by Isabel Carter.
In recent years passion fruit has become a popular new fruit for many farmers around the world. They grow well and the fruit is tasty and refreshing. Unlike some fruit, passion fruit travel well to market. They can also be processed to make juice. There is increasing interest in exporting them to Europe where they are becoming a popular luxury fruit. Passion fruit will often grow well up trees but few people know much about the best methods of growing them to produce large quantities of fruit.
Varieties
The name comes from the flower which looks like Christ’s crown of thorns and the nails on the cross. The purple passion fruit grows well in higher altitudes. The yellow fruit is more commonly known as the granadilla. This has larger fruit and higher yields but a more acid taste. It grows best in hot, low-lying areas. Grafting purple passion fruit onto granadilla stock can prove very successful.
Plant breeders continue to produce new hybrids, though as yet these will not grow true to the parent plant, so can only be reproduced through grafting. The hybrid plants also sometimes need help with pollination of the flowers.
Diseases
Most diseases result from wound damage. Sometimes diseases can be controlled by cutting away the infected parts.
Build a reputation!
Passion fruit is a cheap and easy crop to grow. Building the trellis system is the major effort or cost, but if done well will last many years. If you are wanting to try passion fruit, it is worth asking around for advice on the very best variety and paying a lot of money to buy one or two excellent plants. Within a year or two you can have hundreds of young plants from the seeds of your first plants. Of course, you can also visit a market and select good fruit from which to plant seeds.
Why stop there? Continue to experiment with different varieties and try out grafting on a small scale. If you are successful, you may be able to sell grafted plants and build up a reputation. Consider forming a co-operative and trying to find a regular market to sell your crops – maybe to a local factory producing juice.
Raising seedlings
Seedlings can be grown in open beds but grow much better in small containers – usually plastic tubes, though tins, milk cartons and banana leaves can also make good containers. Containers should be 10cm in diameter and 20cm long. Fill them with good soil and plant several fresh seeds in each. Water regularly and cover with mulch until germination. Allow two or three seedlings to grow in each container. Plant out when 8–10 weeks old.
CUTTINGS from healthy shoots of particularly good plants can be made with a sharp blade. Cuttings should be about 15cm long with two or three leaf nodes. Cut off the lower leaf at the node. Plant cuttings firmly (about 5cm deep) into containers under shade and keep well watered for a month. Shading can then be removed.
GRAFTING uses strong seedlings of granadilla which are 20–30cm tall. Cut off the seedling, leaving a stump about 10cm high and make a 3cm cut into the top. Place into this a wedge-shaped shoot from a good quality, high-yielding variety. Cover the graft with plastic tape (cut up an old plastic bag) and keep the seedling under shade and well watered for one month. Remove shade and allow to grow for another one or two months before planting out.
Grafting a shoot onto granadilla stock.
Training young plants
Passion fruit grow best on trellises where they are well supported and planted 3m apart with 2m between the rows. At first the plants are trained up on stakes to produce what are called leaders. Allow two strong shoots to grow and remove all other shoots regularly.
While the plants are growing, build the trellis system (see below).
Once the leader shoots reach the wires they are allowed to grow along them. Secondary shoots will form and hang down, forming curtains of shoots. Try to keep these secondary shoots from becoming too tangled. Tight knots encourage diseases.
Tangling like this encourages disease.
Cut off shoots before they reach the ground to prevent diseases. Never throw shoots which have trailed along the ground back over the wire. Over the seasons, regularly cut out weaker or diseased secondary shoots – but never the leader shoots. Cut back shoots which have finished producing fruit.
Harvesting
The plants will begin to produce fruit 8–20 months after planting out. Fruit is produced throughout the year, but there are usually peak times for harvesting. Plants will produce for 3–6 years. Often the highest yielding plants will die back first. When ripe, the fruit will fall to the ground where they can be picked up. The ground should be kept clear of weeds, though some low ground cover can help to avoid damaging the fruit. The roots of passion fruit cover a very large area – up to 6m in diameter – and are often very near the surface of the soil. Even slight digging may cause damage. Planting low cover crops, such as cow peas, grass or lablab may be the best answer.
It is always best to let ripe fruit fall off. Picking the fruit means the juice is less sweet, the quality is reduced and wounds may be caused on the plant, leading to disease.
Building the trellis
It is common to see trellises which collapse due to termite damage after a year or two. Use good, strong timber which is either termite-resistant or treated with preservative.
Ideally, use stakes which are 20cm in diameter and 2.6–2.8m in length. Drive them 60cm into the ground and fasten fencing wire to them. There are various ways of anchoring the wire and rows or posts to keep them upright. Space the poles every 6m with two leader shoots between them.