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What would be a suitable media mix to ensure adequate capillarity and soil quality for seedling and cuttings?

Since the WB will be in a aquaponics system it will be of the Earthan type, if there is no inconvenient..

Any help much appreciated.

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Here is a Youtube link to Michael McGroarty's video about rooting cuttings.

Michael has a little booklet I received, A Simple Way to Root Cuttings of Your Favorite Plants.  I think he gives it away free, You have to pay postage.

Thank you Paul. Very interesting site.

My concern is more of the structure of the mix that of it's ingredients.

Imagine a 2 mm broccoli seed 2 mm below the surface of the WB. The bottom of the gravel (Earthan) will be about 2 feet right down. I want to be sure that humidity will reach my seed, crossing upward 12" of gravel and 12" of this media with excellent capillarity characteristics.

I use what I call, grow boxes, which are wicking boxes.  I use a plastic cover with holes cut for the plants.  That way when the sun shines on the plastic, it causes the water to evaporate up through the media, condense on the plastic and settle down into the media.  This allows a reduced need to add water.
Here is a picture of the boxes I use in my aquaponic system.

Here is a picture of the box construction.

Thank you Paul, very interesting the evaporation job. Here is a picture of my planned "grow box". That's the one on the right side, it's 28 by 7 feet. Height is just good for 1 foot gravel and 1 foot media mix. Temperature is 86 All year long, I should be able to get some evaporation.

What do you think of that.? By the way those infrastructures where a bananas packing plant which I reconvert in Aquaculture/Aquaponics-

Hear is a link to the Earthan Group in Australia. 
Here is a short article about the man behind the group.


Paul Van Der Werf has a long and diverse career within the agriculture and aquaculture industries. It all started at the age of 17 when he commercially farmed bananas and pawpaws, with seasonal small crops on 40 acres and selling to retail and wholesale markets while studying engineering.

During that time, his passion for ecology and environment conservation started with extensive work over 10 years with The Australian Crayfish Project where he has co-published papers on the conservation status of some the most endangered species in Australia.

His love for aquatic habitats saw him take his engineering and drafting skills, along with his deep understanding of aquatic ecology into the world of aquaculture and has provided key consultation to numerous commercial and research aquaculture projects.

Through that period, he became and still is the President of the New South Wales Aquaculture Association which is the peek industry body representing 160 farmers.

Paul has been the key figure to the success of many projects throughout the world, and has provided advice to many aquaculture professionals and keen enthusiasts alike.

Recently, Paul completed the construction a 4400m2 integrated aquaculture pilot facility in the harsh desert of United Arab Emirates using one of his unique state of the art designs.

So dedicated to the success of such a project of key importance to the ever expanding industry of integrated aquaculture, he spent 12 months onsite helping the owners start the business up and train the staff. This facility is the first and the largest of its kind in the world to date and will prove to be a guiding light to future commercial expansions.

With his spare time Paul, generously delivers some of the highest quality information Aquaculture and Integrated aquatic farming through training facilities and his social and professional network.  Still he maintains his role as the Research Coordinator and major financial sponsor of The Australian Crayfish Project in collaboration with his good friend, Robert McCormack.

I have found that coconut coir (chopped coconut husks) to be very useful as a wicking medium. The medium is much like peat moss in action, and offers nothing to the the growing plants in terms of nutrients. That would likely be in the water used to irrigate the plants. As long as there is a separation between the gravel and the coir, I have not found any issues with water transport. I have used landscape fabric to make the wicking bed separate from the gravel. When using the coir, you would want finely chopped coir, as opposed to rough or medium.

The coir allows for easy root growth, including root crops like beets or carrots and does not pack down the way some earth does. There is a practical limit to what distance the coir can transport water. I would guess that 10 inches might be a practical limit, so planting deeper or bring water levels up to that level, may prove useful until the roots go deeper into the coir.

Coir comes in compressed dried blocks of various sizes. I've worked most with the 1 and 2 kilo blocks. When rehydrating them, allow 12 or more hours for the coir to expand and rehydrate fully. Some people will add compost to the coir basic, but I have found that is not necessary for wicking. Others have added perlite to the coir, and for columns of strawberries that worked for me as it was dripping from above, and I wanted a faster transit of water through the whole column. I have not tried to wick up with a perlite / coir mixture.

I do have some red worms in my coir, not planted there, but migrating from the gravel, I suspect, where I do have red wrigglers.

I hope this helps with your needs.

Hi Loyd,
I see that You are a close neighbor here in Western Washington.  We need to get together and trade lies sometime.

I have been studying the cost differences here in Western Washington between sawdust and coir.  The cost of sawdust being very significantly less than coir.  Here where I live, we have several sawmills where sawdust is available practically for the taking.

I went on line to find if any studies had been done comparing the two grow mediums.  Here is a link to a study I found that was very interesting.$department/deptdocs.nsf/all/opp4542
This next week I will be picking up my first Yard of sawdust to try in my wicking boxes.

Are you going to be recycling water back to the fish from your wicking bed? If yes, check the effect of sawdust on the fish; usually a problem.

If you are only using water from the fish and NOT returning water to the fish, I expect that things will be OK.

The reason I use coir is that it does not affect the fish and my water does recirculate. The coir is at base inert relative to the fish.

Hi Paul & Lloyd, what I did is on the pic. Finally the mix is 1/2 very fine sand and 1/2 very coarse wild humus. That's just what I had at hand. Since the transport was very efficient I got scared of rotting seeds. So I put a "retardant" as 2 " very fine humus very suitable for germination. The water reached the top merely in 12 hours. That's suit my purpose.

I didn't put saw durst because I didn't go and get it.....And yes the water is recirculating....I was sweating the whole following afternoon.

About the coir I'll put it in the second half. The first seedling is esoteric as there is moringa, chia, lavender, cocoa and 12 others. Thank you for your efficient advices.


Before you do the second batch, keep an eye on your fish. While I doubt there is anything nasty in your "wild humus," but it is always a possibility. Any insecticides or herbicides or fertilizers in the wrong concentrations can harm the fish. If every thing is nominal in two weeks, probably not a problem.

you are very right about the risk. As a matter of fact I'm more confident in my wild stuff than the bagged one.

This AP is one the breeders. See them, some are above 4 lbs, and some off springs in their fast food.

I shall figure out some testing procedure.



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