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hendi_alex
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Before and After

Over 20 years ago, after fighting wire grass (coastal bermuda) and poor sand for many years, I ran one of my first major gardening experiments, pouring a concrete skirt around a series of in ground beds. This area is adjacent to an old concrete carport floor. The material in the bed area was amended with copious amounts of organic material, both commercial as well as home made compost. The approach turned out to be a great solution to the grass problem, but not so much for the poor, sandy soil. After what seems like hundreds of cubic feet of amendments, the soil is still essentially dry and sandy.

A couple years after forming the in ground beds, a series of three large planter boxes were placed on the concrete pad. Since that time, those boxes, sitting directly on the concrete have been by far my most productive areas, nothing else even comes close.

Now the oak tree roots from 75-100 feet away have found the in ground beds, plus have even found their way into the above concrete beds, moving in through small cracks in the 30 year old slab.

In accepting this reality, and as part of a transition toward developing an 'eldy' friendly gardening area, I'm resurfacing and slightly expanding the entire area to make a gardening patio. This is not very consistent with my 'organic' permaculture leanings, but represents a compromise that will give a much better gardening experience in future years. Actually the foot print is only somewhat larger with the new concrete mostly sitting over the existing slab, so very little additional degradation in that regard. This 27 foot by 35 foot space only represents a tiny fraction of our 130 acre site which is managed almost exclusively via low impact, eco friendly ways. Perhaps a bit of a rationalization, but probably is also a balanced way to look at the decision.

Here is a before photo.
Image

Here is a photo of the new slab. New beds to follow. Not sure if I'll replace the arbor or not.
Image

Progress will be posted as the project moves toward completion.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.
Alex

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lakngulf
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Re: Before and After

Will be interesting to watch the progress on this. Quite a change, and a thoughtful approach to develop the best option. No doubt tree roots will find fertile soil and rob from your veggies. I battle various weeds and grasses every year. I just hauled in a new load of matured manure from the farm. As I unloaded I imagined all the seeds that would give me fits this year.
Nutin as good as a kitchen sink mater sammich

imafan26
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Location: hawaii, zone 12a 587 ft elev.

Re: Before and After

Blank slate, I think of it as an opportunity to perhaps make it better.
Happy gardening in Hawaii. Gardens are where people grow.

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hendi_alex
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Re: Before and After

Getting beds in place. Five of 12-16 beds completed. Size is 42 inches by 78 inches.

Image
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.
Alex

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ElizabethB
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Re: Before and After

A very thoughtful and beautiful gardening concept. :cool:

How do you address lime leaching into the soil from freshly poured concrete? What about drainage? More information please.

When I consider all of the years spent battling tree roots the idea of a series of boxes on a slab is very appealing.

Other questions - how thick is the slab and how deep are the footings? What about reflected heat?

Please share more.
Elizabeth - or Your Majesty

Living and growing in Lafayette, La.

When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant. ~Author Unknown

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hendi_alex
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Re: Before and After

This new pad was poured over an old garage pad. Planting boxes over the old pad have been used for years with great success. Actually the rain here is slightly acidic, so the concrete could well act as a permanent buffer. At any rate, plants have always grown well with good color.

The boxes are set flush on the concrete but water simply seeps from under the frames. Very little water stands as the slab has a pretty good slope to it. The soil does not tend to stay overly wet.

I got this pad professionally poured. $2500 for approximately 27 feet by 35 feet by 4 inches deep. There is room for up to 16 boxes of the size being used. No footings are needed for a concrete pad, footing are to support weight of a structure such as a house. The slab does need to have joints sawed to prevent cracking. Mine are about every 8 or 9 feet.

Reflection has never been a problem. As you see in photo of my original pad, much of the concrete was left bare, perhaps the plants liked the reflected light, getting a little extra photosynthesis. During the hottest part of summer, I will likely use shade cloth in some way to filter or block the hot afternoon sunlight.

You may want to look at my pond liner experiment that is a much less expensive version of the barrier concept. The two liners each 10 feet by 20 feet cost under $400 together. They are very heavy 45 mil sun resistant material. The post is under '2015 experiments' updated today with new photos.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.
Alex

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lakngulf
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Re: Before and After

I see a retractable green house in this pads future

How tall are your boxes?
Nutin as good as a kitchen sink mater sammich

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hendi_alex
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Re: Before and After

Used 2 in x 10 in treated lumber, so about 9.25 inches deep. My earliest version of boxes were made with two by sixes and they worked just fine as well. If more depth is ever needed, I'll just go up another board and will flash the seams. The greenhouse is about 100 feet from the bed. It is 10 feet by 28 feet. I may fashion some cold frames that fit just inside a bed area. Those work really nice to keep lettuce and arugula growing during the colder part of winter.
Eclectic gardening style, drawing from 45 years of interest and experience. Mostly plant in raised beds and containers primarily using intensive gardening techniques.
Alex

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