Contemplating Wicking Beds

[Richard Mong]

Hello All,

I realize now that though I just posted a comment, it doesn't do justice to all the hard work I put into Google Sketchup drawings. So, here I go again. I've included the bit about my system, in general, as I'll do anything at this point to get feedback. I mean, I'm building it right now, and if something looks screwed up, I'd love to know.

System Overview

At last, a system that I'm satisfied with-- and just in time, too.

The aquaponic component is pretty simple, and I’ve gone on at length about how it works before, but here is a reminder. The fish in the tank are fed. Initially, I’ll use commercial, high-quality fish feed, but eventually I’ll transition this to a combination of worms and other sources produced on site. The water is recirculated. In fact, the fish tank water should be cycled about 18 times a day. The water from the fish tank, along with the fish poo, uneaten feed, and other waste products such as ammonia pass first through the the larger blue barrels. These are known as swirl filters. The heavier solids swirl down to the bottom of the barrels where they are removed, probably a few times a day. What’s left is water with the finer solids still suspended. This stuff passes through the first of the smaller barrels. After a lot of thought, I’ve decided to use a mixture of coir (coconut husk fiber) and rice husks in a 70:30 ratio. This mixture will be wrapped in mosquito netting like a giant teabag. Two things happen here: first, the suspended solids are trapped in coir fibers, and second, the immense surface area is home to the bacteria that convert the otherwise noxious stuff to plant food. The bacteria have other homes, too; in fact, every surface, including the underside of the Styrofoam rafts. It’s this suspended solids media that I’m particularly satisfied with (if it works). First of all, the rice husks are free, and if I can’t get coir for free, it won’t be expensive. But the great thing is that it’s all organic. Coir is rapidly replacing peat moss as the main ingredient in soiless potting mixtures. So, instead of using orchard netting as the filter media, which would have to be rinsed periodically, I can just replace it with more coir and rice husks. And what do I do with the gooey stuff? It goes to the wicking beds, of course. Let me just say that wicking beds are tremendously sexy. More about them later. The final barrels are just a “degassing” zone. Significant aeration removes methane and other nasty stuff from the water. They will also serve as a vehicle for tweaking the PH of the system water when necessary by adding hydrated lime, etc.

Aquaponic Component

While wicking worm and potato beds are a new component in the overall system, the aquaponic component has gone through some nice evolution. The greenhouse length is now more than 2 meters shorter yet maintains roughly the same level of production. There are 3 longer hydroponic troughs instead of the 4 shorter ones, allowing me to eliminate one set of filtering/degassing contraptions. The system details are as follows:

• Fish tank water volume: 8,000 liters
• Annual fish production: 1 to 1.25 tons
• Hydroponic trough water volume: 16,200 liters
• Annual lettuce production @ 3 weeks on rafts: 15,600 heads
• Freshwater prawn production in the hydroponic troughs: not sure

 Wicking Beds

Lateral drift is my best friend. The world is, luckily, full of lots of clever people. I’m not going to bore you with the science behind wicking beds; if you want more information, try reading this. From the same source, “The wicking bed system is a way of growing plants in which water wicks up from an underground water reservoir. The major advantage is a significant increase in production while water use has been shown to be reduced by up to 50% of conventional practice.”

Step 1: Wrong Way Wicking Bed

Here is how I’m intending to make my wicking beds for potato production. I will discuss potatoes at length in a later article. First, dig the reservoir pit. This is about 20cm deep. The reservoir should not be deeper than the capacity for water to wick, which depends on the wicking media, but coir can do about 30cm. Next, line it with leftover greenhouse plastic. Then put down the perforated wicking pipes. These are just fairly large diameter PVC pipes with lots of holes drilled into the sides. They are about 20cm long, too. Then lay the irrigation pipe. This can be perforated or just slotted along the bottom. The inspection/refill bit allows you to check the level of the water in the reservoir. A normal wicking bed would just use boards or something for sides, but I’m going to use old tires because I hope to get them free and worms cannot escape easily (I dare them to try!).

Step 2: Wrong Way Wicking Bed

The pit then gets filled in. I’ll probably use river gravel because it is roundish and facilitates a large volume of water. The whole reservoir then gets a layer of shade cloth. This is to keep the grow media in the tires separated from the reservoir. It has to be pushed into the wicking pipes to allow the coir-based media to get down to the bottom of the reservoir. I think this is fairly clever, but I welcome any suggestions. Other wicking beds that I’ve seen just have a corner or two of the reservoir devoid of gravel so the wicking material can be fully immersed in the reservoir’s water.

Step 3: Wrong Way Wicking Bed

The tires can now be placed on the wicking bed with the wicking pipes at their centers. As the potato plants grow, more tires are placed on top and grow media added. Potatoes are cool; the right ones will just keep producing potatoes at higher and higher levels, to a certain degree. When the stack reaches about 3 layers and the plant decides that things are going tits up, just kick over the lot and separate the potatoes from the worms and grow media and start again. I could use water from the aquaponic system, but I probably won’t have to. With worms continuously feeding on the fish poo and producing castings, there will probably be enough nutrients in the media to support a crop to maturity. Carrots, radishes, and other such things can be grown this way, of course.

Upside Down Tomatoes

I've just got to do this. Wrong Way tomatoes!

This is a subject that caught my attention some time ago and was put into one of those dusty compartments in my brain. I was looking for information about growing things in micro-climates similar to the Bolaven Plateau. The Olympic Peninsula in Washington is one such place. Cool with lots of rain and little sunshine. There is a lot of debate about whether tomatoes (or bell peppers, for that matter) grow better this way. But there are certainly advantages. These include better air circulation, inaccessibility to creepy crawly things, and the use of vertical “dead space.” This photo is from an article about a guy named Dick Schneider. It makes for very interesting reading. I’ve emailed the publisher of this article as I’d love to get in touch with this fellow. Notice how he uses black pails. This heats up the media a bit which is good for tomatoes. A disadvantage is that the growing media dries out quickly. It’s also heavy, if ordinary soil is used, but I think my soiless grow media will be okay. I look forward to experimenting.

[TCLynx]

There has been some debate over the safety of using tires in the food garden.  You might want to research the leaching possibilities so you can make your own informed decision before you set your heart on them.

I like the idea of using tires filled with rammed earth or whatever as retaining wall and such but I would rather not have them in contact with the moist food growing media.

If worms want to escape, they will (or they die trying,) if you create a pleasant environment for them, they tend to stay even if you are not trying to contain them.

[Paul Smith]

I would like to see HARD DATA about the health concerns about using tires as a grow container.  There has been a lot of talk on other forums, but no hard data, just conjecture.  I know of people who have been using tire gardens for years and there doesn't seem to be any difference in their health or the quality of vegetables produced.

As a missionary to Haiti, I have been encouraging the use of tire gardens for years because tires are one of the few resources available, many times free or real cheap.

Thanks for the input and keep up the interest, Paul.
 
TCLynx said:

There has been some debate over the safety of using tires in the food garden.  You might want to research the leaching possibilities so you can make your own informed decision before you set your heart on them.

I like the idea of using tires filled with rammed earth or whatever as retaining wall and such but I would rather not have them in contact with the moist food growing media.

If worms want to escape, they will (or they die trying,) if you create a pleasant environment for them, they tend to stay even if you are not trying to contain them.

[Richard Mong]

I agree, Paul. Some people tend to flinch when they hear about growing food in recycled tires. I've done quite a bit of snooping around on the internet about the subject. If they aren't chopped into tiny pieces or burned, any nasty stuff is locked into the material. And the fact that they are old is an advantage too, in that anything that's going to leach into the environment probably already has. Doesn't that sound scientific? I'm in the "they're safe" camp.

Paul Smith said:

I would like to see HARD DATA about the health concerns about using tires as a grow container.  There has been a lot of talk on other forums, but no hard data, just conjecture.  I know of people who have been using tire gardens for years and there doesn't seem to be any difference in their health or the quality of vegetables produced.

As a missionary to Haiti, I have been encouraging the use of tire gardens for years because tires are one of the few resources available, many times free or real cheap.

Thanks for the input and keep up the interest, Paul.
 
TCLynx said:

There has been some debate over the safety of using tires in the food garden.  You might want to research the leaching possibilities so you can make your own informed decision before you set your heart on them.

I like the idea of using tires filled with rammed earth or whatever as retaining wall and such but I would rather not have them in contact with the moist food growing media.

If worms want to escape, they will (or they die trying,) if you create a pleasant environment for them, they tend to stay even if you are not trying to contain them.

[Richard Mong]

Hello TCLynx,

I've addressed the tire issue in my reply to Paul. I'm in the "they're safe" camp after a lot of research. Also, Laos is classified as a "Least Developed Country." The people here do not have the option of doing everything with food grade materials. Of course, if I doubted their safety, I wouldn't recommend their use, either.

Regarding the worms, I've had two worm catastrophes so far. My supplier in Thailand took responsibility for both. He had little experience preparing them for transport. I agree 100% that if you make them a good home, they will stay put. But for those times of temporary dissatisfaction, I think the slight overhang that a tire has will discourage them from leaving. This is what an Aussie ex-worm farmer told me over a large quantity of beer in my pub in Thailand, so I'm inclined to believe it. I've written a funny story about one of my experiences, "The Great Escape." It's here if you are interested: http://www.wrongwayhome.com/2011/12/the-great-escape/

TCLynx said:

There has been some debate over the safety of using tires in the food garden.  You might want to research the leaching possibilities so you can make your own informed decision before you set your heart on them.

I like the idea of using tires filled with rammed earth or whatever as retaining wall and such but I would rather not have them in contact with the moist food growing media.

If worms want to escape, they will (or they die trying,) if you create a pleasant environment for them, they tend to stay even if you are not trying to contain them.

[TCLynx]

Richard, I'm in the Camp of "Make your own decisions" and if you have done some research then there ya go.

And as for the worms, there are different types of composting worms and some stay put far better than others.  I've known of worm farms that panic if the power goes out since their method of keeping the worms down in the beds was to use bright lights over the beds and if the power went out at night the worms would all escape.  I like my worms, they might sometimes go wandering but my worm bins still have plenty of population so enough of them must stay put to keep them going.  My aquaponics is full of worms too, I must say I'm not quite sure how I feel about it when I find the reason for a tower feed being clogged seems to be the worm that has climbed into the plumbing.

[Richard Mong]

I'll be doing raft aquaponics so there won't be any in that component of my project, but I see no reason why they can't be in the raised wicking beds along with the potatoes and such. They help with aeration, I've read. Perhaps the worms I bought could sense that future generations of them would wind up as fish food. . .Then the poop from the fish would be fed back to them. Must be tough being a worm.

TCLynx said:

Richard, I'm in the Camp of "Make your own decisions" and if you have done some research then there ya go.

And as for the worms, there are different types of composting worms and some stay put far better than others.  I've known of worm farms that panic if the power goes out since their method of keeping the worms down in the beds was to use bright lights over the beds and if the power went out at night the worms would all escape.  I like my worms, they might sometimes go wandering but my worm bins still have plenty of population so enough of them must stay put to keep them going.  My aquaponics is full of worms too, I must say I'm not quite sure how I feel about it when I find the reason for a tower feed being clogged seems to be the worm that has climbed into the plumbing.

[Converse]

Greetings,

    Just wanted to let you know that you should have great success with your suspended buckets, growing tomatos and peppers.  Painting them black will do wonders for heating the growing medium inside.  Due to the differing micro-climates on the Olympic Peninsula itself, where you are referring to it may be pretty short on the sunny-days scale and high on rain, or statistically have more sunny days and less rain. Since you have referred to Dick Schneider in Chimachum, Wa., I figure you've done your research and know that is the area you need to look into for what grows in that climate.

   You can grow tomatoes and peppers in buckets.  I have even grown zucchini and crook neck squash in buckets suspended on the eaves of my coops and up in trees (as a way to keep the deer from getting to them).  My first season using buckets I grew using regular soil.  Next year I took medium from my worm beds. This was not completely yet worm composted.  I filled the buckets with what I shovelled out, worms, matter and all.  They did fine. Actually, they did fantastic! One thing I did not do was paint my buckets.  Some buckets were white, and some were dark green.  All unscientifically suspended up on eaves and in trees using baling twine (hey, this IS a farm here), no fancy hooks. The area I live in is just the west (wet) tip of the slope in the Cascade Mtn.s in the Columbia River Gorge in WA. (a micro-climate area too...a bit different from yours.... a bit harsher, I think).  Here is an example of what I did (photo):

 

You'll notice in the photo there is a yellow pear tomato plant with ripening tomatos on it growing out of the top of the bucket.  There is a squash plant growing out the side of the bucket (and petunias) and another tomato plant growing out the bottom..  The old electric cord on the tree is  re-purposed as a  clothes line.  And the photo also features one of many "forts" in our woods, complements of adventurous kiddos. The bucket was placed to take advantage of the sunny spot as well as to avoid deer.  I realize that when I used vermicompost to grow with including the redworms, I might be sacrificing those worms, but they kept the plants fertilized and the organic matter load in the medium helped retain moisture.

     Richard, sorry to learn of your ''worm catastrophies".  Don't give up. One thing you'll want to be sure of is that the tire stacks for the worms have adequate drainage and aeration, so the worms will stay put. There is a lady out here who I met at a farmers' market who told me she  keeps her redworms in stacked tires.  She told me that after she put them in there for one season, she killed them.  At one point they baked in the tires sitting in the sun.  She started over.  Then she found out that she needed to allow for the 'massive amount' of rain (her words) to we get to actually drain out the bottom and between the tires. That is the point at which we met. After I told her how to solve that issue, she has had success. It can work.  This is an area where people use what they have.  It is a matter of survival for many.  So I did not question her use of the tires.  It is what she had, and she was trying to provide for her family. People out here also grow potatoes in tire stacks.

 As TCLynx pointed out, some worms are more prone to wander than others..Make sure you know what kind of worms you are getting.  Some redworms require a lot to keep them home.  I am glad ours don't need lights and such to keep them home.  Our power goes off with regularity out here.

  I wish you the best on the project you are working on!  Keep us posted on how it all goes.

- Converse

[Richard Mong]

Hello Converse,

Thanks for the excellent feedback. The worms are a combination of

• Eudrilus eugeniae (common name: African nightcrawler);
• Perionyx excavatus (common names: blue worm, Indian blue); and
• Eisenia fetida (common names: redworm, tiger worm).

Tiger worms probably dominate. These were from an English friend who has a worm farm in Thailand. He's a retired civil engineer who thought he'd be able to convince golf courses in Thailand to switch to worm castings tea but it never happened. He's not been able to sell much of his worm castings, either, as the Thais think "more is better" and would rather buy a big bag of cow manure than a smaller bag of worm castings. His operation, though, is huge by my standards. He wasn't focused on selling the worms, though. After two rather tragic failures which I thought were my fault, he did a lot of trials on his own trying to keep the worms packaged and alive for up to 4 days. This is so he could post them through the domestic mail system (not stating that they are worms, as you are not allowed to post worms). His failures were as tremendous as mine and he took responsibility. So he'll replace the worms I lost, 10kg in all, whenever I'm ready to claim them. It's really a greater loss than that for me because when you figure how many I would have now, 8 to 10 months later, due to their exponential growth. . . well, you know what I mean. The root cause, which I suspected from the beginning, was that he packet them with copious amounts of cow manure. That, and perhaps too much water, not to mention an ambient temperature already threatening, caused the media to begin composting. The worms basically had a choice of escaping or being baked. Since they were OK the first night before I picked them up, he assumed they would continue to be OK, but the compost/heating effect isn't immediate, is it.

I won't have to worry about too much rain as the worms will be under roofing outside. I'll monitor temps and if the tires absorb too much heat, I'll protect them with shade cloth. I'm hoping that all their moisture needs will be taken care of through the wicking bed scheme and I'll be able to get away with watering them (from below) once a week or so. If you look at my system layout which I posted earlier, there are wicking potato beds on the left and wicking worm beds on the right. I'll try worms with the potatoes as I think both the worms and potatoes will survive being kicked over and harvested. With the worms-only wicking beds on the right, when one tire gets full, I'll put a layer of onion bag on top, then another tire, and keep feeding them. Presumably, the majority of worms will migrate up through the onion bag and into the next tire. Eventually there will be a moisture problem so if I want to continue going up, I'll probably have to top water them. But the beauty of this is that I hope to be able to slide off let's say the third tire and it will be mostly full of worms. Meanwhile, the two tires below will be mostly castings. Anything sound wrong about this?

Converse said:

Greetings,

    Just wanted to let you know that you should have great success with your suspended buckets, growing tomatos and peppers.  Painting them black will do wonders for heating the growing medium inside.  Due to the differing micro-climates on the Olympic Peninsula itself, where you are referring to it may be pretty short on the sunny-days scale and high on rain, or statistically have more sunny days and less rain. Since you have referred to Dick Schneider in Chimachum, Wa., I figure you've done your research and know that is the area you need to look into for what grows in that climate.

   You can grow tomatoes and peppers in buckets.  I have even grown zucchini and crook neck squash in buckets suspended on the eaves of my coops and up in trees (as a way to keep the deer from getting to them).  My first season using buckets I grew using regular soil.  Next year I took medium from my worm beds. This was not completely yet worm composted.  I filled the buckets with what I shovelled out, worms, matter and all.  They did fine. Actually, they did fantastic! One thing I did not do was paint my buckets.  Some buckets were white, and some were dark green.  All unscientifically suspended up on eaves and in trees using baling twine (hey, this IS a farm here), no fancy hooks. The area I live in is just the west (wet) tip of the slope in the Cascade Mtn.s in the Columbia River Gorge in WA. (a micro-climate area too...a bit different from yours.... a bit harsher, I think).  Here is an example of what I did (photo):

 

You'll notice in the photo there is a yellow pear tomato plant with ripening tomatos on it growing out of the top of the bucket.  There is a squash plant growing out the side of the bucket (and petunias) and another tomato plant growing out the bottom..  The old electric cord on the tree is  re-purposed as a  clothes line.  And the photo also features one of many "forts" in our woods, complements of adventurous kiddos. The bucket was placed to take advantage of the sunny spot as well as to avoid deer.  I realize that when I used vermicompost to grow with including the redworms, I might be sacrificing those worms, but they kept the plants fertilized and the organic matter load in the medium helped retain moisture.

     Richard, sorry to learn of your ''worm catastrophies".  Don't give up. One thing you'll want to be sure of is that the tire stacks for the worms have adequate drainage and aeration, so the worms will stay put. There is a lady out here who I met at a farmers' market who told me she  keeps her redworms in stacked tires.  She told me that after she put them in there for one season, she killed them.  At one point they baked in the tires sitting in the sun.  She started over.  Then she found out that she needed to allow for the 'massive amount' of rain (her words) to we get to actually drain out the bottom and between the tires. That is the point at which we met. After I told her how to solve that issue, she has had success. It can work.  This is an area where people use what they have.  It is a matter of survival for many.  So I did not question her use of the tires.  It is what she had, and she was trying to provide for her family. People out here also grow potatoes in tire stacks.

 As TCLynx pointed out, some worms are more prone to wander than others..Make sure you know what kind of worms you are getting.  Some redworms require a lot to keep them home.  I am glad ours don't need lights and such to keep them home.  Our power goes off with regularity out here.

  I wish you the best on the project you are working on!  Keep us posted on how it all goes.

- Converse

[TCLynx]

I know the stacking tray type worm bin idea seems sound but in my experience, worms will tend to migrate down or if you are top watering to keep the top food "tray" moist, the juices will trickle down and keep feeding plenty of worms down in the lower reaches so I've not found this method to be a perfect way to separate worms from castings.  What I usually wind up doing to separate worms from castings is.....

I'll lay a screen or sturdy shade cloth over another worm bin.  And I'll harvest out the worms and mostly finished castings/vermicompost from the nearly finished bin or section of bin and lay this on top of the screen in a nearby prepped bin with food under it.  this way many of the worms will migrate down to the moist food while the castings are allowed to dry a little but not too much in a top layer.  This makes them easier to sift if you are sifting them for use in seed starting trays or soil blocks or something and it greatly reduces the handling of the worms themselves.  Separating worms from castings by the spread on a tarp method  and making little mounds for the worms to go down to the bottom is very tedious, time consuming, and hard on the back hunching over little piles of castings on a tarp on the ground and scooping the tops of them into buckets and putting the worms into separate buckets to go back to the bins.

Now if you are simply going to use worms and vermicompost directly in the planting containers with no separation or sifting, then how you operate your worm bin and all probably won't make too much difference.  You may need more worm bin space than you have potato stacks though since all compost shrinks so to keep enough vermicompost going to be filling two stacks of tires you probably need at least 4 stacks of tires for vermicomposting and enough material to be feeding and using for bedding for the worms.

[Richard Mong]

Hello TCLynx,

Yes, my wishful thinking often gets the better of me. The onion bag trick was something I read about that they do in Cuba, were I suspect the worms are far more disciplined. As for me, I'm 6' 4" with a bad back from an old high school track and field injury, so I don't like the prospect of doing a lot of bending over. My Lao missus, however, is shy of 4' 10" and can squat for hours on end doing the most tedious of tasks. As a kid, I used to have other kids bait my hook. I'll let you all know how it goes. . .

Getting back to the gist of my post, do you see any obvious problems with my wicking bed design?

TCLynx said:

I know the stacking tray type worm bin idea seems sound but in my experience, worms will tend to migrate down or if you are top watering to keep the top food "tray" moist, the juices will trickle down and keep feeding plenty of worms down in the lower reaches so I've not found this method to be a perfect way to separate worms from castings.  What I usually wind up doing to separate worms from castings is.....

I'll lay a screen or sturdy shade cloth over another worm bin.  And I'll harvest out the worms and mostly finished castings/vermicompost from the nearly finished bin or section of bin and lay this on top of the screen in a nearby prepped bin with food under it.  this way many of the worms will migrate down to the moist food while the castings are allowed to dry a little but not too much in a top layer.  This makes them easier to sift if you are sifting them for use in seed starting trays or soil blocks or something and it greatly reduces the handling of the worms themselves.  Separating worms from castings by the spread on a tarp method  and making little mounds for the worms to go down to the bottom is very tedious, time consuming, and hard on the back hunching over little piles of castings on a tarp on the ground and scooping the tops of them into buckets and putting the worms into separate buckets to go back to the bins.

Now if you are simply going to use worms and vermicompost directly in the planting containers with no separation or sifting, then how you operate your worm bin and all probably won't make too much difference.  You may need more worm bin space than you have potato stacks though since all compost shrinks so to keep enough vermicompost going to be filling two stacks of tires you probably need at least 4 stacks of tires for vermicomposting and enough material to be feeding and using for bedding for the worms.

[TCLynx]

For growing the potatoes I think it will be fine since the potato plant only needs the moisture down by the roots so the fact that the wicking action will only lift moisture so far is fine for them.

As for the worm bin stacks, you are right that you will probably need to add some top moisture if your food additions and bedding don't bring enough moisture and you air is too dry.  But worms don't need a heck of a lot of water in moist climates so how well the worm stacks will work will probably depend largely on the heating of the tires in the sun, if they get too hot you may have issues but if they don't bake in the sun then I expect it will be worth the try.

[Richard Mong]

Thanks for the reply. I think I'll paint the worm tires white, and adjust the potato bins such that they can have or not have additional warmth. Sorry, got to leave it at that, as its late in the evening (Eric Clapton?) and the neighbors are infected with the Beer Lao virus, which I've subsequently contracted.  Best beer SE Asia.

Cheers!