Survive Drought with Wicking Beds

We live in a very dry climate, and all of our water comes from rain catchment. It typically rains from July through October, but the rest of the year is dry. So, we have to be extra careful with our water use, and especially for growing food, we look to increase our water efficiency as much as possible.

The wicking bed has been a revolution for us. Not only does it use less water and increase productivity, it reduces work, needing no tilling, no weeding, and generally, no maintenance. During the severe drought of 2011, we found that our wicking beds needed about 1/2 gallon per square foot per week. Compared to our normal garden beds, we saved about 5 gallons per square foot per week! That is a HUGE difference.

Our wicking beds thrived through the drought (as you can see from the photo above), where the rest of the garden was suffering, even though it was receiving more water.

The wicking bed concept is very simple. Create a reservoir of water below the soil, and water from the bottom up, rather than from the top down. This reduces evaporation losses and helps to maintain a balanced soil moisture level. Your plants will love it!

Here's how we built our wicking beds using cheap materials:
http://velacreations.com/food/plants/annuals/item/108-wicking-bed.html

We are slowly converting our entire garden to wicking beds:
http://velacreations.com/blog/item/351-more-wicking.html

I'm considering turning all my raised beds to wicking beds. I'm still pleased with my hugel beds but wicking beds in the already established area is a project I'll tackle this fall.

we are converting everything to wicking beds, as water conservation is a major issue for us. But, we also include big chunks of wood in the beds, so they are kinda hugel/wicking bed combos.

Hi Abe. Wicking beds are a great idea. Down under we use a lot of shade too over the raised beds. Sometimes, too much light can be as much of a problem as too little, so a bit of shade cloth and/or just grow the vegetables in the complete shade seems to work well here during summer. It didn't rain here for 5 months last summer which was not good, but the food forest barely needed any water during this time as I'm on rainwater and only have limited supplies. The trick with the food forest is to stress the fruit trees a bit over the years so that they forage into the sub surface to get at the ground water. I do not water the fruit trees unless there is going to be a massive heat wave and then they'll only get about half a bucket. No till also helps as the dead herbage underneath the food forest kept the soil shaded, thus reducing evaporation. How do you go with fruit trees in your area over summer? Chris

Chris McLeod wrote:Hi Abe. Wicking beds are a great idea. Down under we use a lot of shade too over the raised beds. Sometimes, too much light can be as much of a problem as too little, so a bit of shade cloth and/or just grow the vegetables in the complete shade seems to work well here during summer. It didn't rain here for 5 months last summer which was not good, but the food forest barely needed any water during this time as I'm on rainwater and only have limited supplies. The trick with the food forest is to stress the fruit trees a bit over the years so that they forage into the sub surface to get at the ground water. I do not water the fruit trees unless there is going to be a massive heat wave and then they'll only get about half a bucket. No till also helps as the dead herbage underneath the food forest kept the soil shaded, thus reducing evaporation. How do you go with fruit trees in your area over summer? Chris

Yeah, we use shade cloth as well. We typically go 8 months without rain every year.

We have some fruit trees, but are still experimenting with species that work with our unique conditions. Plums, apricots, and peaches do well here. We are experimenting with mulberry, almond, fig, pistachio, and grapes. We've lost a lot of trees, including apples, quince, cherries, and many others. It is a combination of dealing with high heat, long drought periods, and heavy clay soil.

Yikes! 8 months without rain is a challenge. Respect. Have you tried apricot trees? They seemed to thrive in the hot dry conditions here.

Also, rather than grafted fruit trees which have root systems that are probably too small for your environment, have you thought about seedling fruit trees which will produce good tap roots which can extend downwards for water during the dry periods? They grow true to type more often than not. People favour grafted trees because the tree will be smaller overall and thus more manageable, but this is not necessarily a useful trait in our environments. Truth is people are a bit scared by a 20m (60ft) lemon tree!

Chris McLeod wrote:Yikes! 8 months without rain is a challenge. Respect. Have you tried apricot trees? They seemed to thrive in the hot dry conditions here.

Also, rather than grafted fruit trees which have root systems that are probably too small for your environment, have you thought about seedling fruit trees which will produce good tap roots which can extend downwards for water during the dry periods? They grow true to type more often than not. People favour grafted trees because the tree will be smaller overall and thus more manageable, but this is not necessarily a useful trait in our environments. Truth is people are a bit scared by a 20m (60ft) lemon tree!

Yes, we have apricots, and they do well, here.

Yes, we are trying to get seedlings going, but it is a challenge with our climate, and anything that is green is basically a magnet for animals to eat it!

To be honest, I want huge trees, cause we need shade!

Robert Ray wrote: I'm considering turning all my raised beds to wicking beds.

We are on track to convert all our raised beds to wicking beds due to agressive tree root intrusion. Earlier this year we converted one 4x11 foot bed and built three 50 gallon barrel containers. I left the drip system inplace over the wicking bed, valved it off. For experientation I used the drip irrigation to get an idea of water savings. The valve had to be throttled it back to 30% of what was being delivered to the other beds, and even then it overfilled the base resevoir a bit after each irrigation set. The wicking bed super saved on the water use, also drove home how much irrigation our old system can waste even with drip. Relates to our coarse soil.

I did not use gravel to fill in the resevoir bottom, opting instead for unwashed play sand. This after filling several 1/2 gallon clear contaners with various sand/gravel choices to see which could best deliver capillary water the 4-5" vertical lift seperating the bottom of the resevoir from the bottom of the recieving soil layer. Clean gravel performed the worst: it was dry 4 inches above the "water table". Unwashed play sand performed the best.

I used copious amounts of biochar in the soil mix to improve capillary performance.

I slightly compacted my soil mix prior to planting for the same reasons. Ala the book "Plowman's Folly"

I made some mistakes:

Lesson 1: I overfilled one of my containers. Even though I immediately siphoned out the excess, the very wet soil remaining stalled the potato growth and set them back pretty hard. My solution is to plumb the overflow pipe directly into the fill-and-resevoir pipe network.

Lesson 2: the 45 mil used roofing I placed in the bed is painfully thick to work with.

But all-in-all a very rewarding experience - best performing bits of the garden were these soil wicking things. Definitely need to do more, learn more.

cross posted on aquaponicsnation.com (where my hyperlinks work: http://aquaponicsnation.com/forums/topic/9444-wicking-bedsub-irrigated-planter-resources-ideas-experiences), but I'd like to get a variety of opinions about people's experiences with Wicking Beds (or Sub-Irrigated Planters), so thought I'd post here, too:

Wicking beds might be a great choice for my site - (drylands, annual drought, already existing garden beds, etc.)

Sub-Irrigated Planters
I already have a few Ikea planters that utilize "self-watering" or sub-irrigating techniques for houseplants and I've come across DIY 5-gallon bucket designs (courtesy of Root Simple, but also found on global buckets) and nabbed three such creations off Freecycle last winter. A small stack of bakery-salvaged buckets who want to be sub-irrigated planters (SIPs) await me.

My experiences with the small scale versions of wicking beds:
the houseplants are much happier because of them. No more overwatering since the Ikea design has a small float indicator that tells when the water level is low. Very smart. A moisture meter (separate) confirms that the float is not lying - when it says there's water in the system, indeed, the soil is moist.
the 5 gallon ones are easier to misjudge, though the overflow port OVERFLOWS when there's too much water. I'm learning to ignore my urge to water from the top in our brutal summer, but I'm still not sure, though, why my plants don't look particularly pleased (an almost anemic-looking cherry tomato and a holding-steady (but not taking off) perennial African blue basil). Could be soil issues. Also, over time the plastic is degrading (unprotected) and I cut myself on a snapped edge as I was trying to move the heavy pot…
There are other "recipes" that utilize common storage totes. I have no personal experience with these.
Earthtainer - as conceived by Ray Newstead (pdf instructions)
Green tote version - by Bob Hyland
Some considerations: UV instability of plastic - unless they're underground or otherwise protected, they'll degrade. Heat detrimental to plant roots (Earthtainer design utilizes a double-wall to combat this)… and just… you know, plastic. It's not going to be here forever, what are our other options? If they only last max. 2-3 years due to UV degradation, this isn't "sustainable." Even if they last 10 years, it isn't… Also, I don't suppose it's a guarantee that nothing suspicious is leaching out of the plastic and into the reservoir/moist soil?

Ques: does burying them or coating them increase lifespan? Building a structure around them?

Here's a design using ceramic pots (though plastic is still required as a liner).

Wicking Beds

Here are some sources I came across for designing/planning such a system:
APN's own Gary Donaldson's page on Wicking Beds
How to Construct Garden Wicking Worm Beds
SIPs and Wicking Beds by Albopepper
APN (and permies) regular, velacreations, has a How To: Wicking Bed
and something similar to all of the above (the same?) from PermacultureNews


My questions for you:
What resources have you relied on to inform your successful WB/SIP design?
What has worked or not worked based on information you've come across?
Have you used a portable tote, a pond liner, or something else to make the reservoir?
Used sand, gravel (media) or perforated plastic-thingies (media-less) to create the conditions for capillary action?
Did any part of your design fail and if so, why do you think it did?
Do you import soil or create it on site? Do you have inputs from other systems on your site (ie. animal/fish waste, earthworms, beneficial bacteria)
What are elements that are critical to your system that you don't always find included in other designs?
I'll document what I end up doing on my site and will try to answer these questions when I actually have a system in place...