Gardening Question of the Week
Would Sunken Garden Beds Be an Advantage in Dry Climates?
Thursday February 21, 2008
Last week I wrote about raised bed gardening and I got an interesting response from Sara.: “Your recent article about raised beds, called to mind a question I've been pondering. In hot, dry climates such as So. California, what about sunken beds? Would they hold water longer so the plants don't dry out? I know in some areas such as AZ, the grass areas are somewhat sunken, then flooded once a week with water. They find that it saves on water usage while keeping the grass moist for about a week. I am referring to vegetable beds, here. What would be the advantages/disadvantages?”
I haven’t really been able to find any information on sunken gardens, other than for aesthetic purposes. Have any of you experimented with this idea or do you know of any resources we could direct Sara to?
Photo: © Marie Iannotti (2008) licensed to About.com, Inc.
Comments
Sarah,
I have found that planting my vegtables between raised rows in the garden in draught prone areas has improved production and made watering directly to the plants by flooding the improvised ditch a great advantage.The soil tends to hold the moisture better if the rows run north to south because they receive overhead sun only part of the day while the plants remain exposed to the rays.
Bill
If your walkways are recest and mulched thay water well.
Re: Coffee grounds. I used coffee grounds from Starbucks “Grounds for the Garden” program for several years. My orange clay soil has turned into a rich brown loam. Definately an improvement. Don’t mix the grounds immediately with the soil, it will take out the nitrogen in order to decompose it amd your plants will turn yellow. Instead, use it as a mulch and it will eventually find its way underground by the action of earthworms. Don’t worry about mixing small amounts into the soil when digging in new plants.
1.
Sarah,
I have found that planting my vegtables between raised rows in the garden in draught prone areas has improved production and made watering directly to the plants by flooding the improvised ditch a great advantage.The soil tends to hold the moisture better if the rows run north to south because they receive overhead sun only part of the day while the plants remain exposed to the rays.
Bill
Comment by Bill Raynor — February 21, 2008 @ 1:42 pm
2.
If your walkways are recest and mulched thay water well.
Comment by Rock — February 21, 2008 @ 1:47 pm
3.
Re: Coffee grounds. I used coffee grounds from Starbucks “Grounds for the Garden” program for several years. My orange clay soil has turned into a rich brown loam. Definately an improvement. Don’t mix the grounds immediately with the soil, it will take out the nitrogen in order to decompose it amd your plants will turn yellow. Instead, use it as a mulch and it will eventually find its way underground by the action of earthworms. Don’t worry about mixing small amounts into the soil when digging in new plants.
Comment by Christa — February 21, 2008 @ 6:09 pm
I visited a below grade water garden in Paradise Valley AZ. It was approx 8×8′ in back of a brick BBq..entirely of brick, with steps down from the patio. It had space for 2 chairs, a pond & trailing plants & ferns. since it only received Sun about 2 1/2 hours per day it was cool & pleasant.
Here in sunny Florida I have used raised beds primarily because of the poor soil (sand). But I found it really helps during the dry seasons.
Kate
Garden Tips 123
PLEASE try a Rain Garden! It is a sunken garden with a few extra additions. I am in the process of explaining how to do it on my blog found at
It’s a perfect solution for you!
I agree, rain gardens are wonderful solutions, in the right spots. Unfortunately, this is not an area where water normal collects or runs off and I don’t want to encourage it to. It became a problem because it was the only tilled area in an otherwise compacted lawn site. Prior to that, the water flowed far from my house, where it is welcome.
Hi Sarah,I have read some good somments,let me add:I live in southern California,south of San Diego. Here we have a layer of clay about 18 inches down[depending on how the property was graded when homes built].So,for me sunken is not an option..however,when you build a raised bed,if you double dig,then use 2″x10ft[width]xXft.[length]planks of wood,burying to a depth of at least 3-4 inches,water has no place else to go but down..especially if you keep the top of the soil areated,+[lightly mulched on top is a bonus].you can seal the side piece to the length with solicone[also used for aquariums].sunken gardens sounds great,yet a better concept to use where they have rock quarries for swimmimg![smile]
if lack of available earth to fill a raised bed and/or water retention is the issue;1.incorportate more amendments to the soil and 2.our clay/sand soil forms a hard crust when the sun evaporates the moisture on a daily basis..almost cement-like,so cultivate the area around
the plantings,encouraging the water to sink.Best of luck. Happy gardening,Raychael
It’s a great question. Sunken beds work wonderfully for hot, arid regions all over the world. Why?
–they create a microclimate that is naturally a couple degees cooler (just like basements are cooler than the rest of the house)
–they allow for the collection of rainwater
–they protect the above ground parts of plants from hot winds and the root zone from burning temps
–in many hot, arid climates, the soil is alkaline with high salinity. When salty soil is watered, the salts tend to migrate to the highest point – with raised beds, that’s the root zone – which just adds to the problem of growing plants in a hot, arid climate.
–sunken beds also attract more plant litter than raised beds thus naturally allowing for soils to build themselves up over time – something most deserts desparately need.
I’ve done sunken in vegetale gardens in Phoenix for a few years now and am really happy with the results. Even though my garden keeps getting bigger, my water bill doesn’t grow that much because I’m building soil and retaining water in my sunken beds. Oh – and no – my beds have never flooded out even in the heaviest rains because I’ve built good spongy soil so it just keeps on seeping in. Add a good layer of mulch and you conserve a lot of water and make a microclimate plants LOVE.
Check out nativeseeds/SEARCH. They have some pics of sunken beds at their seed farm in Tucson. nativeseeds.org