keyhole garden in summer drought

Inspired by the keyhole garden thread, and my drive to make our farm irrigation free, I started making a new garden bed.  

Here's what it looked like at the start of today.


I used wattle (weaving) as the walls because we can see dismantling it in 4 or 5 years, and we wanted something easy to take apart.  Also, I like the way wattle looks.  

For the posts, I used old garden stakes.  Big mistake.  The wood was old and broke - frequently!  If I make another one of these, I'll cut down some trees, about 3 inches thick, sharpen them, dry them, and use them as the uprights.

I drew the circles and pounded in all the posts first.  After that, I wove the inside loosely with fruit tree prunings.  For the outside, I thinned the new forest near the pond and wove with willow, alder and cottonwood.  Since I haven't let these dry yet, I can foresee some of the willows might try to grow, but that's okay because I can use them to increase the height of the wall.  

Well, maybe one other problem.  Wattle doesn't hold soil very well.  But you know what does?  Roots!  So this morning, I pruned my herb garden and lined the inside of the wattle wall with herb trimmings.  Mint, sage, thyme, basil, mint, tarragon, mint, more sage, calendula, fennel, all sorts of herbs.  I have a theory that maybe some of them might grow through the cracks in the wattle, and by the time the soil works its way to the wall, the herbs will help keep it in.  I never said it was a good theory.


SPOILER:
This is how the garden turned out 5-years later.  I did say it would be temporary.  It's finally time to reclaim that patch and plant some more trees.

I put several layers of stuff in the outer ring.  The base layer was leaves, branches, and broken posts from making the wattle.  Also a bit of bedding from some duck houses I cleaned out last week.  

On top of that, I put spunky wood from an old maple stump.



I watered it with the hose, probably not enough.  Then I started layering pea straw and other garden waste.  I pressed it down with a rake and watered it some more.



Then it was time for a cuppa tea.

My goal here is to garden with little or no watering of the plants.  I expect about one to two litres of grey water will make their way into the compost pile each day, and hopefully, that will be enough.  If not, I can use the water the ducks make mucky to keep the compost pile moist.  

My theory is that it will absorb a lot of moisture during our winter rains.  Hold on to that moisture, and the grey water we add to the compost pile will just help keep it moist.  My biggest concern with the traditional brick or stone wall keyhole garden is that there might not be enough drainage.  Our winters get pretty wet so I don't want to deal with drowning plants.  That's another reason for the wattle walls.  

For the next layer, I cleaned out my geese and duck houses.  I used their bedding to fill in as many hollows and gaps as I could, watering and tamping it down at the same time.  

One of the problems I see is that my compost pile will dry out too quickly.  I made it 3 feet across, which might be a bit big, but we do make a lot of compost.  

To stop it drying out, I put a piece of cloth on top.  



I'm going to need to make something better.  A wooden lid like I had originally planned might be good for a 1 or 2-foot wide compost pile, but I think it will be too heavy for a three foot one.  Something woven should do.  I just need to look around the place and see what I can find.

So the center section will be a taller compost pile? That would leach nutrients into the surrounding bed during the rains. Do you plan to pour grey water into the center or around the outer ring? I hope it works well!

Mark Tudor wrote:So the center section will be a taller compost pile? That would leach nutrients into the surrounding bed during the rains. Do you plan to pour grey water into the center or around the outer ring? I hope it works well!

The big keyhole thread I linked to in the first post has a lot about how this garden works.  It's really popular in Africa as it makes it easy to grow fresh veggies in drought conditions.   Each day, the compost and grey water from the kitchen is poured in the centre where the compost bin is.  It is supposed to be higher than the outer ring and in many of them, the soil slopes upwards towards the centre.  

This is a pretty high maintenance garden for my farm, but I'm having trouble growing fresh greens due to too much drainage and lack of water.  Or summer drought starts about our last frost day and ends with the first frost of winter.  So I'm experimenting with different ways of growing crops with zero irrigation.  This one will have some irrigation, with the water from rinsing the compost bin going in the central ring.  I hope when I perfect our technique for low and zero irrigation growing, I can teach some of the other people around how to do it.  This might be a good kind of kitchen garden for urban dwellers, except in urban centres, there are bylaws to prevent open composting which attracts rats and racoons.  If this one works, I'll try making a more permanent keyhole bed where the compost is rat and racoon proof.  

r ranson wrote:  For the outside, I thinned the new forest near the pond and wove with willow, alder and cottonwood.  Since I haven't let these dry yet, I can foresee some of the willows might try to grow, but that's okay because I can use them to increase the height of the wall.  

You might want to check out the post about the "big mistake" willow fedge here: https://permies.com/t/63754/design-living-fence#545708

Short version: poster says her willow living fence sucked the nutrients out of her garden.

Yeh, the Willow worries me.  It's far too close to the well for willow to grow.  

But, I'm also confident in my ability to kill willow.  Willow and I have a history.  It's about the only tree I can reliably kill.  

I've built a couple circles with rock, for customers who wanted a raised bed that shape. These were laid up loose, without mortar. They definitely drain well, much too well. They have to be mulched and irrigated. Although winter rain is heavy, the issue is not drowning the plants, but preventing runoff from the bed from happening in only a few spots, and allowing soil to wash out. We tried to pack fine gravel and sand , into the inner portion of cracks, to provide a soil retaining screen.

I'll bet that the leaves of taller plants, will lean toward the open space of the keyhole. This would make it rather difficult to put a solid lid on and off, without injuring those leaves. Something done in two pieces, such as two rectangular pieces of plywood, that overlap a little, could provide a cover that is slid toward the center, before extraction. You might find that it's only necessary to remove a single portion sometimes.

For people in town, who want to have a covered composter that is somewhat vermin proof, they could simply insert their existing composter into the keyhole, leaving the rim a few inches above soil line. The bottom of the composter could be removed. The walls could be cut at whatever height desired. A big plastic tote bin, with the bottom removed, could serve the same function.

I think I'll weave an inner lid that sits on top of the compost pile.  Probably out of willow and grasses with a twining method.  a bigger version of what I did here.



I might also try making a thatched roof for half of it, something like in this video.  

https://youtu.be/ykCXfjzfaco

If I make a wooden lid, I would need something to rest it on, or I would need to make it un-circular like the hole.  I think basketry is going to be easier and less likely to compact the compost.

Watching the video again, I see that the compost circle size is a radius of 45cm (about 1.5 feet) which is the same as mine.  So maybe my compost bin isn't too big after all.  

Although, I'm curious why the North American instructions often have very small compost bins, sometimes only 6 inches across.  

I think the ones directed toward North Americans, are meant to be primarily kitchen compost disposal. The ones in Africa seem to use kitchen stuff and everything from the barnyard, in larger systems that are meant to provide a large portion of the family's food. Most of us in North America would still survive just fine if our garden failed. Many in Africa, would go hungry if their efforts failed, so they are putting a little more into it. I think some of the big ones are a community effort.

I have done a regular compost bin, with no bottom in it, at the edge of a garden. All debris from a family of four was thrown in there, and it never got close to half full. Worms from the garden migrated in and out at will, and they ate everything up. So it wasn't so much a compost bin as a vermiculture bin. But I did nothing to help those worms other than dropping food down the hole. No management whatsoever.

I like your idea of the plastic compost core for the urban version of this.  It's already fairly rat proof.  Maybe a few holes below where the soil will be to encourage water and nutrient flow?  Or maybe shape some fine mesh hardware cloth into the bin, with the top of an old compost bin and its lid for the above ground bit?  Or maybe an old garbage can.  I think this style of garden has a lot of potential in to improve family food production in our climate.  Afterall, some of the micro climates can go 6 months without rainfall in the summer.  

Dale Hodgins wrote:I think the ones directed toward North Americans, are meant to be primarily kitchen compost disposal. The ones in Africa seem to use kitchen stuff and everything from the barnyard, in larger systems that are meant to provide a large portion of the family's food. Most of us in North America would still survive just fine if our garden failed. Many in Africa, would go hungry if their efforts failed, so they are putting a little more into it. I think some of the big ones are a community effort.

That makes a lot of sense.  I'll be putting household scraps (the ones not fed to the chickens) as well as post harvest plant debris and some animal bedding.  I'm wondering if this is going to be a big enough pile to produce heat.

Done!



It took about a yard of soil to give it at least 4 inches (in some places almost a foot deep).  Very little soil fell through the wattle.  Actually, the biggest trouble was the central ring.  Next time, I'll stuff it full with stuff or line it with paper so that the soil won't fall through to the centre. I watered the soil well to test how it would hold up.  Places where I pounded the filler down the most, were the best.  With the filler taking up so much of the space, this garden could be as tall as you like, and still, take the same amount of soil.  Next one I would like to have waist high.  

There is one big challenge... well, four actually.  



Due to a coopers hawk, mum and three chicks are currently in the area where the veg grow.  They love digging (thus the dust cloud).  

A temporary solution which doubles as shade cloth for the plants.

Every layer but the last, got soaked with the hose when it went down, and just before the next layer went on top.  Everything in the bed should be very wet, except I haven't yet managed to make water run out through the cracks in the wattle.  For the top layer, I simulated a heavy rain with the hose to see if it would wash away anywhere.  From what I've read, the theory is, this is the last time I'll need to water the garden part except when planting seeds.  So long as moisture keeps going into the compost pile, some of it should wick out into the garden and if I stress the plants enough by not watering them, they will grow longer roots to seek out the moisture.  Seems a good theory to me.

It's a bit late in the year to plant fall veg, so I just put in some over winter beet and carrots, some mustard greens, some walking onions, lettuce, leeks and a good king henery.  I have some starts for kale and Brussel sprouts that need to grow a bit more before I can transplant them.  If this works, I can actually be eating my own garden greens again instead of letting everything die from not being watered.  

Speaking of not being watered - I found a cucumber today from a plant that hasn't had water since the end of May.  Seed saving for drought tolerance seems to be working.  

Just wondering, are you simply avoiding watering, as a proof of concept or are you actually that short of water? Are you on a low-flow well that could possibly go dry?

I find it amazing how much water some people will use, to produce an entire landscape of things that can't  be eaten.

I'm on a well and there have been a lot of housing and development up-watershed from me.  A lot of land re-shaping has moved the water to the other side of the ridge, and a lot of organic farming (heavy irrigation) has started up hill too.  It's starting to show.  We are careful with water.  Low flow everything. The well has run dry a few times in the past.  When we had it pulled for a new pump, it was a bit over 700 feet deep, so it takes a few hours to refill.  

But this project is inspired by more than that.  When I drive into town, I pass many of these CSA organic farms and all spring, summer and fall they are irrigating.  Constantly, usually with overhead sprinklers.  The last few summers the city reservoir got pretty low.  Low enough that if the fall rain hadn't come early, there would have been a stop all outdoor activities for anywhere that depends on that reservoir.  That means, no irrigation, no outdoor construction (because apparently, they need water to build stuff?), and a big long list I didn't pay attention to.  I can't imagine how many farms would fail if that happened.  But what if they grew half their crops with zero water?  That means less expense and more harvest.  More importantly, it meant that if they couldn't water, it would be insurance against crop failure.  With the housing boom and the extra demands on our water supply, coupled with the reservoir not filling up as much as expected each winter... I think there's going to be a big demand to find low and zero water gardening that actually works in our climate in the next five to 10 years.  I want to have it all sorted and figured out before that happens so I can be at the forefront of the water-free movement.  That way I can show what does work in our conditions and which drought farming/gardening methods simply don't work in our conditions.

I call our farm experimental because we are trying lots of different methods to see what works in our changing climate.  Some things like air wells have been a massive success.  Any forum of dew capture works well here.  With plant breeding and land shaping techniques, I can now grow sunflowers, amaranth, winter squash and several different pulses with ZERO water.  All but the amaranth now has some frost tolerance when young.  Looks like I might have my first success with zero-water hot peppers this year too.  My work with staple crops and zero water is coming along well, but what I lack are fresh greens.  I'm also thinking about groups that teach people how to garden, like our local seed library.  IF (big huge IF) this garden works, then it will be a showcase for teaching.  

What I don't know yet is how much water per day will it take to keep the central bit moist.  Maybe two litres?  

Ooooh, your weaving is lovely. Seriously, I'm sitting her gazing at your craftsmanship and hope one day I might make something half as good.

For stakes, I've been having a lot of luck using clumping bamboo that the previous owner planted. The stuff never gets to take over, because I'm always harvesting (and never having enough) for my projects. My old stakes get brittle after a year or two (due to all our moisture or because i don't try to cure them or because of the variety, I just don't know). If you don't have bamboo, it might be a worthwhile investment!

For keeping my chicken out of mine, I found just a two foot fence rising up from around the bed did the trick. I also put a little "gate" (a piece of fencing that put in front of the keyhole and remove when I need to access it). The fence around the edge does make it harder to access it, but since the bed is raised, it's not too much of a pain. I also only had one chicken, and there were a lot of areas for her to explore, so the fence was enough of a deterrent. I also kept the chicken from scratching in areas just by laying down 2 inch chicken wire on top of the bed , and that seemed to work pretty well, too. It worked really well if the fencing was kind of wrinkled and bumpy so that some areas were raised and inch or two off of the garden bed. Since I was reusing fencing, the bumps came about rather naturally. It wasn't too hard to weed or pick produce through the chicken wire, either. I'm hoping it won't be hard to take the fencing off once the plants have died out in the winter, though I won't know until winter just how much of a pain putting this chickenwire down is going to be...

Now that I've just about filled the centre with compost, I'm wondering what to do about it.  Will it go down naturally?  Will it keep going down forever somehow?

I'm going to dig up some worms from a manure like to get things started.  Hopefully that will help.

Nicole Alderman wrote:Ooooh, your weaving is lovely. Seriously, I'm sitting her gazing at your craftsmanship and hope one day I might make something half as good.

awe, thanks.

I'm happy with how well it worked out and how easy it is to make.  My very first functioning basket.  But I can see a lot of ways I can do it better next time.  

Now that I've just about filled the centre with compost, I'm wondering what to do about it.  Will it go down naturally?  Will it keep going down forever somehow?

My best guess is something in between. Organic matter keeps breaking down for a real long time, and add in some earth-moving critters and it might keep settling for many years. But I'm afraid the laws of physics mandate at some point if you add enough in, you won't be able to put more in. Seems like a good place to grab handfuls of compost for seed-starting once that becomes the case! I've never been in the position of having too much compost.

BTW this looks great! I may have to steal your idea of using willows to build up garden beds. Love the aesthetic and I have a ton of willow! (The previous name of the property is actually Willow Flats)

Hi R Ranson,

I'm in North Saanich and I did an experimental bed which I call ARK1, three years ago using packing skids as the uprights. I tried lining it with cardboard thinking that the plant roots would keep the dirt in in the long term after feeding on the cardboard. I under-engineered the central compost tube and it collapsed badly. Also, I was experimenting with a 30" high (75cm) bed which makes the whole process more difficult, but I've got arthritis and I want to be able to garden 15 years from now, so my rational was to start experimenting now!!
So the first try was not good, but I learned. Last fall I filled in the space between the inside and outside of the skids with any branches/scraps of wood that I could jam in and the loss of dirt is no longer such a problem. When I worked on ARK2 this spring, I broke down and lined the inside of the walls with landscape fabric - yes, it's not natural or biodegradable, but if it's not exposed to sun, it will last a long time.
Because I'm trying for a tall bed, I found that the compost moisture was too deep in the first attempt to help any but the most deeply rooted plants. The research I had done suggested some people put rocks in the bottom of the compost tube, but I found that hadn't helped. So when I re-built ARK1, I cut about 19" (49 cm) off the bottom of a salvaged plastic barrel, drilled drainage holes from the bottom to about 3" (8 cm) from the top just on the arc of where the dirt would be and not where the "keyhole" part is, and used a couple of old breeze blocks to set it on to keep the moisture nearer to the top of the bed. I find that barrels aren't as sturdy as they used to be, so I get old bike rims from the local bike shop and cut them to fit inside the rim to keep the barrel round. I salvaged a "lid" from a friend's broken patio heater. It is in a fairly shady location and is planted with kale, leaf cabbage and re-planted green onion trimmings and some lettuce transplants. The only thing that didn't thrive was the lettuce. It was just too attractive to the slugs and couldn't outgrow them. I had tried putting Khaki Campbell ducks on slug patrol around the perimeter, but a mink came through in the middle of the day and killed all four of them. I won't be able to try that again until I can experiment with some electric fencing. I picked green onion tops just two days ago, and kale for some stew a few days before that. I'm totally convinced that we can make this work in our climate and am *really* glad to hear that you're experimenting with the same concept.

The downside of the packing skids was not only the gaps, but the fact that one can't easily build it "round". So I changed my approach to build ARK2. According to what I'd read, 6' (185cm) is the "magic" diameter for plants to stay watered just through the compost. This was very difficult to manage with the skids. We've got lots of rock, but it's not the sort that dry stacks easily. I had been given a bunch of 20 liter buckets with lids. I painted 38 of them black, filled them with rocks, tipped the first 19 upside down on the edge of the 185 cm diameter circle I'd drawn in the dirt, and stacked the second 19 upside down on top of the first. I'd also salvaged some miscellaneous mis-matched concrete blocks that I used to make the entrance to the compost tube, keeping it as narrow as I felt I could to give the bed more planting area. I built the compost tube as described above, this time using the base of the broken heater - a *much* heavier, but still manageable lid. I filled the bottom of this bed with some rounds of fir we'd deemed too rotten to be firewood thinking this would act a bit like a hugel as well. I added dirt and compost and unfortunately some horsey doo doo. We had such a cold, wet spring, it appears that the horse shit was just too hot, and the only thing that has survived is the Daikon radish. My poop supplier is a Vet and I've never had problems with it before, but we will have to wait and see. I'm hoping this bed does better next year. Some reading I've done recently suggests that many layered built up beds do better after they've had a year to let the materials age.  

I'll try to post an update next year!

Kyle Neath wrote:

BTW this looks great! I may have to steal your idea of using willows to build up garden beds. Love the aesthetic and I have a ton of willow! (The previous name of the property is actually Willow Flats)

You can borrow the idea, it but only if you post photos for us to see.  

I assume that you have plenty of scraps when you're processing various fibers. A lot of that material could work to retain soil, if it were placed directly against the wattle. Stinging nettle, flax and wool could all hold back dirt. Hopefully this would allow the wattle to last longer.

Dale Hodgins wrote:I assume that you have plenty of scraps when you're processing various fibers. A lot of that material could work to retain soil, if it were placed directly against the wattle. Stinging nettle, flax and wool could all hold back dirt. Hopefully this would allow the wattle to last longer.

That sounds like a good idea for an experiment.  When I have had waste from textile work (which isn't all that often), I add it to the garden, either as part of a mulch experiment or dug into the garden.  I noticed that in the soil, wool and other textiles rot faster than most paper.  On top of the soil, wool takes a lot longer to dissolve.  As the lining of the wattle, it would be dryer than buried in the soil and possibly last longer.  Old straw and hay can take the longest if not heat composted.  For this one, I used a layer of herbs to coat the inside of the wattles and firmly packed the old animal bedding against the walls to prevent soil from seeping through.  I'm curious how long this will last.  From my other observations around the farm, I'm expecting some soil to seep through this fall, once the rains come, but not much after that.  But of course, this is just a theory - that's why I'm testing it.  

One could do a test with paper, cloth, and straw as liners for the bed to see which one lasts the longest.  

In this article there is a picture of an African Keyhole garden that is lined with cloth.  

I love this! I am very interested in trying to garden without irrigation, too. What a great experiment.

I'm thinking that, with the compost center being such a good size, it will create some heat. I'll be interested to see how this helps prolong growth of the plants into the cold season. Last year my new buried wood and organic matter beds created heat well into the cold season. I harvested my last tomatoes and zucchinis in October. Stuff just kept growing! And I think it was the heat from the composting beds that helped.

Well done!

I'm thinking about the life expectancy of this bed.  The organic matter I put in the growing section will eventually break down.  If the compost gets full, I can't add more to it without emptying some out - which isn't easy.  I'm guessing 5 to 10 years in our climate - which is very good for a raised bed.  Most raised beds I have had needed constant soil augmentation to keep fertile and good water retention.  

An idea: To extend the life expectancy, I made it so I could build up the walls and central section in the future.  I'm going to add mulch to the bed.  Usually, I avoid mulch as in our climate, it reduces dew collection in the summer and drowns plants in the winter, but this bed is different (mulch is wonderful in other climates, just not mine)  It has good drainage for the winter and with the shade cloth on it, it won't be collecting dew from the air.  So I'll build up the soil from above with mulch.  If I build a second bed like this and alternate which one I put the compost in (bed 1 for 6 months, bed 2 for the other 6 months), then I could dig out some of the compost from the centre after it's had a chance to decompose and use it as mulch too.  Then I would have room in the centre to add more compost.  

I don't know if that would work.  For the amount of compost we make, I think I would need four beds like this to keep that system going.  

What if you made some sort of little door/access hatch at the bottom of the compost section in the keyhole? That way you could reach in and pull out the composted stuff from the bottom, and keep adding stuff at the top. Might work . . .

Tracy Wandling wrote:What if you made some sort of little door/access hatch at the bottom of the compost section in the keyhole? That way you could reach in and pull out the composted stuff from the bottom, and keep adding stuff at the top. Might work . . .

oh... now that's an idea.  I wonder how I can incorporate that into the next garden.  It would be pretty easy if I used an old plastic compost bin, but natural materials?  Not sure. Something to think about.  

r ranson wrote:

Tracy Wandling wrote:What if you made some sort of little door/access hatch at the bottom of the compost section in the keyhole? That way you could reach in and pull out the composted stuff from the bottom, and keep adding stuff at the top. Might work . . .

oh... now that's an idea.  I wonder how I can incorporate that into the next garden.  It would be pretty easy if I used an old plastic compost bin, but natural materials?  Not sure. Something to think about.  

I suggest that by the time you need to remove some compost from the bottom, you could just cut out a few bottom layers of the wattle to pull it out then fill the opening with stepping stones or something to hold the compost in when you stomp it down.

I might be opening a can of worms here, but if you have hot summers and droughts periods, why are you rising your garden bed? The higher it rises above the ground, the faster it dries out. Is it because your soil is heavy clay and sunken bed would not function outside of drought period? Just curious ....

The whole bed becomes a giant can of worms, even if the soil beneath is rocky and too dry for them to thrive.☺
.....
Gardens like this have thrived in very dry parts of Africa. The center is a big sponge, that holds water. There will be some water loss through the sides, but it is watered from center, so that the wetter part of the bed is not exposed to sun and wind. Herbs and other plants can be rooted into the sides of the bed. That way the sun shines on useful foliage, instead of the container. I'm not sure if that's being done with this one. Mediterranean stuff that likes hot-dry, might be suited to this drier portion of the bed.

There's a picture of an African woman beside a lined bed. This appears to be a plastic tarp sort of fabric. It's pretty shiny and if it were cotton or some natural material, I would expect staining.
.......
In your initial post you refer to using steaks. Dogs and rats love eating steaks, that's why I prefer to use stakes, instead.

Richard Gorny wrote:I might be opening a can of worms here, but if you have hot summers and droughts periods, why are you rising your garden bed? The higher it rises above the ground, the faster it dries out. Is it because your soil is heavy clay and sunken bed would not function outside of drought period? Just curious ....

A few reasons why.

This is just one of many experiments I have going on the farm.

No one in the household is getting any younger.  Raised beds mean less bending down. Since this is an intensive system, I want to make it as easy as possible for people to use and maintain.  

In the past, I noticed that raised beds have fewer bug issues.

It's easier to keep a chicken out of a raised bed than a sunken one.

To stop the plants from drowning in the winter.  Most years it's warm enough to garden year 'round, except the soil gets too wet even without water retention efforts.

It looks good which urbanites like.

It works in parts of Africa which have more drought than I do.

It's a lead up to an hugelkultur experiment that I'm still trying to convince the household to let me try.

What Dale said.

The compost is heating up in the middle.  Very hot.


I need to make a roof for the compost soon.  I'm thinking something that is easy to remove.  

In some of the videos in Africa, they make cone shaped roofs, others have a slanted cover.  I'm leaning towards the latter.  

My two lids are both mild cone shapes and both have "handles" of sorts in the middle. My theory was that if we did get any rain, the cone would distribute it around the bed.

I've had a thought about the pictures of these beds in Africa made from dry stacked rock. R Ranson (or others), do you think this could be giving an "air well" effect to the beds, harvesting dew to the outside of the bed while the compost is fertilizing and adding moisture from this inside?  Has anyone read whether there's been any comparison between dry stacked rock vs other building material?  I may not have many of the right type of rock for dry stacking, but it might be worth collecting up the ones I do have if it would make a big difference. We certainly get a fair dew fall most nights in this climate and I've wondered how to capture more of it on a small scale.

Re: Why do it? I agree with R Ranson that many Market Garden Farms appear to pay no attention to water conservation in order to get a fast crop looking good enough to sell. It works, but at what cost?
One reason I'm experimenting is that surface watering encourages a lot more weeds and as much as some of those weeds are useful ones, when water is scarce, it's nice to be able to choose my weeds.  
A second reason is the time involved in watering. My property is surrounded by ~200 ft (60 m) tall cedars and fir trees. The few areas sunny enough to get a good crop are not ones convenient for dragging hoses to and remembering to both turn water on and more important turn it off! When I do need to irrigate, I prefer a slow drip for hours so it soaks in deep enough that it's not gone an hour later. Lots of time to forget I started it!
A third reason is that we are overdue for a major earthquake. Food will be enough of an issue if it hits and if much of our food is totally dependent on daily water, it won't have a chance. Wells can go dry after a bad quake and even if they don't, electricity will be out and generators take fuel (which can't be pumped out of the tanks without electricity).  With luck, this won't happen in my lifetime, but it's a back-ground reason I'm experimenting with low water techniques. I've also been experimenting with "fake it" olla pots, as has a biologist friend of mine and we've had good success. They still require water, but at least it's sub-surface so there's less evaporation, and the ones I'm using seem to be good for 3-5 days. I'm not worried if they go dry for a day or two in most applications I'm trying. The goal is to balance inputs - both labor and water - with production in an environmentally and sustainable way. If the plants near the outside of the ARK beds need a little extra water to produce, I'd be prepared to add an olla pot for the period they're growing fruit as an experiment for the future. At the moment I'm putting crops needing more water closer to the center.

Just some thoughts I've been mulling over while I garden this week!

One thing I noticed in Morocco was that, while it was "dry" meaning little or no rain during our visit, it was also very humid compared with home (arid to semi-arid Okanogan Highlands).
There might be some details to work out where climate (temperature, humidity, wind) could make or break a garden like this, as it drives the evaporation rate.  Non-permeable, non-wicking sides could be a key tool in those conditions, like the tarp/fabric in the photo.

R. Ranson, would you mind sharing some details of your climate in this thread?  Which side of the Cascades, or average rainfall by month, or anything like that?  I'm wondering how close it is to our conditions.

-Erica

From Erica:

sharing some details of your climate in this thread

We're both at the southern end of Vancouver Island. We're considered a "Mediterranean" climate with *very* wet winters with often months of heavy cloud cover, followed by very dry summers. In summer it rarely gets above 30C where I am, and generally cools off at night down to the mid-teens. We are very much an area of micro-climates. The local joke is not far off the mark, "If you don't like the weather, wait 5 minutes or move 5 kilometers."

Also, our weather is heavily impacted by the el Nino/la Nina cycles. Last spring I had Muscovy ducks hatching young in early March. This year our first successful hatch was the middle of May and it barely qualified as successful. I lost two hatches expected in mid-June because of weather fluctuations. It makes planning interesting! Part of my experiment with my ARK2 bed using rock filled buckets for the walls was to see if some thermal mass would help plants cope with our varied weather.

R Ranson is correct in stating that we usually reliably get good dew fall due to the daily change from high to low temperature. I need to explore more about how small scale air wells work to capitalize on that. That said, we've been getting over a week of high "smoke" clouds that have lowered our expected highs, warmed our nights and decreased our dew on some nights early on, but now that the humidity has built up, that seems to be going back to normal - as much as anything about the weather is normal here! I hope where you are there is not too much smoke. There have been some scary things happening in BC's interior and many of us have been following the fire reports with concern. How much of BC's fire troubles are the result of "weather weirding" and how much because humans think they're smarter than nature and planted mono-culture pine forests rather than polycultures?