Hemp
Cannabis sativa · Cannabaceae
📷 Roger McLassus. · CC BY-SA 3.0
The gardener's calendar
In autumn, ease off feeding and take the chance to clean up around hemp and prepare for winter.
ID card
- Foliage
- Deciduous
- Flowering
- Late summer to autumn
- Adult size
- 1 to 2 m in height depending on varieties
- Growth
- Very fast
- Hardiness
- Low hardiness, prefers temperate to warm climate
- Origin
- Central Asia
- Soil type
- Well-drained, fertile, slightly alkaline
Expert tips
The key tip
Le cannabis prospère avec 12-16 heures de lumière directe quotidienne en croissance, puis 12 heures d'obscurité continue pour forcer la floraison—sans tricher sur ce cycle, la plante stagne ou devient hermaphrodite. L'arrosage doit laisser le substrat sécher légèrement entre deux apports; les racines pourrissent rapidement en milieu saturé, surtout en phase de floraison où l'évaporation ralentit.
The common mistake
Arroser trop souvent et trop abondamment : c'est la cause numéro un d'échec. La plupart des cultivateurs noient leur plante par bonté, provoquant pourriture racinaire et maladies fongiques qui tuent avant la récolte.
The pro's trick
Utilisez la méthode du poids : soulevez le pot juste après arrosage, mémorisez ce poids, et ne réarrosez que quand il est devenu sensiblement plus léger. Cela élimine le doute et synchronise l'arrosage au véritable besoin de la plante, pas au calendrier.
Seasonal watch
En été, contrôlez activement la température (18-26°C optimal) : les températures prolongées au-delà de 28°C ralentissent la croissance et réduisent la production de résine; en hiver, une lumière insuffisante ou un froid excessif créent des plantes étiolées et faibles avant même la floraison.
Care
Watering
Keep the soil moist but not saturated. Water regularly during active growth period, especially during prolonged dry spells. Let the soil dry slightly between waterings to prevent root rot.
Light Exposure
This plant requires a minimum of 6 to 8 hours of direct sunlight daily for optimal growth. A south-facing exposure is ideal to maximize photosynthesis.
Soil Preparation
Prepare a substrate rich in organic matter, well-drained and slightly alkaline. Incorporate mature compost and ensure good aeration to promote root development.
Fertilization
Apply a balanced fertilizer during the vegetative growth phase, then switch to a phosphorus-rich formula during flowering. A monthly application is generally sufficient.
Pruning and Maintenance
Pruning is not essential but you can pinch the top to encourage denser branching. Remove lower or damaged leaves to improve air circulation.
Pests and Diseases
Watch for spider mites and whiteflies, particularly indoors. Powdery mildew can occur in humid conditions; ensure good ventilation and avoid excessive humidity.
Did you know?
Cannabis sativa has been cultivated for thousands of years in Asia, not only for its properties but also as a source of exceptionally resistant textile fibers. Ropes, sails and hemp-based fabrics equipped the greatest ancient civilizations and the ships of the modern era.
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.
Add this plant to my garden →Plants from the same family
- HopHumulus lupulus
- Nettle treeCeltis australis
- HackberryCeltis occidentalis
- Trema micranthumTrema micranthum
- Celtis laevigataCeltis laevigata
- Japanese hopHumulus scandens
Tips generated and checked by Viridia — adapt them to your local climate.