Discover The Secrets To Growing Hemp
Hemp has had a strong association with cannabis used as a recreational drug (in this respect often termed “marijuana“), and although the two stem from the same Cannabis sativa plant, hemp and cannabis for recreational use are completely different products.
Cannabis sativa is one of the oldest cultivated plants on the planet. For a long time, its excellent fibers have been utilized in the making of ropes, sails, clothing as well as other products. As part of an international effort to limit the effect of using Cannabis sativa recreationally as a drug, due to its contents of the psychoactive substance Tetrahydrocannabinol, known better as THC, hemp has been strongly associated with recreational use of cannabis and more than often banned along. It was banned internationally in 1961 under the United Nations’ Single Convention on Narcotic Drugs. The market for hemp products shrank considerably due to this association.
While hemp and its cultivation remain banned in the United States, other countries, including Canada in North America, gradually introduced regulations that permit growing hemp for industrial uses, provided it does not contain more than a given maxium amount of THC per gram. In Canada specifically, the Industrial Hemp Regulations of 1996 allow for controled production, sale, movement, processing, as well as importing and exporting of industrial hemp and its production if they conform to conditions imposed by those regulations. In Canada’s case, products made from hemp may not contain more than 10 micrograms of THC per gram. In addition, licenses to grow hemp industrially are issued for each calendar year and must be renewed every year.
General Information On Producing Hemp Industrially
Industrial hemp is made almost exclusively from different plants of Cannabis sativa containing usually less than 0.3% THC. The plant is an annual broadleaf, capable of growing very rapidly under ideal growing conditions. The flowers and seed set are indeterminate, meaning there are both ripe and immature seeds on the same plants at the time of grain harvest.
When hemp is grown as a fiber crop, it may grow to a height of 6-12 feet . The stem has an outer bark containing the long and tough bast fibers, which are similar in length to soft wood fibers. These are the strong and quality fibers which are typically used in making of ropes and other products for which hemp is renowned. The core contains short fibers, more similar to hard wood fibers, and these are better used in other contexts, such as horse bedding.
When used for grain production, plants may branch and reach a height of only 6-9 feet.
There are several varieties to industrial hemp commonly used. The first is the so-called dioecious, which has male and female flower parts on separate plants, and monoecious, which has male and female flower parts on the same plant. There is also a third type, known as Female Predominant, which is typically a dioecious type containing 80 to 90% female plants. This type is very common in France.
The varieties of hemp used for industrial production have a distinct set of characteristics. They have have small or large seeds, high or low oil content, and so own. Varieties may contain from 15 to 25% of bast fibers. When approaching the task of choosing the right variety for growing hemp, the end production should be in mind for the specific market needs.
Soil Conditions and Planting
Hemp typically requires well drained soil, with an acidity (pH) level of above 6.0. In general, the soil should not contain a lot of clay, as this will lower the yield of fiber or grain. Young plants in particular are quite sensitive to wet soils or flooding during the first three weeks, so care should be taken during this time not to use too much water.
Generally, using sandy soils is complicated, as they provide not enough natural fertility and support for the plant, which requires using extra nutrients and water in order to obtain maximum yield. This, however, may result in higher costs, which usually renders using sandy soils uneconomical for producing hemp.
Industrial hemp needs a very good soil contact to get the best germination possible. To this end, the seedbed must firm and relatively fine. As soon as the soil is dry enough to avoid compaction, planting can begin. A shallow, firm seedbed will allow the seed to placed uniformly.
Normally, industrial hemp can sown using a standard grain drill at a depth of 2-3 cm. The best oil temperature at that depth to achieve a swifty germination is 8-10oC, but hemp will germinate at lower temperatures, too. In terms of distribution, industrial hemp is typically sown in 15-18 cm (6-7-in.) rows, with a best final stand of around 200-250 plants/m2. Seeding is recommended as soon as soil conditions are met, and there should be no less than 250 seeds per a square meter. In case the seeds are large and germination may be low, the rate could be higher. However, in general, seed density is specific to each variety, and this data should be made publicly clear with each delivery of a variety; in other cases, seed density information may be queried directly from the seed supplier.
Fertility and Weed Control
Hemp is known to require around the same amount of fertility as a good wheat crop. Recommended are around 100kg/ha of nitrogen, although this depends on the fertility of the soil and past values using the same variety and soil. Other nutrients such as phosphorus and potash may be recommended too as nutrients, with different quantities. For reused soil, almost a half of the plants’ biomass returns to the soil in the form of leaves and roots, which contain more than a half of the nutrients supplied to the crop. For the next use, calculate this as part of the equation, as those nutrients will be used by the subsequent crop.
Hemp’s fast growth, particularly in a well-drained, fertile soil under optimum temperature and moisture assures that it germinates quickly and reaches a considerable height (30 cm, 11 in.) in around a month from planting. At around this time, the hemp will give an almost 90% ground shade, which will suppress the growth of weed by excluding sunlight from it. Rapidly growing hemp will suppress nearly all weed growth. In particular, perennial grasses may be weakened or destroyed completely if the hemp is grown a second year on the same soil, however this may make it more vulnerable to crop diseases.
When producing for grain, weed suppression may be less effective, as the lower growth of the plants allows more light in.
Harvesting #1: Retting / Turning
Retting describes a process of separating the bast fibers from other plant parts. It is done directly in the field, utilizing aspects such as rain and sun to its favor. It is also possible to do it under controlled conditions, using water and chemicals. The method in use depends on the end use of the fiber.
Field retting involves nightly dews and good daytime drying. Adequate dew conditions depend on the climate, but in the Northern Hemisphere, this process should be done no earlier than the end of July. Of course, this largely depends on the planting date and the variety of hemp chosen.
The retting process generally takes three weeks to a month. The windrows are turned strongly with a rake or a similar apparatus to knock the leaves off the stems. The retting process must be completed before baling, such that the fibers reached the needed color, without rotting in storage.
Harvesting #2: Baling and Storing
In an industrial manufacturing environment, a large, square bale may fit better into the processing setup, although round bales are the best in letting bales dry more quickly in storage, whereas square bales are packed more tightly, allowing for less air passage.
At any rate, the resulting bales should be stored indoors in dry conditions in order to stop the retting process and prevent rot. Stalk moisture should be ideally less than 15% while baling, and drop further to around 10% later.
As far as other harvesting methods are concerned, such as combining, these form a challenge while working with hemp. This is due to the fact that hemp straw contains very tough fibers that tend to wind around moving parts. Other aspects of the plants may cause a lot of friction using the equipment, which eventually causes machinery wear, resulting in higher costs. Generally, shorter varieties are easier to combine.
The costs of producing hemp industrially depend on many different variables, such as the size of the acres, the yield, as well as the cost and age of the equipment used, not to forget the costs of the seed and the quality of the variety of hemp used. Land reuse, particularly due to the possibility of diseases, pests following repeated growth of the same plant on the same soil, may also count in financially.
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