The ultimate no water garden, coming soon

So, my urban farming group needs to figure out a way to grow food with no water use in Denver, CO, USA.

For those who don't know, Denver is a high plains Desert. It is a mile up, so it is missing a mile of atmosphere. As a result, it has an intense sun, and hot summer days, and even warm winter days, but is quite cool at night even during the summer. There is almost always a wind. We get only fourteen inches of precipitation, and to make it worse, most of that comes either as snow in the winter which sublimates away into the dry air, or as brief intense rain showers which hardly dampen the soil and then evaporate off. Occasionally, we get several inches at once in heavy storms which causes flash floods along the creeks. Most of the time it is sunny.

Throw in heavy thunderstorms with high winds and heavy hail, and and the fact that spring and fall are simply erratic mixtures of Summer and Winter, and you have a very intimidating climate. Add some heavy, sticky clay soils with a very high PH that bounce a pickax off, and prevent roots from moving deeper for water, and you have a gardener's nightmare.

What I hope to do is use a backhoe and dig a three foot wide, three foot deep trench. Then I will add lots of buried wood, hugelkultur style, and top it with soil. On top of the soil goes some mulch. Over the mulch goes a basket work pattern of bricks. These perform the same function as a rock mulch, but are more plentiful here. Set into the bed here and there are some ollas. The surface of the bricks are just below the surrounding soil. The extra soil from the hole is piled up to make a raised path sloping gently into the bed. It is covered with plastic with sand or gravel over the plastic to protect it.

The idea is that the loosened soil and wood will allow plant roots deep down, while the brick will convert light rains and snow into substantial flows of moisture that will penetrate the ground. Meanwhile the bricks keep the water in and moderate the micro climate. The ollas get filled with rainwater only a few times a year.

Any other ideas to add? Hopefully we will start construction soon, and I will document their progress here.

Yes. In Oklahoma we have this quasi desert that resembles your climate. Plus, I simply hate watering. Hugels are the best bet for drought-proofing outside of appropriate earthworks.

I've built several beds, some small and some large. I find it needs to be "innoculated" with every bit of good soil, amendments, fungi and all the other good microbes. I do this by scooping up decades-old leaf litter mold along the fence line (sorry, if you don't have this), grabbing handfuls of silt and dirt from around the various tree species (where I know different fungi exists), adding bonemeal, bloodmeal, calcium from various organic sources like powdered egg shells or epsom salts and the rest that you are probably aware. Not massive amounts, but take the time to throw in a little bit of everything. Only innoculation is necessary, similar to adding nitro to fuel a compost. The microbes will use it, take it up, chew it up, poop it out causing regeneration and the fungi will spread. They will do their thing.

Be certain to use well-aged wood amongst that which you build it with. Like really rotten wood. You want to imitate the type of aged wood that would grow mushrooms in a damp dark forest. Not all the wood, only some. Using all well-rotted wood means you'll need to rebuild within a year. The older wood starts it, the green wood makes it last.

It might be best to place the old wood into a bucket, or some large vat of water until they are completely saturated only to remove them right at the time you are to stack, build and cover so as to avoid them drying out. They must be wet and if your wind is like ours (probably worse), you'll need to take extra steps to ensure it is good and soaked right before you bury it.

Add other materials right along with the wood just as if you were building a compost pile. Toss in your lawn-trimmings (if you have any) or weed cuttings or crop cuttings, kitchen scraps before you top it with soil. Add a shovel of soil here and there as you build it to help innoculate. Make it as rich and diverse as you can. No science, just intuition. Whatever is "good" in your environment needs to be thrown in there for good measure. Give the microbes every type of food you can provide and they'll be very happy.

These details have proven to be a mighty force for my hugel beds. Those I slammed together hastily without tending to the details simply did not have as much moisture retention.

A good hugel-bed (for me, anyway) is great, but the top 4 inches can be relatively dry for my shallow-rooted crops. Just FYI. Mulch helps. I hate watering. Did I mention that?

My first hugel bed was built with great care and detail in the spring of 2011 in Central Oklahoma. That year I cried as I watched the lawn grass die off fully. it had been three years since the last fall with real leaves ... the dried colorful leaves. The trees were defoliating in August to conserve energy omitting the rich nutritious leaves in the fall. The local climate was turn from a temperate zone to a desert. I watched in amazement as the silt and top soil turned to SAND. I thought we would revisit another dust bowl. The climate was so hot and drastic that August we snatched up our tiny little girl and hauled off to a cooler, wetter state until the following January. When I got back, the deep-rooted plants in my hugel bed were still growing. The top of the plants were frost burnt, but the roots were alive. The beds tricked them into thinking winter never arrived. Later, I watched in amazement as the climate returned to normal and the drought receded.

The hugel beds are perfect for you hot days and cool nights. The root zone will hardly know the difference.

Not but once did I ever water that hugel bed and the crops did terrific. Now, I'll even build shallow hugel beds for my summer crops, like tomatoes that are placed far out of convenience. I never water them. I never amend them. I never feed them. I get tomatoes all year long and they never drown nor lack for water.

LOVE hugelkulture beds. Hope this helps.
bon

My entire vegetable garden has buried wood and deep mulch and unfortunately, I still need to water to grow normal crops. I think I could probably grow some special food crops with no watering if I were very careful with my choices, but I could not grow normal vegetable garden crops.

I think it is a worthwhile endeavor for you to try! Please keep us updated on the crops you select to grow, and how they respond to the no-water garden.

Clay is a challenge, for sure. From my experience, I would say that if you seal over the surface of the soil with the bricks, you will create a predominantly anaerobic soil environment, with disastrous consequences.

The biggest challenge with clay is maintaining the water/air balance in the soil. The rotting wood will help to create air space in the soil, but too much air is worse than too little, if you can believe that.

Maintaining healthy capillary channels in the soil is the most important task with clay soil. The soil needs to be able to breathe, literally.

Hello Adam,

I am hoping that the combination of a basket work pattern of bricks, maybe 50 percent open, and a lot of woody material in the soil would keep it aerated. What do you think?

And I know too much air can be a problem. When I build the hugelkulture part I will layer dirt into each layer of wood, to fill gaps.

In a simplified form, the problem I have is that the availible water just stays around on top until it evaporates, either because the ground does not absorb water fast enough in a heavy rain, or because the rain is light and only dampens the surface. I'm hoping the bricks will help with that. I've noticed that weeds seem to do well in cracks. But of course weeds are not crops.

And I will be testing different variations. Maybe different percentages of brick would be a good thing to test.

Do you think cobbles or gravel would work better?

I intend to do this at least in a rough scientific manner, with a rain gauge, weights of produce, etc.

Tyler;

That does not sound so good. How many inches of rain do you get? Do you know what the evapotranspiration rate is? And when and how do you get your precipitation?

Bonnie;

Thanks for the advice. I do have some really crumbly rotten wood, from the inside of an old cotton wood. However, I'm going to have to use mostly newer wood and wait a few years for best results. I intend to add lots of amendments. Also, about the top few inches being dry; I hope the bricks will solve that, but we will see.

Do you know how much rain you get in a normal, non drought year? Are your shallow hugel beds above or below ground?

Gilbert, you're right. Above or below is important. The best success is below ground because its heavy clay and dries so quickly. The hugel doesn't last as long with underground as I have good biodiversity that is starving for nutrients, but it's certainly worth the digging. I have one that is 5 years old and needed replenishment, but the soil is awesome as is. Above ground does dry faster, sometimes like a potted plant until it's good and ripe after a year or so. I do most of mine below ground and keep it mulched so it will just turned into well amended soil. We receive approximately 38" per year. My beds are on a gentle slope unsheltered from the wind which contributes to moisture depletion. I'm changing this, now. With the rain we have and earthworks and more trees, I'm aiming for a self-sustaining quasi tropical micro climates.

hat's off to ya for living in the desert. I'd pull my hair out.

Also? Hugel is a snake magnet. It's a good sign that it's working, but a drawback.

Gilbert Fritz wrote:

That does not sound so good. How many inches of rain do you get? Do you know what the evapotranspiration rate is? And when and how do you get your precipitation?

Average rainfall is about 28 inches but we've been in a drought for years, with averages closer to 15 inches per year. Rains mostly in Spring and Fall, with high temperatures in the Summer, 90 - 100F. Flooding rains perhaps once a year. Generally low humidity.

I should add that making this buried wood garden has enabled me to grow through the hot Summer, which I was not able to do previously in my old exposed regular dirt garden. I was simply not able to water enough to keep the plants alive through the searing season, what we call "the dead of Summer." So even though it was a crapton of work, it has been worth it.

I've been doing lots more thinking and researching on this, getting a test idea set up for next year.

First of all, this fits into my big urban sustainability experiment, see link at the end of this post. Basically, I'm seeing what I could do on a vacant lot where I have not guarantee of long term control, with no water source, and with only salvaged materials. (Though I will add some fertilizer.)

What I think I will do is leave the hugel component out for now. With the soil I've got, we really need an excavator. And I want this to be cheaply replicable by people with virtually no resources. Also, the site I can use for the experiment would be problematic to bring an excavator into.

(I did put in a shallow sunken hugel elsewhere with a bobcat excavator, but given its location I think it will eventually be fruit and nut bushes, not a dryland garden experiment. )

I will also experiment elsewhere with the ollas, since I want a truly no irrigation experiment.

So the experiment is as follows:

I will use two 4 foot wide, 50 foot long beds. One of them will have a line of sloping pallets laid out next to it, covered with a sheet of plastic, to double the catchment area. The other will not. Both will be slightly sunken with slightly mounded paths around them for water retention. In each bed, I will have a five ten foot sections of different kinds of mulch; one of basket weave brick, one of cobblestone type rocks, one of smaller gravel, one of wood chip mulch, and one of grass clippings. In the beds I will plant tomatoes, beans, and squash. I will choose dry land tolerant varieties of each. I am not including exotic dry land crops like quinoa, amaranth, or even heirloom flint corn, because I'm hoping to be able to grow more familiar crops with this amount of intervention. Each mulch strip will contain one or two of each of these plants. Tomatoes will be transplanted, beans and squash will be pre soaked. If the weather is dry and warmish in February as it usually is, and I get the beds built, I will plant an early cover crop in each that will be chopped down and covered with the mulch strips in June. Probably a mix of tillage radish, Austrian peas, and mustard. This will use up some of the water in the soil, but at the same time, will fix nitrogen and open the soil up. However, I am not sure if this will happen. So far the winter has been fairly wet, and the soil may be too wet to form the beds until May. (It does not take much water to make my clay soil unworkable; we generally get a couple of inches a month in March, April, May, and June. That is when most of our rain and snow falls.)

So what we should get is the yield of squash, tomatoes, and beans under five different types of mulch and with or without additional catchment area. I may give each tomato and squash plant a bit of liquid fish fertilizer in August with a leaky bucket, but otherwise I will not water at all. If it is a total loss, that is OK, since I am not counting on it. And if it does not work, I will be trying again next year with sunken hugelkultures of some sort in addition to the other techniques.

I will post updates, varieties, and weather data here as we go.

Here is the link mentioned above. https://permies.com/t/52193/urban/Building-idea-urban-sufficiency-food