The vanilla is the fruit of some orchids of Mesoamerican origin of which the best-known species is Vanilla planifolia. It is a tropical plant that forms lianas and requires special cultivation and preparation conditions (60% shading, temperature between 21 ° C and 32 ° C). One of the specificities of vanilla cultivation is its mode of fertilization. The male and female reproductive organs are separated by a membrane making it impossible to self-fertilize. Non-spraying pollen also prevents cross-fertilization by transport through wind (Carbon 1992). Fertilization is therefore possible only by the intervention of insects (only in its original area) or of man.
Flowering begins the 3rd year after planting. The brief life of the flowers (a few hours early in the day) requires fertilization early in the morning and in dry weather because the rain slows the formation of the fruit. Vanilla needs about 2000-2500 mm per year and water stress of 45 to 60 days from the third year for flower initiation. These specific growing conditions make vanilla one of the most expensive spices in the world whose production needs to be monitored for good yields.
Growing vanilla in a greenhouse
The objective of vanilla cultivation in a greenhouse is to reproduce the conditions present under the rainforest canapy. In order to do this, you have to control the climate parameters (temperature, humidity…) using equipment such as fogging, shading screens…
In addition, the greenhouse helps to protect the vanilla against climatic hazards such as excess water that would cause the onset of diseases. Moreover, the greenhouse will also facilitates the intervention of the man year-round ensuring a regular follow-up of the growth of the orchid.
In the photo above, we can see Vanilla tahitensis : a hybrid variety of vanilla found in Tahiti, French Polynesia. It is known to be one of the most fragrant vanillas in the world. Indeed, the Tahitian vanilla differs from other vanillas by its strong notes of anise, vanilla and caramel.
Moreover, the pods of Vanilla tahitensis do not open at maturity like the Vanilla planifolia of Madagascar. Indeed, they remain fleshy and can be picked at maturity. The mature “black” vanilla pods are harvested directly from the plant (photos below).
Advantages of growing in a plastic greenhouse vs a net house
Nowadays, a lot of vanilla farmers are using light steel structure covered with a single sheet of net to grow the vanilla. However, having a plastic greenhouse controlled by a climate computer has several advantages to grow vanilla:
_ Better control of the climate inside the greenhouse (growing area) to monitor and manage the relative humidity (RH %), the temperature and the light transmission more accurately ;
_ An efficient ventilation to drain out the humidity when it is needed also to recycle the air (CO2/O2 ratio) ;
_ Higher density of production inside the greenhouse (20 lianas / m²) : thanks to the air circulation and the ergonomics of the greenhouse ;
_ An optimal growth (up to 25 cm per week) and a constant monthly flowering ;
_ Integrated pest management and a better protection of the growing area against the pests and diseases ;
*A dedicated article will introduce the “vanilla kit solution” using a modern plastic greenhouse fully equipped with a proper ferti-irrigation system to grow the precious beans.
Do not hesitate to contact me by email if you have any question(s) about this technology for your future project : [email protected]
Photo credits: personnal pictures from Corenthin Chassouant