Which month is best for sowing long beans without frames?

Many farmers grow beans by trellis cultivation, which is also a common method of growing beans. However, some beans do not require trellis cultivation. Frameless beans are one of them. It not only saves labor, effort and cost, but is also simple and easy to grow. So, which month is best for sowing frameless beans? Let’s take a look below.

1. Which month is best for sowing long beans without frames?

String beans are suitable for sowing in spring or summer. Sowing in spring can take advantage of lower temperatures and humidity, which is conducive to seed germination and growth. Sowing in summer can take advantage of higher temperatures and sunlight, which is beneficial to plant growth and fruiting. In addition, frameless long beans have low soil requirements, strong adaptability, and are suitable for planting in most areas.

2. Frameless bean cultivation technology

1. Land preparation and fertilization

It is advisable to choose sandy loam or slightly acidic soil with a thick tillage layer, loose soil, high organic matter content, and fields where no leguminous crops have been planted for more than two years. If the soil pH is lower than 5.5, lime should be applied to neutralize the acidity, which is conducive to the growth of beans. After deep plowing and land preparation, apply 1,500 kg of organic fertilizer and soil fertilizer per mu, 30-50 kg of phosphate fertilizer, 10 kg of compound fertilizer and 15 kg of potash fertilizer. After mixing evenly, make high ridges, each ridge is 1.8-2.0 meters wide (including ditch), ridge height is 20-25 centimeters, and ditch depth is 30 centimeters. Sow seeds after one or two days of sun exposure.

2. Season selection

Green beans can be sown twice a year, with autumn sowing time from mid-July to early August (spring sowing, mid-to-late February to early April). The specific sowing period should take into account both not growing during the frost period and not flowering and pod forming during the hottest period. Because green beans are thermophilic plants, they are not frost-resistant or heat-resistant. The suitable temperature for their growth is 13-25℃, 20℃ is the best, and the best temperature for flowering and pod formation is 15-25℃. When the daytime temperature is 13℃, the growth almost stops when the nighttime temperature stops at 8℃. When the daytime temperature is 18℃ and the nighttime temperature is 13℃, flowering and harvesting are delayed. If the flowering period encounters a low temperature of 15℃, the number of seed pods and the number of grains per pod will decrease. Higher temperatures promote growth and development, the number of flower bud differentiation and the number of flowers increase accordingly, and the flowering period is also relatively advanced. However, if the temperature exceeds 30℃, flowers and pods will easily fall off, and the yield will decrease. Generally speaking, spring-sown beans are most afraid of repeated low temperatures or continuous rainy weather, which can easily cause seed rot and seedling death. If conditions permit, it is best to cover the soil with mulch.

3. Sowing and seedling raising

The surface of bean seeds is often covered with gray mold. Before sowing, you can soak the seeds in 500-1000 times diluted thiophanate-methyl for 15 minutes to prevent gray mold in the seedling stage; soak the seeds in 1% formalin for 20 minutes before planting to reduce the occurrence of anthracnose, then rinse with water before sowing, or mix the seeds with 0.3% of Furamosine before sowing, with a plant spacing of 30-35 cm, 1-2 seeds per nest, and about 2 kg of seeds per mu. When planting, the soil should not be too deep, otherwise it will be difficult for the seedlings to emerge and the seeds will rot easily. After sowing, water once or not depending on the dryness or wetness of the soil. The suitable temperature for germination of kidney bean seeds is 18-28℃, and the germination days are 3-4 days. When the temperature is low, the germination time is relatively extended, but the minimum value is not lower than 15℃. In addition, it is best to dry the seeds for 2-3 days before sowing, which can promote uniform germination and reduce the phenomenon of seed rot caused by sowing in low temperature periods.

4. Fertilizer and water management

Bean plants grow vigorously when the soil is moist. When it is too dry, they grow slowly, but when it is too wet, it can cause yellowing and shedding of the basal leaves or death of the plant. Therefore, water or drain in time. The demand for fertilizer increases significantly with flowering and pod setting. After flower bud differentiation, nitrogen promotes plant growth, increases the number of flowers, and produces more pods. However, if there is too much nitrogen fertilizer and water, the stems and leaves will grow too long, and the flowers and fruits will fall off. Therefore, topdressing depends on the growth potential. Generally, after the second pair of true leaves grow out, use 10% manure or 3-5kg of urea diluted with water and apply it; when the plants begin to clump, soak the triple compound fertilizer in water and then dilute it with water and apply it once. The amount of fertilizer used per mu is 6-9kg, and the amount of nitrogen fertilizer applied should be controlled. At the same time, less watering should be done in spring to prevent cold waves. When the seeds begin to bloom and form pods, apply compound fertilizer twice, 12-15 kg each time.

5. Flowering period management

Flower bud differentiation of kidney beans begins from the seedling stage and usually begins 20-25 days after sowing. However, the flowering date is 35-40 days after sowing, and the accumulated temperature must reach 700-800℃ before it can actually bloom and pod (860-1150℃ for climbing species). The flowering period is about 12-19 days (about 25-44 days for climbing species). Before flowering, spraying the leaves and stem tops with 1500 times diluted Nongyou flowering essence or 5-25 mg/L gibberellin solution can promote flowering and increase pod setting; during the flowering period, spraying the inflorescences with 5-25 mg/L b-naphthaleneacetic acid solution or spraying the leaves with 0.3% potassium dihydrogen phosphate can help prevent flowers and pods from falling.

6. Harvest in time

Under normal circumstances, the young pods can be harvested 10-15 days after flowering, and 15-20 days when the temperature is low. The suitable harvesting period is when the pods change from flat to round, the color changes from green to light green, and the surface becomes shiny. Generally speaking, it takes about 50-55 days from sowing to harvesting of dwarf beans in autumn (55-65 days in spring), and the average yield per mu is around 1,000 kilograms.

That’s it