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Galvanized Water Trough Raised Bed Design Help

Posted by lowie Western WA (My Page) on
Mon, May 20, 13 at 19:03

Hi There,
I am looking to build five raised beds by using the galvanized water troughs as the containers. I live in the Pacific Northwest (Western Washington) and have had luck with the wooden raised beds in the past.

I'm stuck in between two designs and would love advice from people who know what they are doing to help figure this out.

The first design is a wicking one, seen here: h-gardening.pdf
The design looks great but the problem is it's obscenely expensive to get the poly mesh she references here. I can't find it for any less than $250 for the 5 beds, plus $100 for shipping. That, on top of the price of the troughs makes it a spendy endeavor. I am intrigued however by the self-watering system, only having to fill it through the feeder tube and not having to drill/seal the holes (so the galvanized metal won't rust).

Option two would be a more standard design with a drip irrigation system. Also pricey but I have a lot of the supplies and it's fairly simple. The problem I'm having, however, is with what goes in the bottom. I've read on here to not do a coarse gravel as it doesn't help with drainage. Do you recommend just the soil throughout? With our wet weather I want to make sure the soil doesn't get too compacted. I do have one of these that is two years old with raspberries which is doing fine (and is all soil), but my personal opinion is that raspberries have no problem growing in anything.

Regardless I will put them on a leveled base of pavers so they don't sit directly on the soil. I will also likely put gravel in the middle of the structure (if it will help with drainage). I will also be coating the inside with a water-based rubberized paint to protect from the zinc leaching which is a slight risk, but still better to do it right the first time.

Any recommendations are appreciated as is experiences with this.


Follow-Up Postings:

RE: Galvanized Water Trough Raised Bed Design Help

Several problems that I see. But I'll comment on only one.

Slight problem with the claim that the planting mix won't ever compact. Not possible with the suggested formula of
"one-third #2 vermiculite (asbestos free),
one-third peat moss, and one-third compost/soil (screened if

Further, the asbestos-free note is unnecessary. The contaminated stuff was from only one site which was closed years ago.

RE: Galvanized Water Trough Raised Bed Design Help

i think vermiculite compresses and breaks down.
Pumice seems better.
Or you can also mix some small gravel (no fines) right in with the soil. quarter ten gravel, or 3/8s plain, or turkey grit would work.

RE: Galvanized Water Trough Raised Bed Design Help

  • Posted by corrine1 7b Pacific Northwest (My Page) on
    Wed, May 22, 13 at 12:47

I've done some research on the idea of self watering planters, so these 3 resources may help you decide how to design your planters.

1. using prefab kits from Home Depot plus additional supplies for more productivity, less watering, & avoiding toxic metals in contaminated soils.

2. Seattle area gal who used upside pots in trough with landscape cloth over & commented on this blog page:

Salmonlady4March 28, 2013 at 7:53 PM

Hello from Seattle, Washington where every little bit of sunshine counts in gardening... All the troughs ...are sitting on plastic that is covered in gravel...on top of my old raised beds. Just put a bit of plastic netting over the drain hole and cover it with an upside down plastic pot. In fact, save all your old plastic pots, large ones are best, and turn them upside down and they will fill the bottom of the troughs. Put a piece of fabric cloth over the pots and then add your compost and dirt,straw and mushroom compost and grow away. ...and ... have not needed any other holes drilled into the bottoms because they had some of that plastic netting in front of the drain hole I pulled out. ... trailing plants hide most of the trough color and shine... wonderful ways to grow anything from herbs to potatoes and
...for those of you who want your compost near your troughs..... I just sunk two old galvanized garbage cans (with lids on top)into the ground and I put all my kitchen compost in those two cans. All I do every Spring is use a few shovelfuls from the cans in each of the troughs ...
putting one or two short pipes into the soil of the troughs and you can pour water right down into the troughs that way for the plants. ... They can easily be covered with plastic (from your dry cleaners) to warm up the soil and put in your early vegetables and get a head start on growing....

3. Val Easton on Vashon Island grows in troughs now, too, but also in wooden beds. Her Low Maintenance book discusses the troughs, but her blog shows both she uses currently.

Remember if you don't have sufficient drain holes you need an overflow to prevent rotting roots at the bottom. You may decide you don't want the expense of the troughs & that volume of soil mix.

Sometimes the most simple is best of all. I have to remind myself that all the time because there are always new ideas that might not suit my situation or budget.

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