How to Turn Free Liquid Malt Extract Barrels Into Planters

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Do you live in an apartment or rented space and don't want to go through the trouble of planting your own hops only to move out next year? Me too. Are you a broke college student that checked the local hardware store, thrift store, and garden shop only to find that the planters are either not big enough or far too expensive for a reasonable planter? Me too.
All I found were planters a third the size and twice the price of what I could build from free plastic barrels. I used free, old 16 gallon malt barrels from the Local Home Brew Store (LHBS) and after a couple attempts I learned what not to do. I assume these barrels are relatively safe, mostly because they come with food in them and I haven't seen any evidence of deterioration over the couple of seasons I've been doing this. If you have a hook-up for larger vessels they would also work, but beware the weight.
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Figure 1: Version 3 planter in late March
THE STORY AND THOUGHT PROCESS
First I'm going to take you through what went wrong, aka the fun part. Then we'll get into how I built mine and the tools that I used; as well as some of the little tricks I learned. This article will not cover whether or not the barrels are technically big enough or really any aspects of how to grow hops, other people have covered that much better than I can. We also use these to grow perennial herbs as well, so don't limit your imagination.
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Figure 2: Version 1 Planter, currently in my recycle bin and actually looks much less twisted and slumped without dirt.
Versions 1 and 2 were built within a couple days of each other so they have a couple of the same problems, but for now version 2 is still in service. For version 1 the idea was to cut the top of the barrel off and use it as the bottom. By bolting it to the bottom the planter wouldn't roll away. The first problem was that the plastic wasn't stiff enough, so the upper portion twisting and distorting was quickly realized. This was modified in the second planter (which can be seen in figure 3), but at that time the first planter hadn't been filled so I didn't realize the bottom wouldn't be strong enough either. It didn't help that in the interest of being cheap I used a few rocks in the bottom and some double dug local soil; which it turns out, is just clay. The rocks were used partly as filler and partly because I thought it would help drainage, but it turns out they just added a lot of weight.
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Figure 3: Version 2 planter, notice how it has slumped forward due to the poor base design.
You can see from the picture that version 2 was modified in an attempt to keep the upper portion from twisting, which it did, to an extent. The one obvious additional advantage is the handles, but it made the now 3 part base even less stable. The plastic bases tend to continually get worse over the first couple months.
Version 3 turned out to be a nice, easy, and extremely cheap planter. The only thing that I would change is to use pressure treated wood for the feet. An 8' pressure treated 2x4 is only a few dollars and can be used to make 4-6 planters. Leaving the ends intact gave much need structural support to the body and since I planted the rhizomes in the middle it hasn't effected growth. The ends also serve as nice handles for 2 people and are functional if you're working alone. Using more traditional potting soil made the whole system lighter and since I always put drain holes in the bottom I'm not too worried about drowning the plants.
MATERIALS AND TOOLS
- Plastic barrels, free at my LHBS, but I have seen places that try to charge a few bucks. It's worth noting that some people use these as extra-large primaries, so there is a small demand.
- Typical wood screws, 2-3" screws should work fine
- A 2x4, preferably pressure treated
- A saw to cut the 2x4, circular, miter, or similar
- A drill and bits, used to screw in wood screws and add drain holes
- A saw, grinder, or torch to cut barrel
- A tool to smooth the cut edges (optional)
- A flexible straight edge to mark the barrel
- Marking pen - sharpie, paint marker, grease pen, etc.
- Soil and plants/rhizomes, typical potting soil tends to be lighter which is nice for moving reasons.
BASIC CONSTRUCTION WITH ADDITIONAL TOOL IDEAS
I used a straight edge and paint marker to mark off the area I wanted to cut out. I'm sure you can do this a lot of ways depending on what you have available. Then I cut the plastic using a 4" grinder with a cutoff wheel. Which worked reasonably well, but there was a fair amount of molten plastic; most of which got caught in the guard. You'll want to have safety glasses and newer cut off wheels. I managed about 2 planters/wheel. I also think a jig saw would work well, but you would want a friend to hold the barrel steady. Other ideas include a circular saw with the right blade and some skill, a zip saw, reciprocating saw (might be too violent and end up looking poor), and a plasma torch (just because I want to see someone try). Since I used a cut off wheel and melted some of the plastic the edge wasn't great, so I put on the flap disk and cleaned it up bit. Clean up could also be done with a sharp knife or various deburring tools.
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Figure 4: End view of Version 3 planter
The next step was cutting the 2x4 into the right sized wedges. I assume the reader can figure out how to size the wedges to their barrel without much trouble and/or a little trial and error (see figure 4). Then you need to put a couple of screws through the plastic into each 2x4 wedge. Depending on the wood, screws, screw placement, ect you may want to predrill the 2x4; I did. As for lining up the 2x4 through plastic... I never came up with a good method, but I think one of the commenters did. After the barrel is off the ground go ahead a drill a few drain holes. I drilled 5 holes 1/2" diameter evenly spaced at the lowest point. The planter drains well when over watered and I haven't noticed any clogging or excess moisture problems. Also, I don't think the rocks were ever necessary for drainage and I didn't notice any benefit to the rhizome roots that I transplanted. Beyond that it's soil, plants, and a horticulturist's advice.
A COUPLE OF FINAL THOUGHTS
The first year I did this, I put my hops in our unheated and uninsulated garage over the winter; which I think was a mistake. I was trying to protect them from an overly deep freeze (Colorado), but what I unintentionally did was keep them from getting any moisture. I'm quite sure they got the necessary freeze, but didn't seem to come out of the winter as well as this year, when I simply left them outside (At least -9 F for 24 hours).
These are going to need a little more attention than hops in a typical ground planting. The barrel seems to be a good size for the root, at least the first couple years, but they need more frequent watering. My girlfriend all but killed mine when she sparsely watered them while I was out of town for a week in July. Also it's worth looking into what they need for additional nutrients, so far I'm periodically adding in a little blood meal for nitrogen, but I'm just guessing.
Thanks for reading, happy brewing and good luck with a hop garden!
Casey "Dick" Ritz is an avid homebrewer, originally from the state that drinks more beer than any other, North Dakota. In 2008 he was a humble college student just trying to save a few bucks and that's where all the brewing began.
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Cool tip on the barrels, I'd love to get my hands on some of those for all sorts of purposes. Emailing my LHBSes now...
 
My LHBS's charge for them. Anywhere between $10 and $20. I picked one up a few years ago that I use for a primary fermenter.
 
i usually cut them around the middle horizontal rather then vertical (if the barrel is standing up) but i may have to give this a try.
nice job
 
@NateLTB I checked with one of mine, and the guy was like "Huh? Oh yeah, check by the dumpster on Tuesdays." I'm all over this.
 
Thanks for the kind words!
It's surprising to see the wildly different values people place on old plastic barrels. Not sure about the other brewers looking for these, but I live in a big college town. I suspect we have a larger proportion of extract brewers and not as many of us doing 10+ gallon batches. Maybe that's part of the reason for the different values.
 
I'm in NateLTB's boat... just picked one up for $10. Waiting for a nice warm day to christen it with 10 gallons of stout.
 
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