Earth holes: A experiment in Guerrilla irrigation

High all! Since my Overgrow.com days I have had a mission, to develop a practical irrigation system for Guerrilla growers with the following attributes:

1.Ultra reliable and simple in operation: No Timers to malfunction, no valves that stick open or shut, no small pipes or drippers to plug.

2. Efficiency: As little water waste as possible, stretching the water you haul/store to the max, very important in arid climates and in grows with few visits.

3. Easily camouflaged: A system that is well hidden and not a beacon to the enemy.

4. Could be made to last multiple weeks between visits: This is critical to me for security, the longer between visits the further into the wilderness you can put your plants, making them harder to find. Also fewer visits means more difficulty for law enforcement to investigate you. Also the freed up time means you could care for more plants through the summer, than you could when watering weekly by hand. For me this will allow me more time with my family and doing my normal legit job, while still growing enough bud to smoke personally and enough to cover many of my critical bills(times are tough!).

Of course the trade off is more preparation work in the off seasons.

So my mission is a ultra-reliable irrigation system that can be developed to last 3-5 weeks between visits. This is a tall bill, and developing it will take a bit of experimentation, which I will start on this summer, my hope is to have a solid dependable system ready to use for 2010.
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At the end of my disappointing 2008 season I decided it was time to finally stop talking about this mythical system, and start developing it. My first ideas broke my rules concerning small tubes, and often compromised other mission goals.

This winter though, Silverback posted up his excellent thread concerning his Gorilla Collar, I was inspired by the Air-tight version and thought the principle behind it could be applied to a watering device designed for extending irrigation visits to multiple weeks.
After a bit of sketching I came up with the GSWD, which was also inspired by the Earthbox(a self-watering planter). At the heart of the GSWD was a soil wick which sat in a small reservoir of water, the wick helped the soil of the hole uptake water from the device through capillary(or wicking) action, as water was drawn from the soil by the plant, it was replaced through the Capillary action from the device.
The weakness of the device is it required a external air-tight reservoir to operate and refill properly, I found that building reservoirs with enough capacity to reach my 3-5 week goal was going to be too expensive because of the containers and fittings I'd need to accomplish a truly air-tight system.

After being forced to abandon the GSWD, I turned again to the Earthbox which had inspired it, and then was born my current idea, the Earth hole. Basically its a Earthbox that you can build on site in the planting hole.


First let me give a brief description of the Earthbox. The Earthbox is a self-watering planter that consists of a large plastic container split into two sections, the top part is a planter, it contains the potting soil, below you have a reservoir containing a supply of water. Extending from the planter section into the reservoir is a container allows the potting soil to contact the water of the reservoir, this soil wick is the heart of the system.
The Earthbox works by Capillary action, if you aren't familiar with this term please look it up on Wikipedia or in a search engine. Here is a link to Wikipedia explaining Capillary action- http://en.wikipedia.org/wiki/Capillary_action

Basically Capillary action is the phenomenon that allows wicks to work, in a oil lamp it draws the oil up to the flame through the wick which is made of a porous fiber. In the Earthbox the porous nature of the potting soil allows the same wicking action, as the plant takes up water and dries the soil, it draws more water up from moister soil below, and in tern the soil below that draws more moisture, ending at the water surrounding the soil wick, and as the plant takes more water the process repeats itself.

The other great thing about the Earthbox is that it is a closed system, because the soil and water are completely contained, drier soils and plants around the planter cannot steal the moisture, most of the water you bring is used by the intended plant.

The Earth hole​

My Earthhole is basically a Earthbox in operation, but instead of having a planter section made from a large cumbersome container like a tote or garbage can, it is built in the hole by lining the hole with plastic to isolate your planting soil from the surrounding drier soils. The remaining recognizable part of the Earthbox is the reservoir and wick sections, which are placed in the hole beneath the plant and refilled through a tube extending from the rez to ground level. The plastic lining is placed on the sides of the hole from top to bottom, leaving the bottom open to allow excess rainwater to escape, also the plants roots should be free to wander should they choose to explore.

My versions of the Earth hole will use large wick/reservoir devices since I am trying to develop long lasting systems, they could take much smaller forms. Installing them will take a bit more digging than for a normal planting hole. Also the materials I am using will be low quality and cheap, this is due to these being experimental, no use making it to last if I don't continue using them. If the idea is proven sound, I'll develop much more durable and efficient designs based on my experiences in the 2009 growing season.

I am posting this idea to share my experiment, I am in no way encouraging anyone to build these and depend on them for growing yet, but if anyone would like to experiment with a couple please do and let me know how they work for you. I have no real idea how long these will go between refills, it could be a couple weeks, it could be a month, its possible these won't work well at all, I just don't know!

OK, I have two basic designs, both should cost between $5 and $10 to build, one takes a bit of wood working and time, the other could be built 5 minutes.

First we have the higher investment model:

This version is built from lumber, I used 5/8" OSB panel(plywood could be used instead), 1"x2" boards, and a 2 gallon bucket(a planter could be used here, or sections of pipe), this will contain my soil wick.


I started by sawing up my lumber:
2- 18"x18" pieces of OSB
4- 18"x9 3/8" pieces of OSB panel(they are 9 3/8" wide because the bucket is that tall)
4- 18" long pieces of 1"x2"
4- 14 1/2" long pieces of 1"x2"
12- 5 7/8" long pieces of 1"x2"


Starting with one of the 18"x18" OSB pieces, I place the bucket upside down in the center, and draw a line with a pencil around the lip of the bucket. This piece will be the top or lid of the device.


Now I cut a hole inside the circle, leaving a 1/2" or so of wood inside the line, this is needed so that the middle of the device lid is supported by the bucket.


Now, using a small bit I drill lots of holes all over the bucket, this is so the water can reach the soil wick inside.


Now its time to build the sides, I start with a 18"x9 3/8" piece of OSB, 2-18" 1"x2", and 3- 5 7/8" pieces of 1"x2".


Using 2" screws I attach the 18" boards to the OSB as shown.


Now I mark the opposite side of the OSB at 9" with the pencil.


Now I line up the 3 shorter pieces of board between the longer ones I already attached, using the tape measure to center the middle one at 9". I flip the board over and put 2 screws in each, using the pencil mark I put on earlier to line up the screws on the middle piece.

Another piece like the one above is done in the same manner.


Now I will do two more side panels, these will be done slightly different. First I measure and place two lines 1 3/4" from the ends as pictured, do this on both ends, top and bottom.


Now I place two 14 1/2" long pieces of the 1"x2" between the lines, and put one screw in the middle of each.



Now 3 of the shorter pieces of 1"x2" are placed as shown and screwed in. One more panel just like this is built as well.


Now that the four sides are built, its time to put them together. Take one of the first two panels built and one of the two last panels built and butt them together like shown, put 3 screws through the OSB of one panel into the 1"x2" of the other panel, don't put the screws into the OSB of the other panel, the OSB will not hold the screw as well.


With all sides attached you have a wooden box with no top or bottom.


Now taking the 18"x18" piece of OSB without the hole in the middle, center it on the box, and put screws through it into the 1"x2" frame of the box.



Now using some sheet plastic, I will line the inside of the box so it will hold water, a 3' 6" piece will fit nicely in this box.


As I work the plastic into each corner, I use a stapler to secure it to the lip of the box, trying to be as neat as I can as I fit it all in. Once this layer is done I'll do a second just like it for extra insurance.



I am afraid of the bucket and fill tube poking a hole in the plastic lining the box, so I put a layer of heavy fabric in the bottom to protect it.


Now I place the bucket in the center of the box as shown.


I lay the lid on top of the box, centering the bucket as shown, I put four screws through the lid as shown so that the bucket won't be able to slide out of place. I secure the lid down as I did the bottom with screws.


Now its time to make and install the fill tube. I made mine from 1 1/4" PVC, any size pipe you can use for filling easily is suitable for this part. You will need to cut the pipe to near the same length as your hole will be deep, the hole I dig for displaying my devices is 2' so this is the length of my pipe.

I drill holes in one end of the pipe up to 9", since my box is 9 3/8" deep.

The hole for the fill pipe should be made before you attach the lid, make the hole just big enough so that the pipe will fit through leaving a tight fit that won't allow soil to drop into the box when buried.


Here is the box nearly completed.


I'm concerned about soil working its way through the holes in the wick and filling my rez, so I made a screen from a old T-shirt by tying the neck and sleeves shut, and installing as shown, with staples.



And here is the box placed in a 2'x2' hole, the sides are lined with plastic, and the fill tube extends just to soil level, where it can be plugged and buried in the soil of the hole.

The version I just showed is a bit of work to put together, but I want to experiment with different designs to find my final working model for 2010 and beyond. This model will hold at least 10 gallons of free water according to my calculations, which is my minimum capacity for testing this summer.

1.5'(18") wide
1.5'(18") wide
x0.79'(9 3/8") deep
------------------
1.77 Cubic feet
x7.5 Gallons per cu ft
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13.25 gallons
-2 gallons(for the wick)
----------------------
11.25 gallons of water





This is the quick and easy version, it took 5 minutes to build my prototype. Basically its a 5 gallon bucket drilled full of holes sitting in a 18 gallon storage tote, a fill tube extends to ground level. The Tub and Bucket are placed on the bottom of the hole, and filled as soil is placed back in the hole.


First you drill a bunch of small holes all over the bucket, also drill a hole in the lid for the fill tube which will be the same basic tube used in the first model shown here.


And here is the Tub and Bucket in the same hole I showed the first model.

This device will hold 5 gallons of free water inside the bucket, and also the soil in the tub will hold at least another 5 or more, bringing it to my minimum capacity this season.

This is a rough and ready version of my idea, and will lend itself well to various sizes and configurations, much smaller versions could be built for smaller applications.

The first concern I could see a grower having is the possibility the devices could keep the soil too wet, this should not be a problem since the soil can only take what is needed by the plant through the capillary action, the soil will not be able to soak up enough to lead to soil saturated enough to cut off oxygen to the roots. But as I said, this is a experimental idea, I have seen no one on the web anywhere attempt this, so we will see this summer.

Another concern is getting enough soil capacity without digging a absolutely enormous hole, I mean here you are digging hole not only for a plant but for a buried irrigation system. The hole I dug for displaying the devices was 2 feet deep and 2 feet wide, when you work the math on this it comes out to (2x2x2) 8 cubic feet, 8 times 7.5 gallons per cubic foot is 60 gallons.

60 gallons
-15 gallons for the plywood Earth hole device(approximate)
-----------
45 gallons of soil left for the plant

60 gallons
-18 gallons for the tub and Bucket
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42 gallons left for the plant

This seems like enough space to grow a pretty big and nice plant provided the soil quality is good, and well fertilized.

Another concern of mine is that the device may not work well with all soil types, particularly sandy soils, or other super well draining soils may not suck up moisture well. In these situations I would add lots of peat moss to the hole to aid in moisture up take, a matter of fact I intend to put lots of Peat moss in the soil when using these devices in all soil types, just to ensure good Capillary action takes place.


A final word for now:
As I said above, these devices are experimental , I have no idea if they will positively work as I have intended, I already plan to have alternative irrigation plans to put in action should the devices fail. I would repeat my warning to anyone who wants to try these ideas to only do it as a experiment, and do not put your whole crop at risk.

If these do work well for me, I will come up with a final design based on my experiments in the 2009 season. The final device will be built from durable materials, as I intend to find permanent plots I will use year after year, only digging up the devices to clean and maintenance as needed. For this year I am making them cheap, and placing them in plots I may or may not use next year, thus the lower investment and crudeness of my examples here.

Reserved by BACKCOUNTRY

i dont understand where you will be having the plants rootball, in that bucket??

Nope, in the soil above the device..........

BACKCOUNTRY said:

Another concern is getting enough soil capacity without digging a absolutely enormous hole, I mean here you are digging hole not only for a plant but for a buried irrigation system. The hole I dug for displaying the devices was 2 feet deep and 2 feet wide, when you work the math on this it comes out to (2x2x2) 8 cubic feet, 8 times 7.5 gallons per cubic foot is 60 gallons.

60 gallons
-15 gallons for the plywood Earth hole device(approximate)
-----------
45 gallons of soil left for the plant

60 gallons
-18 gallons for the tub and Bucket
-----------
42 gallons left for the plant

This seems like enough space to grow a pretty big and nice plant provided the soil quality is good, and well fertilized.

Click to expand...

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One thing I want to make clear is that the device in the Earth hole is not a buried planter that the plant grows into, it is a wicking device that distributes water far into the soil of the hole. I'm sure the plant will grow roots into the devices, but this is not meant to be the primary action of watering, the devices should moisten the entire root area of the plant.

Innovative...
Too bad bedrocks like 3 feet down here, sometimes less.

I wonder how long this would extend the time needed between site visits.

ahh. okay so will you be using just the soil as a wick? maybe using peat based soil to fill it?

amazing idea, this could be life-changing for hundreds of growers. I must admit i do not have the time or commitment to one plot to make this, but i can see it as being an awesome long term watering device. Back country, you are the best at what you do, keep it up and ill will be right along side you following your progress.

T-type- You still have enough room for this if you were interested.....

smokeymacpot- Yes, yes. I will be adding lots of peat moss to these holes to aid the wicking process.

CannabisBlunt- Thanks man.

i think peat and water cyrstals

Interesting

Interesting

idea BC!..........will be thinking on this one.

smokeymacpot- I'm actually afraid water crystals may be too much............. water crystals are used for holding moisture for use later, with the Earth hole you shouldn't need that, the only place I'd consider using them in a Earth hole would be in the wick its self, they really have no place or need anywhere else in the hole.

Thanks Hindu Killer! I'll be thinking on this one for many months until my experiment proves this idea has merit or else is a flop. I wouldn't put this much effort into it unless I thought it had a pretty good chance of working, but like I said this hasn't been done before to my knowledge, and I may find out why around July when the really hot weather sets in, or else I may have the answer to a personal problem I've been searching for for years.

I have not worked out my final soil mix yet, but it will include lots of Peat moss, maybe 50% of the soil in the hole. I'm going to go back to Organic growing this season, so the mix will be will be very rich with Manures and Compost, I won't add any drainage components because the soil on the ridge line I plant on tends to be pretty well draining on its own

I have several areas I'll be scouting soon, some have creeks to use near by, some I'll need to store water at during the rainy season(right now), and some I'll deliver water by car.

My plan is to check every 1-2 weeks through most of the season, if the Earth holes handle the first half of the Hot/Dry season well, I'll extend my visits to 3 weeks. Next year I hope I'll be able to extend visits to 3-5 weeks

Beautiful

Beautiful

Great stuff BC. Always an inspiration the stuff you come up with.

I notice in both designs you have a fairly large single wick. Would multiple smaller wicks work as well? To clarify, I'd like to use the tub as you've used the wooden box up above. I hope to achieve this by using multiple 3" PVC pipes (5-6, possibly more) as wicks. They would have to extend from the lid to the bottom of the tub for support, probably connecting to the lid with flanges.

This way the tub can hold the water (18 gal before the wicks are inserted) and the pipes would be filled with peat based soil of choice. In principle you get more wick surface area with multiple smaller wicks than one large one, I just don't know enough yet to know if this is a good or bad thing for the present application.

In any case, I hope to be trying one of these models this year. K+ to ya, great effort, illustration and explanation.

I'm in for this one, looks like you've thought it through.. and it WILL work. I've never considered using soil for a wick but I used a piece of cord in the past which worked well.

Lt. Herb, the PVC tube isn't a wick, it's a way to topup the res and check water levels. The soil in the bucket is the wick. If you wanted multiple wicks, you can use some pieces of wick or a cloth that wicks, and run them from the soil wick to various places within the soil bed to improve distribution. Once the plant reaches the soil wick, that will be irrelevant anyways.

wonderful idea, ill have to think logn and hard about thses!

I get that the PVC in BC's design is just a fill tube. My question was in regard to modifying the setup to be a bastardization of the two versions that BC posted up. My theory uses the plastic tub in place of the wooden box, and multiple 3" PVC tubes filled with soil in place of the bucket (strategically placed to keep the tub from imploding when buried).

The function of the larger PVC tubes would be to support the top of the tub and to provide more wick surface area as opposed to a single bucket. This, in theory, allows for more free water in the system as less volume is consumed by the wick in the reservoir while maintaining the same (or more) wick surface area for capillary action to occur.

Lt. Herb- Yes, using multiple wicks made from large pipe will/should work as well as the 2 gallon bucket I used, my original drawings when I was brainstorming this usually had a pipe wick in each corner of the box, with one more in the center. I used the bucket because I have tons of them scavenged from a local restaurant. I actually could see a significant advantage using multiple wicks, since contact with water would occur in all parts of the box, rather in one large area in the middle, it may lead to more even moisture content through all the soil.

I should also mention that anyone interested in my Earth hole should also study the Earthboxes, since it is basically the same beast. The original Earthbox has spun off a multitude of homemade copies, it seems like each builder has their own shape and size. Seeing this DIY phenomenon that surrounds the Earthbox helped give me the confidence to move forward with the Earth hole project.

Cascadia has a wonderful thread with tons of links concerning the Earthbox here- http://www.icmag.com/ic/showthread.php?t=106418

Lt. Herb said:

I notice in both designs you have a fairly large single wick. Would multiple smaller wicks work as well? To clarify, I'd like to use the tub as you've used the wooden box up above. I hope to achieve this by using multiple 3" PVC pipes (5-6, possibly more) as wicks. They would have to extend from the lid to the bottom of the tub for support, probably connecting to the lid with flanges.

This way the tub can hold the water (18 gal before the wicks are inserted) and the pipes would be filled with peat based soil of choice.

Click to expand...

After I reread your first post I noticed something, it seems you are thinking about using a 18 gallon tote(tub) instead of the wooden box I used?

There is a reason why I didn't use a plastic tub for the box part, that would have been easy, but there is a reason why I used a wooden box.
Basically try to imagine how heavy 30-40 gallons of soil is, now imagine it sitting on top of your earth hole device. There is no way a simple plastic tub will take that weight, even reinforced with the wick pipes the tub will crack and crumple, and/or the sides will be caved in by the soil on either side, reducing water capacity.
For the box design you have to consider the weight of the soil.

For the Tub an Bucket you are supporting no lid, the sides of the tub don't have to support weight, and since the tub is filled with soil, caving in shouldn't be a problem, the bucket will take the weight like a champ.

The problem of weight made the box design harder to build, which is why I am going to build and test the Tub and Bucket, just in case that design will work just as well, plus I figured it would be easier to implement for growers who just want to experiment a little with the idea.

Lt. Herb said:

I notice in both designs you have a fairly large single wick.

Click to expand...

LOL! I just read you post again, and need to address this line. Are you thinking the Bucket in the Tub and Bucket is a wick? Its actually a reservoir for containing free water, and for monitoring the level of water in the tub. Soil filling the tub and surrounding the bucket will be the wick, a very wide surface area.



I added this drawing to help explain how the tub and bucket works.

Very nice! It does effectively eliminate, or else use more effectively the large plastic containers usually used in Earthboxes. Has me thinking I'll have to try this instead of a traditional Earthbox this summer.

Hey BC. We're going to get there and your moving the ball down the field.. I like the concept of the earth hole and I know it will work. Its caused me to go back and look at my approach to see if there are applicable considerations for me.

With some enamel paint, that osb box will last for several years so for those growers that use the same plots each year, the minimal investment of money and labor is up front but for the consecutive years there would be very little effort or cost involved. It looks to me like you may have 5- 7 $ per hole up front? A grower can install 10 of these for the cost of a single pack of beans and if they were built and installed during the off season the labor requirements would be spread over time which is easier.

When i tested trial devices inside of a rubbermaid tote, the soil did become saturated. I felt at the time that to continue down that path, I was going to have to devise a way to control the amount of moisture leached from the water source either through smaller holes, a smaller wick or something, but I felt like controlling the release of the moisture was the answer.

Mountains are moved at one shovel full at a time. Lets keep digging.