Companion Planting in the Tropics – Vertical Stacking

Sweet potato and katuk (sweet leaf/sayur manis)

We have been playing around with companion planting at Project Canossian. Actually it’s more of stacking plants on top of one another rather than just adjacent. Lots of failures with some successes. It is something we have been experimenting with since our days at Project Green Valley. There are many good reasons why you would want to companion plant by vertical stacking:

  • Better use of sunshine: Here in Singapore 1 degree north of the equator, the sun is overhead throughout the year. As Bill Mollison says, a resource that isn’t properly utilized can become a pollution. Sunshine is photosynthesized by leaves and is turned into a yield (for us or other living things). However, when this strong sunshine falls on the soil many things happen. Soil water evaporates, soil organisms (e.g. earthworms) die from the heat, ambient temperature increases due to radiation. A single layer planting of small vegetables or herbs does not use the sunshine efficiently. Lets talk about planting lettuce as an example: for most of the growing duration, most of the sunshine will fall between the tiny seedlings onto the soil. Even when the lettuces are fully grown and touching one another, the leaves are not able to utilize all that good sunshine. One layer of leaf can only photosynthesize so much sunlight, after which the remaining passes through the leaf. Which is why the best use of sunshine here in our climate is still a forest. Almost all of the solar energy would be extracted as the sunshine passes through the many layers. Nothing much is left by the time it reaches the forest floor.
  • Better use of rainfall: Likewise, we are blessed (or, to poly-tunnel farmers, cursed) with heavy rains throughout the year. The kinetic energy of falling raindrops causes soil compaction and sheet erosion when not absorbed by foliage or mulch. Having more leaves to intercept and direct the water flow down the stems allows the soil to drink more gently. If there are not enough roots in the soil to absorb the rain it flows away, causing leaching of nutrients.
  • Shading out weeds: Nature doesn’t waste. Solar energy that falls on soil will be taken up by weeds. Mulching helps but we have seen weeds here that can penetrate mulch (cardboard or leaves) just to reach for sunlight.

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Becoming A Forest

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The forest beside the lawn

On a pleasant Sunday morning, I observed some interesting happenings along the edge of a forest at Lower Pierce Reservoir where I jog to or play football occasionally. There were some patches of upturned soil on the otherwise flat and trimmed lawn. It was somewhat thrilling because I felt like a detective at a crime scene, gathering clues to figure out what happened. Even better, I also felt like a hunter tracking a prey by reading signs left behind to foretell what might happen in the future. Here’s the story of what I think happened…

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The crime scene: upturned soil and an unknown fruit

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Digging a Banana Circle

Digging Banana CircleOne thing I really enjoy at a permaculture garden is that you can litter without feeling guilty. Growing up in spick-and-span Singapore we have been taught since young to put litter only in the rubbish bin. Any piece of trash left on the concrete floor is an eyesore and has to be cleaned up by someone else. This is why it felt so liberating when I could throw my organic waste anywhere in the farm. In fact, my act of littering will be adding to the fertility of the soil and if I was lucky it might even be seeding a tree!

The banana circle is a simple yet effective design for permaculture in the tropics. It is basically a circular trench with bananas planted at the rim of the trench. All kinds of organic waste can be thrown into the circle, including dead leaves, garden prunings, kitchen waste, hay, rice husks, even short logs. Anything that will rot can be thrown in. As the organic matter breaks down, the hungry banana trees will readily suck up the nutrients and turn the waste into yummy bananas. The depression into the ground helps to retain moisture that the bananas love and also speed up decomposition. Continue reading

Building Houses in the Air

Malay house under coconut treesI’ve been reading a lot about the traditional Malay house. Contrary to its simple and humble appearance, there is actually a lot of thought that goes into the design. Thoughts that factor in climate, available resources, and lifestyle. This house is evidence of human ingenuity before we started relying on air-conditioners and big diesel-guzzling lorries.

Books have been written about the simple Malay house and there is too much to be said. In this post I will focus only on how the house has been adapted to the humid tropical climate. Continue reading