DIY Wicking Bed (Self Watering Garden Bed)
Earlier this month, I saw a great video on foodisfreeproject.org about how to build a “wicking” (or self-watering) garden bed out of recycled materials. The boys who built the bed live in the US, where materials seems to be really easy to come by. In Australia, it’s not realistic to find political signs on the side of the road - at least not ones that you are allowed to steal and cut up for your own personal use. It’s also not realistic to raid the tip for things like palettes, spare wood, tarp, PVC piping and tumbled glass. And people don’t tend to donate soil. At least not to me.
So this is MY version of the wicking bed, which actually doesn’t self water at all. But I will explain the concept in case you would like to make one that does.
BTW: VERY IMPORTANT. The pictures are there to explain the most of the process without you needing to read. You can skim read and look at the pictures and understand just fine, but if a step doesn’t have a picture then read that bit.
STEP 1: MATERIALS.
I never read the materials section. I just read the instructions and decide what I’m going to need once I’ve read the instructions and altered them to my particular circumstance. So no materials list for you, either.
Also, there is plywood in this picture. I didn’t end up using that.
STEP 2: GET A PALLET.
I got mine on gumtree.com. A lady who owns a flower arranging/garden designing/water feature installing shop gets things like pots, river stones and other stuff delivered on pallets, which the council charges her for disposal of. So she sells them for $2 each, and I bought two.
STEP 3: CHOP THEM IN HALF
I actually have a circular saw, which would have produced nice clean, straight cuts in minutes. But, neither mother bear nor I knew how to use it safely. And David said that due to the random rusty nails all over the pallet, it would be unsafe no matter what we did. So hand sawing for me.
I tried to cut them as close to “half” as possible, but because I was lazy and didn’t want to cut a slat in half, just a crossbeam, I ended up with two sides that were just over half and two that were just under. Looks silly in the end result, and I am considering chopping them down with the circular saw, so try to avoid this if you can.
STEP 4: SANDING
I learned this the hard way. WEAR SAFETY GLASSES. For a week now, I’ve had sawdust embedded under my upper eyelid, and I look like Quasimodo (apparently) with my squinty eye. I didn’t take any pics of this bit, but you can get an electric sander pretty cheap from Bunnings (or borrow one… don’t do it by hand it takes FOR.EV.ER.) The process is pretty self explanatory, and the result is nice smooth paint that looks better and goes further. Of course, if you aren’t painting or if you like the rustic look, you can skip this step. It’s for aesthetic purposes only.
STEP 5: PAINTING
This bit was really fun. I chose grey because I’m digging the white and grey theme at the moment, and I thought it would look nice with the black soil and green plants. Just ask at Bunnings for paint that has been mixed wrong - its cheap and comes in small pots too. One small pot wasn’t enough for my four sides though, so I’ve ended up with two grey sides and two brown sides which look awful, and I’ll be getting more paint to re-do the whole thing soon.
STEP 6: DRILLING
Again, I raided mummy’s toolbox and stole the power drill. By building the pallet upside down, you get “flush” alignment along the top (as in, it’s all level with no jutty bits.) This is great if your bed is going on the grass, because you can dig up the grass a little to compensate if all your sides don’t line up perfectly, and use a level to check that they’re flat. I unfortunately don’t have grass, so I am putting my planter on a weird stone tiled circle in the middle of some pebbles, which is on a weird angle. So I built my pallet right way up to get the bottom flush instead of the top, so that it didn’t wobble.
I only needed 8 screws to keep the whole thing together, but use as many as you want so that you feel confident that its going to stay together. The pallets I used were looking a little fragile, so I used a drillbit to drill pilot holes that were slightly narrower than the screws I was going to use to help the screw get into the wood without splitting it.
NB If you sit inside your square fortress made of half-pallets and drill from the inside walls out, you wont see the screwheads in the finished job.
STEP 7: WATERPROOFING
Because you want the garden bed to be self-contained (you don’t want outside weeds getting in or nutrients/water getting out), you need to waterproof it. Buy a big tarp from the Reject Shop for $4 and stick it in. Cut it so it sits nicely, and lines the sides too.
If you have pallets with spaces between the slats, use plywood painted the same colour as the pallets to cover the holes, just so that you don’t see the tarp (it looks bad).
OPTIONAL STEP 8: FOR WICKING BEDS
I didn’t do this, a) because my bed is going to be within reach of my drip reticulation system, so I’m going to hook it up to that and b) because tumbled glass/river stones/anything like that is really expensive. We actually have loads of pebbles in the yard that I could have used for free but mum said they’re “important” and I can’t take them.
Chuck about six inches of stones/glass/something in the bottom. This creates pockets of air, that will be filled with water (when you fill it). In one corner, put a fat PVC pipe vertically, sitting on top of the stones (not buried halfway in) that is tall enough to poke out the top once you’ve filled the bed with soil.
- The idea is that you put your garden hose in the pipe, which directs the water down to the glass/stones/something to fill the air pockets, without wetting the soil from the top. -
Then you get another, skinnier pipe and drill holes all the way along it in ten centimetre intervals. Put it horizontally (but on a little bit of an angle so the water can flow down) along the top of the stones, and poking out the side of the garden bed.
- The idea here is that when the air pockets in the glass/stones/something are all full with water, the water will seep into the pipe through your drilled holes and flow down the pipe and out of the bed, so that you can see that it is full and you can stop watering now. -
FINALLY you chuck something like hessian or burlap on top, which will let the water seep up into the soil, but keep the soil out of the air pockets.
THEN YOUR BED WILL BE WATERED FROM BELOW! This is way better for your plants because they take up water from the roots, which will grow down towards the water source and make for deep-rooted, hardy plants that are always watered the perfect amount.
STEP 9: FILLING
So if you filled with glass/stones/something, you’ll only have about a foot of bed to fill with soil. Lucky you.
If you didn’t (like me), you’re looking at about $150 worth of potting mix right there. RIDICULOUS. This step stumped me for a few weeks, because I’d spent a grand total of $11 on the garden bed so far ($4 for pallets, $4 for tarp and $3 for paint) and I didn’t want to spend $150 on soil. Totally defeats the “cheap” part of “cheap and easy”, which is my mantra when it comes to DIY.
So I asked almost everyone what else I could do. Some people suggested compost (clever, but just as expensive) and some people suggested green cuttings (veggie scraps) and brown cuttings (garden cuttings). Also clever, but mum just trimmed the WHOLE garden and sent the lot to the tip, so that would take too long… And my veggie scraps go to my worms, so that wasn’t practical either.
Then, finally, I asked a lady at Masters what I should do. She suggested I go to City Farmers and get a bale of compressed hay, which I could decompress and use to fill the bed most of the way, and use potting mix for just the top layer.
Then, on the way home, I saw a article on Facebook about “Lasagne Gardening” - layering compost, green and brown clippings, newspaper, and loads of other biodegradable materials to make a nutrient rich home for your plants.
PROBLEM = SOLVED.
Off to City Farmers, where I made a new friend. The hay bale cost me $18 (more than I wanted to pay…) But I still have half of it left. So if you were making two, or if you had a friend who was making one too, you’d be in the money. I totally trashed my car, there is straw everywhere.
New friend at City Farmers :)
But, as you can see by the photos below, it was a lifesaver. I bought 4 bags of potting mix from Coles (25L for $3.50) for the top layer, and used the two compost bags ($4 each from Bunnings) that I accidentally bought when I wanted to grow potatoes. I just layered it all up, and threw some worm poo (technically called “castings”) in there, along with worms to help keep everything happy for a long time. If you don’t have worms, thats cool.
First layer of hay, about ¼ of the bale. Filled 1/3 of the bed once uncompressed. (You do this with elbow grease and fingertips).
These are worm castings, with a bit of worms in there too. Maybe 10 or so, but if they are happy they will multiply.
1 x 20L bag of Compost.
More hay, and then some retic pipe. (This is connected to a hose with a timer, and has lots of little holes in it so that when the water flows it seeps out and soaks the surroundings. The hay will compress a lot when wet.
Another layer of hay.
Full with potting mix!
STEP 10: PLANTING
So, my seedlings are tiny in the huge bed, but hopefully they will grow big and strong. There’s red lettuce, cos lettuce, beans and some celery thrown in there… the lettuce was planted from seeds I got at the reject shop, but the celery was grown at no cost from leftovers of the last celery bunch I bought. I’ll write a post about how to grow veggies from off-cuts once I have a few more going.
The ones at the back are beans, which need a support to grow onto. I stole some of this stuff from near mum’s washing line, where the passionfruit vine died long ago. The wooden supports are quarters of a really long piece I bought from Bunnings for $6. Did you know you can get them to cut all the wood you buy? LIFE SAVER. Anyway it’s only up there temporarily (I used the filling of the bed to keep them supported by tucking it between the tarp and the pallet. If the beans decide they need more sun than they are getting, I’ll transplant them somewhere else, so I needed the support to be temporary.
Threading the support through the …. green stuff that I found near the washing line. Great for beans and tomatoes.
I clipped away the bits that were having to warp around the pallet. Sits nice and flat now.
And there you go. But, imagine all the sides are the same height and all the paint is one colour (grey).
Total cost : $37
$4 for 2 pallets
$4 for the tarp
$3 for the paint
$9 for the hay/straw
$14 for the potting mix
$3 for the bean support posts.
So, now that my garden bed has had a chance to start decomposing and settling in, I thought it would be a good idea to test the soil and see if I need to add anything else to the mix to keep everything healthy.
See how to use products you’ve already got in your cupboard to test your soil here. And, a mate of mine swears by Lupin Mulch for making his veggies grow, so I’m off to pick up a bag on Monday!