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Thoughts on raised beds?

Shelley Smith
11 years ago

The heat and drought of the last couple of summers has made me re-think how I garden. I have raised beds and love them - however, I am starting to wonder if they are the best method for our hot, dry summers. Raised beds warm up faster and drain better - but do those things work against us in our climate? Would double digging the soil and planting at ground level work better? Or are raised beds, combined with drip irrigation and mulching, still the best way to go?

What do you all think?

Comments (3)

  • Okiedawn OK Zone 7
    11 years ago
    last modified: 9 years ago

    Shelley,

    I think it depends on how what sort of soil you have and on how well it drains.

    If you have a soil that is largely comprised of clay, it will hold moisture a very long time in rainy years. In areas like that, raised beds make sense because they keep your plant roots from rotting in perpetually wet soil.

    If you have soil that is sandy or sandy-silty, raised beds may dry out too quickly for you in dry or normal years.

    You have to experiment and figure out what works best for you.

    Most of my main veggie garden has a high clay content. I raise the beds above grade level because that keeps my plants from rotting in wet years like 2004, 2007, part of 2009 and 2010. However, because most of our weather is very hot and very dry, I only raise most of them 4" above grade level.

    In areas with sandier soil, I garden at grade level.

    In the worst rainy years here, which were 2004 and 2007, I still lost plants even in raised beds of well-amended clay. The soil never dried out despite being raised above grade level and plants rotted and died. That's fairly rare, though, only occurring in 2 of 14 years. Usually the raised beds drain well enough to keep the plants alive.

    In extra dry years like 2011 and 2012 (and also 2003, 2005, 2006, part of 2008, part of 2009,), I just put up to 6" of hay mulch on top of the beds with the soaker hoses or drip irrigation lines underneath the mulch. This keeps the raised beds from drying out too quickly.

    One problem with a climate like ours that has a lot of variability from year to year or sometimes from season to season or month to month, is that the techniques that work in a specific soil type in one specific type of weather may not work as well in radically different weather.

    In the areas where I have sandy soil that drains too well, I don't build raised beds and amend with lots of organic matter to help that sandy soil hold the moisture longer.

    Beds that I have double dug and amended well still drain too slowly in very wet weather because I have dense red clay. When you double dig and amend soil in a clay-rich environment, those double-dug beds, if at/below grade level, can function as tubs or swimming pools...with water pooling in the rich soil there but not soaking in well directly below the part you have double dug and enriched. So, what I have is essentially triple-dug beds with the double-dug beds at and below grade level and the 'triple-dug' part being the enriched soil raised above grade level. If you had sandy soil or sandy loam that drains well no matter what, you probably could double dig beds at/below grade level and they'd drain just fine.

    On our property the soil is highly variable. What works in one part of the yard might not work at all in another portion of the yard. I have to tailor what I do and how I do it to the part of the yard I'm in, and just because something works in the front flower bed by the front porch doesn't mean it will work 10' away. It took me a few years of trial and error to figure out which soil in which part of the yard drained too well or not well at all or whatever....and now that I'm building some new garden spaces in some new areas, I'm going through that trial and error process again to figure out what works best in each area.

    For me, it is not the typical weather that is an issue. An inch or two of rain at any given time isn't a problem. It is when we have a one-day rainfall total of 5, 7, 9 or 12+" that we have plant root issues. Or, if it rains 2 or 3" a week for several weeks straight. That happened last year and I had potatoes rot in sandy soil and onions rot in clay soil. Normally that is not an issue, but we had several big rainstorms too closely together for seed potatoes and tiny onion plants to tolerate all the moisture. If the plants had been larger and older they likely would have sucked up all that moisture and grown like mad, but with the onions and potatoes having been in the ground only a few days before the heavy rainfall began occuring, those plants could not tolerate that amount of moisture. Sometimes, no matter what you do, the weather wins.

    Dawn

  • Shelley Smith
    Original Author
    11 years ago
    last modified: 9 years ago

    Thank you so much for your response, Dawn. I always learn so much from you. I guess our climate (and soil for that matter) varies too much for any hard and fast rules.

    I do like the raised beds as they are neat and easy to manage in my very small suburban backyard. I think I'll focus on mulching, shade cloth and putting in drip irrigation this year. That and trying to time things right so crops have time to mature before it gets too hot. That's the really hard part!

  • Okiedawn OK Zone 7
    11 years ago
    last modified: 9 years ago

    Shelley,You're welcome. I think the only hard and fast rule in Oklahoma is that rule that says "There are no rules here."

    After years of working like a dog to get my clay soil to drain better, now I am beginning a new garden spot with sandy soil that won't hold moisture at all. The challenges are totally different. I am seriously considering digging up some clay from another part of the property and adding it to the really, really sandy area. Doesn't that sound crazy???? It seems so peculiar that after years of fighting the clay, now I want to put some of it into a garden spot deliberately! That is what gardening here in our highly variable weather does to you....makes you stark raving mad! lol

    Dawn