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Daron Williams
pollinator
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Location: Olympia, WA - Zone 8a/b
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I have been thinking about building a garden using all hugelkultur beds with the aim of not having to water the beds at all by taking advantage of the ability of the wood within the beds to absorb water. However, a couple years ago in my area we had a very hot, dry and unusual summer - unusual now but I have read that it might be the norm for our area in a 20 or so years. Because of this I want to be able to have a backup water system for my hugelkultur beds. Now I could just use drip systems or overhead systems but both options don't really take advantage of the nature of hugelkultur beds. I have been thinking about using a system that I used in my old wicking beds - these beds had a pvc pipe system that allowed me to add water directly to the bottom of the beds. This worked very well and I rarely had to water these beds and the plants remained very happy. I was thinking about doing something similar with a hugelkultur bed - while building the bed I would put the pipe (with holes drilled in the bottom and weed fabric wrapped around it) in the bottom down the middle. One end of the pipe would be capped and the other would curve up 90 degrees so I could fill the pipe with water from a hose as needed. This would allow me to apply water directly to the core of the hugelkultur bed and take advantage of the ability of the woody material to absorb water. The wicking beds had a gravel reservoir to hold water and the hugelkultur beds would have a woody reservoir (later very rich soil). My thoughts is that I would only use this system if absolutely needed due to an extreme drought and most years it would all remain capped.

So, do you all think that this system would work for emergency watering? Would the water leaving the pipe cause erosion from within the bed? How long do you all think the pipe system would hold up? Could it be installed now and be good for decades? Do you all think this would allow for "recharging" of the hugelkultur bed during extreme droughts? Any thoughts on what diameter of pipe would be needed?

Overall, I'm convinced that hugelkultur beds can eliminate watering once well established and if large enough in my area but I also want to be prepared for those super hot and dry years that are going to be more common in the future. My view is that with climate change we need to have backup systems to help deal with possible extremes and this system was one that I was thinking about setting up.

Final note - I'm also planning on using other permaculture techniques such as swales, mulching/chop-n-drop, polycultures, developing landraces, etc. to help with my goal of not needing to water. But I also want to have an emergency system in place if all else fails.

Thanks all!
 
s. ayalp
Posts: 23
Location: istanbul - turkey
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dog greening the desert hugelkultur
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Well I tried it. It doesn't work as expected. Let me try to explain what I have learned by trial and error. On personal level: Istanbul has a weird climate. Yes it has all four seasons, but it also has a 11 year cycle. So like in every 11 years we are hit by drought for2-3 years which elders used to call "summer years". We also have "winter years" like the previous 2 years when we had up to 50% more precipitation as snow. So I have to take "summer years" into consideration.
Hugelkultur is kinda like dam reservoir and farmland combined. When the drought hits, prime goal is not fill the dam but to get some production going. Water is scarce, so you want to spend all the water to the plants. If you can fill the dam meanwhile, that is great. Also wicking beds are usually made out of plastic, so there is no leakage at the bottom. Hugelkultur on the other hand is open at the bottom, and mainly an above ground structure. I don't know how fast wood can absorb water, but it should be pretty slow. So if one wants to water a hugelbed, it should be really slow (or submerge the whole bed => last line), like drop by drop. Drip irrigation mimics it. It creates a moist blanket over the wood core while watering the plants. Also if the situation is worse enough to water a hugelbed, it means most of the soil has already dried out. There wont be chain of soil particles for the wicking action and to make things worse many types of soil become hydrophobic. They will just let the water pass. A moist blanket keeps the wicking chain intact.
I see you are in WA, so I would recommend drip irritation. You don't have to wait drought to use it. Also you don't have to put the pipes all over the bed, only at the top Ft or 2 is enough to water the whole bed.
One more thing to add to this topic for permies people closer to equator
Underground hugelbeds / buried wood beds are the antidote for sudden 1-2 year droughts if not more. burried wood beds
 
R Scott
Posts: 3349
Location: Kansas Zone 6a
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I would put it near the top, like on top of the wood after the first dirt is dumped and filling the spaces, but before the final dirt.

There are drip lines made to be buried, sub surface irrigation.
 
Daron Williams
pollinator
Posts: 210
Location: Olympia, WA - Zone 8a/b
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Thank you for the response and those are good points. I have a couple questions for you.

Likely a drought that would stress a hugel system would happen after the plants roots were fully established (mid-summer) which I thought would mean less need for the water to be pulled up through the soil by the interaction of the water and soil particles since the roots could access the water directly. Do you think this would work?

Also, I was assuming that the wood would have had time to decompose at least a fair bit before I would need to use this system. But even if it had not I would think the soil could absorb a fair bit of the water on its own. But if the wood had decomposed a fair bit I would think that it would be able to absorb a lot of water especially if I set it up the pipe to slowly release the water. I should note the soil I have here is very heavy in clay and would drain very slowly which would keep the water around the beds longer. My thought was to give a heavy subsurface watering (keep the water going for several hours) to help recharge the system - this would be done only once or twice through the drought. Does this change your thoughts at all?

I'm not a big fan of drip watering systems or any surface based watering systems as a response to drought. The main reason is that if you do dryland farming your plant roots will be trained to go deep but if you then apply water to the surface the deep roots are not being reached and the plants would instead spend energy on the surface roots which could undo the deep root training. This seems like it would make the plants less resilient not more over the course of the drought. Am I not understanding this process?

I'm also hesitant to use drip systems for the situation I outlined for a couple other reasons. If I had not already installed the drip system it would be very difficult to place it around a dense and established polyculture. If I did install the drip system at the start then most years it would just sit there unused and the extra work would be waisted each year. If I left it in place then it could degrade while not being used - my experience with drip systems is that they are not made out of the strongest material. The other reason is that a drip system would need to be used regularly over the duration of the drought since it would just be applying water to the surface. This seems to me that it would not be taking advantage of the nature of a hugel bed. What are your thoughts?

I should add that I did use the system I outlined in a traditional non-hugel raised bed in a much hotter and drier climate and it greatly reduced our watering needs. The raised beds were 4ft high and the pipes were about 3 feet below the surface. Now since the beds were not hugel beds we had to use the system during normal years. But it did work great for watering the plants and we only needed to water every couple weeks in the middle of the summer. Why would the system work in this setup but not in a hugel bed?

Also, all my hugel beds are partially buried with about half below the surface and half above.

Thanks again for your response and I look forward to yours and others responses to my questions. 
 
Daron Williams
pollinator
Posts: 210
Location: Olympia, WA - Zone 8a/b
28
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R Scott wrote:I would put it near the top, like on top of the wood after the first dirt is dumped and filling the spaces, but before the final dirt.

There are drip lines made to be buried, sub surface irrigation.


Thanks for the response - how long can those buried drip systems last before needing to be replaced? I was hoping to setup a system that could last for decades though I'm not sure if that would be possible.
 
R Scott
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Location: Kansas Zone 6a
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There are different grades, but the shortest lifespan claim I have seen is ten years.
 
s. ayalp
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Vegetable roots were not sufficient to pull water 1-2 Ft in my case. The best explanations I came up is that: they don't have deep roots (more than 2 Ft) and air gaps form as hugel tills itself by time. Those zones get dry enough to air prune roots. So they never make it through actually.
I also have heavy clay soil. Almost pure red clay. Drainage was a big issue. I built a 4 Ft high hugelbed and it was over 1.5 year old when it got tested. Dried out pretty quickly. I thought that I did everything right while I was building it so I tried to come up with a new design. (Later on I figured out why it failed, I didn't alter wood and soil layers. It had only 4 layers and there were gaps in the core. I mean big ones. Dismantled and built a proper hugelbed with a drip irrigation on top, works like charm). In 2013 I built that new idea (please see the picture). It had a reservoir at the bottom. I filled that zone with wood and soil. I put a pipe to directly fill it. The above ground part was 2 Ft high, with a lot of soil and wood to aid wicking. Since I am living on a hillside, I needed a flat are to work on. So it is a table top design. It did work, but more like 30-40% efficiency. Then it started to settle, gaps formed again with some help by critters. I waited the system to respond, it didn't for 2 months (creating dry air gaps). So I filled the reservoir multiple times, but it also didn't help at all. Finally I installed a drip irrigation system all over the top to rescue what was left. To my surprise, when the wet blanket was formed, hugel started to work again. But this time I was not watering from the bottom. This winter I built a hugelbed with a reservoir and a pipe to fill it (5ft above ground 3 Ft below). We will see how it will respond. To create an artificial drought I will cover it with plastic in April-may and winter when it matures. But meanwhile, with the idea of "what if plants were able to reach the reservoir themselves" I built a similar design with only half a Ft above ground. I filled it twice while I was slowly building it, but never later on. It is working with no irrigation for the last 2 years. So to my experience, when drought hits hugelbed with a drip irrigation on top gets a big candy, table top hugel with reservoir gets "yeah that was ... fine..", and buried wood beds get a a round of applause.
So why am I building a hugelbed with a reservoir? Curiosity killed the cat, but satisfaction brought it back (:
What I understand from drought is a bit different I think. If there is a sudden drop of 20 or more % of precipitation that is drought (PNP). When it hits I don't know how long it will last, I don't know how hard it will hit. If plants are trained beforehand, I will drip irrigate  far in the root zone to keep roots healthy. If not, right under the plant. 20% can be dealt with good practice, 40% or more will definitely kill no matter what. All I ask for the production is to go on. Personally I would not try to modify their behavior when hit.
I am using the same drip-pipes on the same bed for the last 4 years with no issues.
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cross section of the second trial
 
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