By Albert Makendenge
Hemp, just like marijuana, is basically a hardy leguminous flowering cannabis plant in the Cannabaceae family. The only difference is while hemp contains 0.3 percent or less of the tetrahydrocannabinol (THC –) content by dry weight and is taller, marijuana, which is shorter, contains much higher amounts of the cannabinoids or THC chemical. Given its various commercial/industrial and subsistence uses in food and beverages, clothing, paper, pet food and animal bedding, construction materials, plastic, fuel, soaps and skincare products, chemical clean up, livestock feed and so much more, hemp is rapidly gaining recognition across the globe. Zimbabwe recently gave the go ahead to grow this highly rated plant and multi-purpose plant and thus farmers would be interested to know, as laid out below, the tips and tricks to growing it right. Growing it only after acquiring a permit from the responsible authorities which is a requirement for anyone growing, researching or dealing in mbanje.
Industrial hemp production starts off with the knowledge of what kind to grow from the two most common distinct segments which are seed/fibre and cannabinol (CBD). The approach to growing these two differs with planting populations of up to 600 000 to 800 000 plants per hectare (roughly 100 plants per square meter) for seed/fibre and planting populations of about 3000 to 4000 plants per hectare. For the seed/fibre plants that typically grow tall, it is the tops are harvested for seed production and the stalk for fibre whilst for CBD plants, only the flowers which have the highest concentration of the chemical are harvested and dried before the extraction process.
- While hemp can grow anywhere in the world except the extreme and unfavorable cold climates, it grows best when the outdoor temperature is between 16 degrees Celsius to 27 degrees Celsius and should be planted after the last days of frost (usually between September, November and December in the southern hemisphere.
- Moist, well drained and aerated loam soils of pH 6 – 7.5 are best.
- Put the seeds 2cm to 3cm into the ground. The plant can have up to a planting rate of 800 000 per acre (roughly 100 plants per square meter). Keep the seeds closer together if growing hemp for fibers since this will make them grow up rather than branch out and spread the seeds further apart if one wants to harvest the seeds.
Caring for the crops
- The plant grows fairly quickly reaching maturity in between 3 to 6 months.
- Water the hemp 30cm to 38cm throughout the growing season. Watering is especially important within the first 6 weeks of growth while the plant is still young and after that, hemp is drought-resistant can survive without water for a few days. Long tap roots allow the plant to reach water and bind the soil in places that other plants cannot. It can therefore be used to reclaim land in regions prone to drought and flooding.
- Hemp, being leguminous plant, fixes nitrogen into the soil and thus requires little fertilizer and no pesticides. However, nitrogen rich fertilizer has to be applied once the seeds have germinated on a warm, dry day so that it does not stick to the plants. Water the hemp immediately after fertilizer application to allow absorption into the soil.
- Pre-emergent herbicides are recommended for protection against weeds while the plants are growing. However, the plant grows very fast such that it chokes out weeds and has a strong resistance to pests.
Harvesting hemp fibers
- Collect the stalks with a sickle when the seeds start to develop
- Pile and leave the stalks in the filed for 5 weeks to allow for a process of rotting known as retting.
- Separate and dry out the stalks in a cool, dry area until they have a moisture level of 15% (below which the fiber can then be harvested) as determined by a moisture meter.
- Use a decorator (a machine with 2 rollers that break off the exterior pieces of the hemp stalk) to separate the fibers
Collecting hemp seeds
- Harvest the seeds with a sickle after 16 weeks when the leaves have fallen off and the seeds pods near the flowers feel dry and hard.
- Hold the top of the stalk and cut just below the lowest seed pod with a sickle. Leave any fallen leaves in the soil to use as compost for the next year.
- Thresh the seeds and winnow to remove any residue. Keep the seeds in an area between 0 degrees Celsius to 4 degrees Celsius so that they do not germinate. Seeds can be kept in a sack if moisture level is below 12%
- Market prices for hemp grown for CBD range between US$30 to US$75 per kg of biomass. Each plant will yield roughly 500 grams that can be used to source CBD and with between 3000 to 4000 plants per hectare, hemp farmers could be looking to generate upwards of US$60 000 per hectare of hemp. Potential returns for hemp fiber go up to US$1 890 per hectare and up to US$2000 per hectare for hemp seed.
Conclusively, hemp looks more and more like a plant for the future as it certainly speaks to both food security and agribusiness, thanks to its organic nature and versatility. A single stand can be the means through which families can get to feed, clothe and house themselves at the same time earning some dollars. The global cannabis industry is expected to be a US$46 billion business worldwide in three years up from US$16 billion this year. It is only up to the Zimbabwean government, the private sector and international partners to work closely together to build a successful new sector for Zimbabwe’s growing agricultural industry.