planting hole, sprinkle a layer of organic fertilizer at the bottom of the planting hole as bottom fertilizer (base fertilizer), about 4-6 cm thick, then cover with a layer of soil and place the seedling in, so as to separate the fertilizer from the root system and avoid burning the roots. After placing the seedling in, backfill the soil to cover the root system, tread the soil firm with your feet, and water thoroughly once.
5. Field management: Before the second pair of true leaves unfolds, the seedlings are very similar to weed seedlings and easily confused, so hoeing and weeding cannot be carried out at this time; it can only be done after the second pair of true leaves unfolds. When the seedlings grow to 5-6 leaves and there are many grass weeds, haloxyfop and quizalofop-p can be sprayed to kill the weeds. During the growth period, 2 rounds of hoeing and 2 times of intertillage should be carried out. The hoeing and ridging must be finished before flowering. When the seedlings cover the rows, carry out the first round of hoeing and intertillage. In late July and early August, carry out 2 times of manual pulling of large weeds, so that there are no weeds in the field taller than the evening primrose plants.
6. Harvesting and processing: Evening primrose has an indeterminate inflorescence, and the fruits mature successively. Generally, when 3-4 basal pods turn yellow and are about to split, it is the best harvest period, specifically in mid-to-late September. If later, the early-maturing fruits will have dried and split, and the seeds will scatter on their own. It can be cut and sun-dried manually or with a swather. After drying for 5-7 days, use a combine harvester to pick up the grain or thresh manually (by beating). The harvested seeds are graded and cleaned with a grain cleaner to remove impurities, and after drying until the moisture content drops below 11%, they are bagged for storage or sale.