What are Cempedak?
Cempedak (Artocarpus integer) is a relative of the jackfruit from south east Asia. The fruit are smaller, less acidic and less fibrous than that of the jackfruit. They are also much easier to process and eat out of hand. Seedling trees usually begin producing by their sixth year in the tropics. Cempedak are one of my favourite trees and one that I have always wanted to grow. Unfortunately they are a very tropical tree and Boobook Farm is in the subtropics. I am going to try anyway.
The Subtropical Cempedak ExperimentSo the cempedak experiment is an attempt to grow the tree in subtropical Brisbane, Australia. Up until this point I have found no record of cempedak grown in the subtropics. I have heard from growers though that it can survive temperatures down to 1°C (33.8°F). At Boobook Farm the coldest we get is about 3°C (37.4°F) so the experiment should technically be possible. The concern of course is that in the subtropics there is actually a winter and while cempedak may be fine with a brief cold snap in warmer climates, sustained low temperatures may kill the tree.
Germinating Cempedak Seeds
I received my seeds in late winter from an acquaintance who had just returned from a trip to Thailand. They had brought the seeds of three varieties back With them and by the time I received the seeds they were already about two weeks old. Now cempedak seeds only last a matter of weeks in storage and so I needed to germinated the seeds as quickly as possible. This was a problem as although large trees may be able to handle a subtropical winter (maybe), germinating seeds at these temperatures is a different story.
I planted the seeds just under the surface in plastic pots with a free draining mix. The potted seeds were then placed in my garage inside a large plastic tub to which I affixed a heat lamp. I used a foam lid to cover half the top, keeping heat and humidity in the tub. I also let water pool in the bottom of the tub to further up the humidity. To my surprise the seeds germinated within days. Currently I have eight little cempedak seedlings sitting in my garage awaiting my next move. Now to decide what that next move actually is! Do I create a protected greenhouse and grow them out for a few years before letting them face a winter? Or do I plant them straight in the ground and let the strong survive? Let me know your thoughts.
Make sure to read on to part 2 of the cempedak subtropics experiment.