Soybean
Glycine max · Fabaceae
📷 Krzysztof Ziarnek, Kenraiz · CC BY-SA 4.0
The gardener's calendar
In autumn, ease off feeding and take the chance to clean up around soybean and prepare for winter.
ID card
- Foliage
- Deciduous
- Flowering
- July to September, small white or pale mauve flowers
- Adult size
- 24 to 32 inches in height
- Growth
- Fast
- Hardiness
- Annual, frost-tender
- Origin
- Southeast Asia (domesticated in China)
- Soil type
- Well-draining, fertile, slightly acidic to neutral
Expert tips
The key tip
Sème en mai-juin quand le sol est à 15°C minimum et reste ensuite stable : germination très lente et pourriture si tu presses trop tôt. Espacer les plants de 15-20 cm, arroser régulièrement mais pas en excès, car le soja est gourmand d'eau régulière pendant la floraison et la formation des gousses (juillet-septembre).
The common mistake
Semer trop tôt, dès avril : les graines pourrissent en sol froid et humide. La plupart des jardiniers considèrent mai trop tard, c'est l'inverse.
The pro's trick
Note les premières fleurs : dès qu'elles apparaissent, fais un apport d'engrais riche en potassium (ou utilise du purin de consoude). C'est le moment décisif pour le remplissage des gousses ; cette semaine-là fait toute la différence de rendement.
Seasonal watch
Août-septembre, surveille les acariens rouges et les aleurodes : chaleur sèche les attire. Brumise les plants ou arrose au pied le matin si tu vois des feuilles jaunes pointillistes.
Care
Watering
Water regularly to keep the soil moist but not waterlogged, especially during growth and flowering. Reduce watering after fruiting. Preferably use rainwater or non-calcareous water.
Light Exposure
Place your soybean in full sun, with a minimum of 6 to 8 hours of direct light daily. Good sunlight promotes vigorous growth and abundant fruiting.
Soil Preparation
Enrich the soil with well-decomposed compost before planting. Soybean appreciates fertile and well-structured soil. Ensure adequate drainage to prevent root rot.
Fertilizing
Apply a balanced fertilizer at the start of growth. As a legume, soybean fixes atmospheric nitrogen through root nodules, limiting additional nitrogen needs. Avoid excess nitrogen which would prolong vegetative growth.
Pruning and Training
No pruning is necessary. You can pinch off the top growing tip if the plant becomes too tall, to promote a more compact and branched shape.
Prevention and Problems
Monitor for pest attacks (aphids, spider mites) and fungal diseases in humid climates. Ensure good air circulation and avoid stagnant moisture. Aerated mulching limits infections at the base of the plant.
Did you know?
Soybean has been cultivated for over 3,000 years in Asia, initially in the northern Chinese provinces. Today, it represents one of the world's most important sources of protein and oil, and its cultivation has profoundly transformed global agriculture. In the West, soybean's culinary and cosmetic applications didn't really take off until the 20th century.
Where to buy it
Plant in spring or early autumn, avoiding spells of intense heat. Pick a plant with healthy foliage and roots that are not exposed. Best time: March, April, May, September.
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Tips generated and checked by Viridia — adapt them to your local climate.