Introduction to green beans: varieties and characteristics
The green beans, also known as green beans or tender beans, belong to the genus phaseolus and represent one of the most appreciated horticultural crops, both in family gardens and in commercial farms, due to their Nutritional value, ease of cultivation and versatility in the kitchenThere are different species and varieties, the common bean being (Phaseolus) the most widespread, to which the scarlet bean is added (Phaseolus multiflorus) and the pinto bean (Phaseolus coccineus), each with its own characteristics in shape, size and color of pod or seed.
According to plant sizeGreen beans are divided into two main groups: short-stemmed, which usually reach 30-40 cm, and tall or climbing, stems that can reach 2-3 meters. The former are characterized by their shorter cycle and early maturity, while climbing beans are more productive and have a slightly longer cycle, allowing the harvest to be staggered to have tender beans throughout the growing season.
With regards to pod morphologyThere are varieties such as Sabinal (thick, flat pods), Garrafal (wide, flat pods in the center), and Boby (cylindrical or semi-cylindrical pods). The choice of the most suitable variety will depend on personal taste, environmental conditions, and the preferred cultivation system: greenhouse or outdoor.
When and how to plant green beans
La sowing green beans It should be programmed according to the soil temperature, since They require a minimum of 10ºC to germinateThey are sensitive to cold, and low temperatures can delay or prevent seedling emergence, so it's best to avoid sowing too early to protect them from possible late frosts. Staggered sowing is a recommended technique to ensure continuous production: resowing every 10-15 days allows for fresh harvests throughout the growing season.
To start growing, it is essential to use quality seeds and specifically selected for sowing, since dried beans purchased for consumption may germinate on rare occasions, but do not guarantee optimal development or the production of flowers and pods.
Sowing is usually done directly into the ground, placing one or two seeds per hole at a depth of 2-3 cm. It is advisable to leave a distance of 3-4 cm between seeds and adequate space between rows: 40-50 cm for dwarf beans and 70-80 cm for climbing beansAfter covering the seeds, lightly press down on the soil to ensure good contact and promote rapid germination.
To optimize root development and protect young seedlings, when the plants reach about 15 cm in height, it is recommended to carry out a hilled, that is, lightly mound soil around the base of the stem.
Land preparation and prior care
A suitable soil preparation It is key to successful cultivation, both in the greenhouse and outdoors. The soil should be loose, well-aerated, and well-drained to avoid waterlogging, one of the main obstacles to the development of green beans. A preliminary surface tillage, removing weeds and debris from previous crops, will reduce competition for nutrients and facilitate healthy growth.
It is important to make a bottom fertilizer Before sowing, incorporating well-decomposed organic matter (compost or cured manure) and avoiding excess nitrogen fertilizer, which can favor vegetative development to the detriment of flowering and pod formation, in addition to making the plants more vulnerable to pests and diseases.
In areas with nematode problems or soil diseases, it is recommended to consider the solarization or, in the case of intensive crops, steam sterilization and crop rotation to maintain subsoil health.
Sowing and tutors: techniques for optimal development
After sowing and once the seedlings have germinated and reached about 15 cm in height, it is time to place the tutors If a trellised variety is grown, staking promotes vertical growth and sun exposure, which translates into higher pod production and quality. Canes, hazel, chestnut, bamboo, or eucalyptus poles are often used, tying the top tips of the staking poles in parallel to form a stable, wind-resistant structure, similar to a tent.
If you prefer short-growing beans, staking is not necessary, but it is recommended to keep the soil free of weeds to prevent competition and improve aeration.
La germination The germination of green beans is rapid: under ideal conditions, the first leaves can be seen emerging in 7-10 days. During this phase, it is essential to protect the young seedlings from snails, slugs, and birds, using physical barriers or natural repellents.
El planting frame This should be followed according to the seed supplier's instructions. If the plants are too close together, ventilation and access to light will be limited, increasing the risk of fungal diseases.
Irrigation and water needs
The Green beans require balanced watering For optimal development, it's essential to keep the substrate slightly moist during the germination phase and early stages of growth, avoiding excess water, which can lead to rot or root suffocation. As the plant matures, watering frequency can be reduced, except during periods of high temperatures or drought.
It is preferable to localized or foot irrigation compared to sprinkler irrigation, since moisture on the leaves encourages the spread of diseases such as rust or powdery mildew. Irrigation should be gradually increased during the flowering and pod setting phases, subsequently adjusting according to the condition of the plants and the weather.
Ongoing care: weeding, defoliation and development control
To keep the crop healthy and productive, it is essential remove weeds regularly and, in the case of climbing varieties, guide the stems along the stakes as they grow. stripping of the oldest leaves It is recommended when the crop is well formed and there is abundant leaf mass, especially in times of high humidity, as it improves aeration and reduces the risk of disease.
La pruning The damage is usually minimal, but if damaged or pest-affected shoots are detected, it's advisable to remove them quickly. To extend the harvest period and improve the quality of your crop, pick the pods regularly, while they're still tender and before the seeds have fully developed inside the pod.
Main pests of green bean crops
Green beans can be affected by various pests, both in greenhouses and outdoors. Prevention and regular monitoring are the best strategies to avoid significant damage. The most common pests and their control methods are described below:
- Red spider (Tetranychus urticae): Causes discoloration, pitting, and yellow spots on leaves. Drying or defoliation can be severe if the pest progresses. High temperatures and low humidity favor its development. Biological control is effective using predatory mites such as Phytoseiulus persimilis o Amblyseius californicusFor chemical control, authorized products may be used.
- White spider (Polyphagotarsonemus latus): It primarily affects tender shoots, causing nerve curling and dwarfism. Chemical control and elimination of outbreaks are essential.
- White fly (Trialeurodes vaporariorum, Bemisia tabaci): It colonizes young parts of the plant and produces honeydew that promotes the growth of sooty mold. It is controlled with chromatic traps, biological control (introduction of encarsia formosa) and authorized products.
- caterpillars and worms (genres Spodoptera, Heliothis, Chrysodeixis): They cause damage to leaves, fruits and stems. The use of pheromones, light traps and biological treatments with Bacillus thuringiensis are effective methods.
- Aphid (Aphis gossypii, Myzus persicae): They form colonies on shoots and leaves, weakening the plant and transmitting viruses. Biological control with predators and parasitoids is a good option, along with color traps and specific products.
- Thrips, leaf miners and nematodes: They cause specific damage to leaves, stems, and roots, and can reduce vigor and production. The use of traps, soil management, and resistant varieties help keep the crop healthy.
Most common diseases in green beans
El phytosanitary management When growing green beans, special attention must be paid to fungal, bacterial, and viral diseases. The most common diseases and their prevention and control options are detailed below:
- Powdery mildew or ash (Sphaerotheca fuliginea): It appears as powdery white spots on leaves and stems. It is recommended to remove crop debris and apply sulfur-based treatments.
- Gray rot (Botrytis cinerea): It affects leaves, flowers, and fruits under high humidity conditions. Control is based on the removal of plant debris, adequate ventilation, and, if necessary, approved fungicides.
- White rot (Sclerotinia sclerotiorum): A disease that causes soft rot and white mycelium. Solarization and crop rotation are effective prevention methods.
- Roya (Uromyces phaseoli): Causes yellow and brown spots mainly on leaves. Proper ventilation and the use of copper-based products help keep the problem under control.
- Root and neck rot (Phytophthora spp., Pythium sp.): It is essential to avoid puddles and use healthy substrates, as well as disinfect tools.
- bacteriosis: Various bacteria (e.g., Xanthomonas campestris pv. phaseoli, Pseudomonas syringae) can cause wet spots, wilting, and lesions on leaves and stems. Using healthy seeds and removing diseased plants is crucial.
- VirusViruses such as common mosaic virus and yellow mosaic virus are transmitted by aphids and infected seeds. Controlling vectors and using certified seeds are the main preventive measures.
Ecological and integrated management of pests and diseases
El integrated pest control and diseases in green beans involves a combination of cultural practices, the use of natural enemies, and the rational use of phytosanitary products when necessary. It is recommended:
- practice the crop rotation and association with beneficial species.
- The use of chromatic traps to monitor pests such as whitefly and aphids.
- Regular introduction of auxiliary fauna as natural predators and parasitoids.
- Application of organic products, such as mineral oils or soap-based preparations, and phytosanitary products authorized for organic farming.
- Select resistant varieties to the main diseases to improve crop success and health.
Harvesting, post-harvest and conservation
The green beans They should be harvested at their optimum stage of development, when the pods are tender and stringless, preventing the seeds from developing excessively. Careful cutting encourages the emergence of new shoots and prolongs production. After harvesting, keep the beans in a cool, well-ventilated place. If you wish to store them, you can use the preserved, frozen or dehydrated depending on the final destination.
Advantages of greenhouse cultivation versus outdoor cultivation
El growing green beans in a greenhouse allows you to advance or prolong the campaign, protecting the plants from the cold, wind and excessive rain. In addition, by offering a stable microclimate, the incidence of pests and diseases associated with extreme conditions is reduced. Irrigation and nutrition can be more precisely controlled, leading to higher-quality and more consistent harvests.
However, the outdoor cultivation It offers the advantage of lower implementation costs and, in regions with a suitable climate, can offer optimal results with sustainable practices. The choice between the two systems will depend on your location, resources, and production goals.
