Handbook of Vanilla Science and Technology

The most preferred method is the use of wooden posts 3 m in height to which the vine is tied up for the ease of access for pollination and harvesting (Figure 5.2). The vine is then allowed to grow straight upwards, emulating what it would do growing on a tree in the wild. When the vine has reached the top of the post, the upper half is carefully peeled off and draped over the round cross support set at a height of 1.2 to 1.5 m maximum. The vine is then looped to the mulch bed and allowed to climb to the top again so that the process is repeated. Some success was achieved with the use of an artificial post made of a drainage pipe covered with a non-woven geo-textile (Figure 5.3). These 3-m long pipes are attached to a tensioned steel cable in a way that their base can be buried in the raised mulch bed.

Fig. 5.2 Diagram of wooden post method for growing vanilla.

Fig. 5.3 Vanilla plant growing on a post made of drainage pipe.

In Darwin, coco peat filled wire mesh tubes have also been tested as an alternative support to timber posts (Figure 5.4). While these proved very suitable for vine growth and support, they made training more difficult. Removing the portion of the vine to be looped without damaging roots proved difficult and increased the likelihood of damage to the vine if extra care was not taken in peeling it off the upper portion of the tube. Also, the mesh tubes (posts) did not have cross supports over which the vine could be draped, requiring tie off or spike to support the loop.

Fig. 5.4 Vanilla plant growing on a coco peat filled wire mesh tube.

The benefits of using the wooden or artificial post systems in a shade house are:

• an increased yield per hectare through increased plant density;

• improved control over growing conditions, including the efficient application of irrigation and fertilization regimes; and

• greater efficiency in the operation of the plantation as the frequency of which the plants must be trained is reduced by the taller posts.

Another approach that may hold promise for implementation on small (hobby) mango farms of 5 to 5 acres is using established mango trees as supports. This has the advantage of diversifying and improving the sustainability of these small farms, which are at risk of being pushed out by larger corporate operations. However, the use of mango trees may present a two-edged sword, as mango trees in the Darwin region are at risk of the soil-borne fungus Fusarium, which has caused Mango Malformation Disease. This may be a serious threat to vanilla in the Top End, but good management and plantation design should eliminate this risk.

5.11 LIGHT/SHADE

Vanilla, like many orchids, is a shade loving plant. It prefers 50 to 60% shade and good to strong indirect light. While shade is necessary it should not be too overbearing, and an eastern exposure is preferable.

5.12 SPACING

Grown in its traditional woodland setting, the spacing of the vines is dictated by the spacing suitable for the support and shade trees. Typical spacing for the supporting trees is usually 2.5 to 3 m between trees and between rows. If vanilla cultivation is to be developed in an established mango plantation, spacing will be dictated by the existing trees. In a mature plantation this will be around 8 × 8 to 10 m. However, in the shade house environment, using timber posts for support, the plant spacing can be reduced. The inter plant spacing can be reduced to as little as 1 m, but 1.5 m is preferred, to allow the easy movement of workers among the crop. It is suggested that the row spacing be adequate to allow the mechanization of some plantation functions where possible; a minimum of 1.8 m, and preferably 2 m to accommodate a small vineyard style tractor or quad bike to assist in manual activities. This offers the best balance between increased yields and reducing the spacing to the point where it is a potential problem should a disease, mould, or pest occur in the plantation.

5.13 TRAINING

Left to grow on their own, the vines will climb straight up the support to which they are attached, such as a tree. However to make the plant more accessible for workers to pollinate and harvest the beans, it should be trained to a height of not more than 1,500 mm. As the vine can grow up to 15 m in length, keeping it compact and accessible is achieved by looping the vine, which also aids in encouraging flowering. This is done by allowing the vine to grow up the support to twice the height of the desired level. Then carefully detaching the upper half of the vine and draping it over the cross support to the ground, with two nodes in contact with the mulch/humus and allowing it again to grow up the support. In doing this, the vine should be spaced around the support evenly.

5.14 FLOWERING, FRUIT SET, GROWTH, AND MATURATION

5.14.1 Flowering