Hemp cultivars available
(Short introduction to the cultivar choice)
Hemp can have many uses but the main categories refer to the production of grain, stalk for fiber and shives and floral materials.
In addition to this classification based on product type, another common (and useful) classification is based on sex. The distinction is between dioecious varieties, i.e. varieties that have distinct male and female plants in the population, and monoecious varieties which are hermaphrodite (i.e. both sexes on the same plant).
It is remarkable that hemp life cycle is not determined in time, unless for rare cases. Flowering, and therefore the life cycle of hemp, depends mainly on the photoperiod.
Hemp is a short-day plant in fact it responds to the reduction of the hours of light, inducing flowering in late summer and early autumn. It’s important to remember that the number of hours between sunrise and sunset varies according to the time of year and latitude.
If you are growing hemp and you want to orientate yourself on the choice of variety and sowing time, these basic concepts must be clearly understood. For this reason, it is misleading to describe the varieties based on the days necessary for the completion of the life cycle.
Generally, we can distinguish the early flowering hemp from medium and late-flowering varieties.
Flowering can also be influenced by other environmental factors and each variety follows typical behaviours depending on the period of sowing and emergence, the latitude at which it is grown and the pedoclimatic conditions of the growing environment. Environmental stress can cause early flowering.
Therefore the information reported here is not univocal and shouldn’t be taken as scientific. Rather, it should be used and interpreted as general guidelines only.
The acquisition of empirical knowledge about the behaviour of a variety in the desired cultivation area cannot be avoided. Usually 3 to 5 agricultural season are needed to acquire enough knowledge, and for this reason, it is advisable for those who approach this crop for the first time to start with tests on several varieties, including at least 3 different cultivars.
We offer many cultivars that we are currently testing in our test fields, however, we report here only about those for which we have good field
Early and very early hemp varieties are designed for grain production. These types of hemp is characterized by a short cycle and a reduced growth habit, and it often has a good capacity to branch.
The reduced height makes mechanical harvesting easy with traditional machinery. Oil and protein content of the seeds represents an added value for these types of plants. In many countries the tolerance limits for THC in foods is very low. In Italy, this limit is set in the order of parts per million (ppm).
Hemp seeds do not physiologically accumulate THC in the embryo, however, during harvest, seeds are often contaminated by resins and consequently the derived products may show traces of cannabinoids.
The early and very early varieties generally allow growers to avoid exceeding the tolerance threshold of THC in food.
The medium-late flowering hemp varieties are designed to provide farmers with a double economic return. They are characterized by a good production of biomass (stem) that can be used to obtain fibers and shives, and additionally it yields a good seed production.
Grain yield is generally lower than the early varieties preferred for this purpose. A further consideration to be made when choosing these varieties is that later ripening can expose farmers to partial or total loss of seed harvest due to intense weather events.
Due to their greater vigour, it may be necessary to use mechanical harvesting systems specifically designed for hemp. Some of these varieties can additionally provide a third product to produce floral biomass; this biomass is suitable for the extraction of cannabinoids and secondary metabolites that are of particular interest to the pharmaceutical and cosmetic industry.
The three possible products described above, namely stem biomass, grain and floral biomass, are not perfectly complementary; yields and qualities depend on the stage of development of the plant.
It is therefore necessary to make a careful choice and decide what should be the elective product; Consequently the remnant products should be considered as by-products which anyhow retain a good economic value.
It is therefore necessary to pay close attention to the harvesting phase, which will be adapted to the main chosen product.
This type of hemp consists mostly of very vigorous and late-flowering varieties. Late dioecious hemp can reach a considerable height and they have a good fiber-biomass ratio.
Because of their vigour it is often necessary to have specific equipment for cutting the plants.
Nowadays they are also used with good results for the production of floral biomass from which cannabinoids and secondary metabolites of high interest for pharmaceutical and cosmetic industry can be obtained.
As a result of their vigour and late floweringthey generally accumulate more cannabinoids than other varieties.
Due to the low grain yield and the fact that they cannot complete the cycle profitably at all latitudes, the cost of certified seed for sowing is higher than other cultivar.