The Great Container Mix Experiment - Part 3 Coconut Husk Chip Mix

In the mail today, I had my coconut husk chips arrive from an online store. The husk chips come in a compressed block which expands as you pull it apart and add water.

The brand that I have found available in Australia is designed for use in orchid growing and has been pre-washed a number of times according to the product description. It is important to have washed coconut husks, as they may otherwise contain high level of salts.

Coconut Husk Chips

I have no set formula for this following mix, and in the past have made it up using whatever ingredients I had laying around and whatever needed to be used up at the time. I really like the texture and feel of the coconut husk chips, as the mixes always come out light and fluffy, and you can just imagine the pockets of air that sit throughout. Coconut husk chips also hold water extremely well.

In general though my mix contains mostly coconut husk chips, but also pine bark, perlite and compost. I always add a little composted bagged manure as well.

I have a number of plants potted in this mix, some of which have gone dormant throughout winter, and some that have put on slight growth. Weed seeds constantly germinate however, and from pulling these out, it becomes easy to see how the roots of plants seek out the husk chips, and their roots grow into the husks itself, a property that pine bark can't match.

Plant Roots Grow Right Through the Coconut Husks!

My logic might not be quite correct here, but I think that if plant roots can not only take up the vacant space within a container, but also through the media itself, surely this will allow more overall root growth?! At the end of this experiment I will upend all the plants and compare the root development of each.

Today I also received with my order a bag of diatomaceous earth, graded to a 5-8mm size. This product looks similar to perlite, or a white rock, and is in a similar size. It has quite a number of properties that make it suitable for container culture, such as its ability to exchange nutrients, buffer soils, hold water within its porous body and will not break down over time, so it suits itself towards long lasting potting mixes. Both coconut husk chips and pine bark also are long lived, and a media made from these substances can often last a number of years.

I decided to add equal amount of perlite and diatomaceous earth to this mix, something I have not tried before.

Making the Mix

As mentioned above, coconut husk chips come in a compressed block. It is quite light, and I prefer to break it up with my hands before soaking it. I used a whole block with this mix, which makes up about 60-70L pure coconut husk chips.

Compressed Coconut Husk Chips

With the Help of a Screwdriver it Took Only a Few Minutes to Break This Up

The coconut husk chips expand quite a bit more once wet, so I split it into two container to mix up in two batches.

Once Wet the Coconut Husk Chips Almost Filled the Wheelbarrow

Once I split the mix I added two pots worth of large composted pine bark pieces. These pine chips were rated at 15mm, and are double the size of most of the pieces used in the 5-1-1 mix.

Two 8L Pots Full of Chunky Composted Pine Bark 

After the pine bark I added one pots worth of perlite, and one pots worth of diatomaceous earth.

One 8L Pot Full of Perlite

One 8L Pot Full of Diatomaceous Earth

Diatomaceous Earth Looks Similar to Perlite, it is Made Up of The Fossilised Remains of Diatoms

Next I mixed everything up and then added one full pot of bagged compost, and half a pot full of bagged composted chicken manure. I also added one handful of dolomitic lime, a small handful of Osmocote and two handfuls of organic Dynamic Lifter, for comparison with the other mixes.

One 8L Pot Full of Compost

One Half 8L Pot of Composted Chicken Manure

This is the final ingredient for this mix, so I gave it a really good mix with the shovel, and added a bit more water to any dry bit of husk I saw. 

The Final Mix Looks Like This

Close-Up of the Final Mix- Very Porous and Light

I added the mix to my pots and lined them up ready for the experiment to begin!

In these pots, the closest three will all be grape tomatoes, the next closest fatalii chillis, the third closest basil or silverbeet (or whatever catches my fancy!), and finally banana chillis.

Previously I said I was going to germinate each seed in its respective pots, but due to the fact winter is not over yet, I have thought better and will germinate all seeds on a heat-mat in my greenhouse until they are of a size to transplant. This will mean that the pots will stay vacant for several weeks. In the meantime I will keep them damp, so that they don't become hydrophobic.

All My Pots Lined Up Ready to Begin!