One of the more expensive local fruits we have is the Durian Belanda. Both the fruit and the leaves have good nutritional and therapeutic values. I have been growing the trees for about 7 years now and to date and currently we have 8 trees of various ages ranging from 3 years to 5 years. Many have asked me many different questions hence this article covers my experience and each growers experience can be different.
Although it is a tree that can grow to over 8m in height, the growth can be controlled and it needs a space of a circumference of 2 m. Giving the right conditions and care, it can produce many fruits. Let’s start with the basics: the soil. At the farm, we have different sections with different soil types ranging from high clay content to rocky and high sand content. We have experimented planting them in various areas and find that it does best is soil that contains a significant amount of sand (around 30%) and does worst in high clay content soil. It needs soil with good drainage with good content of organic matter to a depth of at least 1 m. If you are living in a development area that was developed in the last 10 years, and you find that your tree keeps dying, check the soil. Many of these development had used construction and other wastes as landfill.
This tree is well suited to our tropical climate with frequent rain with some dry periods. In young trees, it will need to be watered. Once a tree has established itself, it will no linger require manual watering. The roots tend to spread out relatively neat the surface of the tree and the root doesn’t grow as deep as other trees of similar height and girth. It does not like for its roots to be disturb hence for this reason, we refrain from planting any plants around the base and keep the grass and weeds controlled by cutting the down to surface level. This serves a dual purpose: adding organic matter which as it decomposes adds nutrients to the soil and to keep the soil covered to help retain moisture.
Our farm is totally organic so we do not use any chemical pesticide, herbicide or fertilisers. To this end, the environment of the farm is such that we plant many different types of plants and trees that encourages many varieties of insects, some of which are predators to insects that attack the leaves and fruits. This helps to keep the trees relatively free of insect attacks. Having a healthy tree also helps it fights these attacks and diseases.
To support the growth of the tree, we address the soil health as well as the plant health. In order to ensure that we have the necessary
nutrients to support flowering and fruiting, we use goat and chicken manure fertilisers. We also use diluted fish amino acids mixed with EM-1 on a quarterly basis. The tree can flower year-long so keeping it well-fed is essential. The bell-shaped buds are green in color with the point facing downwards. There can appear singularly or in multiples.
As the bud develops, you will see it turn to a pale yellow flower with petals.
An interesting aspect of the soursop flower is that it blooms at night hence pollination occurs at night. Once the outer petals are open (as in the picture), it will bloom that night. At the farm, our environment encourages night insects as well as there is often night breezes which contribute to a good pollination rate. We do not hand pollinate.The presence of wind and night insects is important to increase the success of pollination. The degree of success of the pollination will also affect the fruit size and shape.
Once the petals have fallen, you will see a stub-like with :needles” left. Some have mistaken this as the dried-up flower and removed it. At this stage, it is still unclear if pollination is successful so it is best to leave it. Over the next few days or a week, you will see the beginnings of the fruit if pollination is successful, It doesn’t look like the fruit yet but a brown mass of pins.
From this stage, it will take several weeks before you begin to see the fruit in a shape more familiar to the mature soursop. You can see that the fruit will h
ave a nice shape and size when mature from the shape the fruit “bud” is as well as the number of “needles” present. Even when it is flowering and fruiting, we continue to fertilise the ree in accordance with our schedule. We also on a bi-annual basis, spread a handful of coarse salt around the circumference of the tree about 1 m away from the base of the trunk. Apart from supplying additional minerals, it also serves as an “antibiotic” against harmful bacteria.
In general, the fruit is heart-shaped or oval. The fruit is ready to harvest when you see the needles are well-spaced apart and pointing horizontally an
d the skin of the fruit has smoothen out. The fruit will feel firm. At this stage, it will be sweet and sour with lots of juices. This is, to me, the perfect time to harvest if you would like to eat it in slices. I tend to just cut it into the slices, revealing the creamy-white flesh inside, without peeling and eat the flesh off, leaving the seeds and skin. Once it has reached this stage, it will go soft within days but the intensity of the sweetness will increase and the flesh will still remain creamy-white. However, it will then be suitable only for making blended drinks.
Often, when you buy at the market, the fruit will still be hard. Do check that the fruit have the “needles” almost horizontal and widely spaced apart with smooth skin in between. This will indicate that the fruit was mature enough when harvested. Often, people will wait for their store-bought fruit to soften and when they cut it, they find that the flesh inside is brow/black indicating the fruit has rotted. This could be due to the preservatives applied post-harvest to keep the fruit looking nice on the outside but it has started to rot on the inside, Hence, by the time you feel the fruit has softened, it has rotted all the way through.
PS>> This will be one of the fruit trees that I will detail out from planting to harvesting to what you can do with it more in my book. Not sure when I will complete it though 🙂