I have been playing around with and researching different wicking bed designs/ideas for the last 5 or so years in Townsville and absolutely love them for a few simple reasons. They work, they are cheap, they save water and things just grow much quicker in them. Here's what you would need for a simple pop-up wicking bed:
- The Frame - I have used a pop-up system that I have co-designed with a local cabinet maker, you can use old pallets, wooden sleepers, clay soil, an old pool or basically anything you can get your hands on/repurpose.
- The Liner - $8.50
- The Overflow - $2.50
- Storage Media - Free or $25 for 1/4 m3
- Growing Media - Free or $25 for 1/4 m3 of mill mud
- PVC pipe to connect to Storage Media - $3
- Media Separation - Free as I used an old bed sheet
- Beneficial Microbes - Free and great fun to grow
- Some locally sourced seeds or seedlings
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Step 1: Assemble Your Frame
Your frames are only limited by your imagination with wicking systems with a few considerations:
- soil wicking rarely wicks above 300mm
- placement of your bed is key, understand what you want to grow before placement
- look for free water sources to save you time - I have systems that require no potable water as my roof and air conditioners provide plenty of water for them
- use your fence to keep the garden cooler when in hot climates
- you will need to reach whatever you grow so size is important - these are 1m x 1m x 0.5m high
These particular frames are a design that a local cabinet maker and I have come up with. The pictures show the basic design and we have gone for something that assembles in only a few minutes, is pre-cut and can fit in the back of the car. I have other beds using old pallets, they work just as well and cost nothing.
Step 2: Line Your Frame
The most important element of your system is the liner, you want to ensure that it is not damaged in any way and will hold water without loosing any. I have purchased a 5m x 4m length of black builders plastic (100 microns thick) and doubled it over to be sure - its cheap and effective. I have also used seamed pallet bags (second picture with clear bag) however they are a little trickier to get your hands on.
I like to lay the liner inside the frame, fold it into position and tape it into place ready for my storage media.
Step 3: Add Your Water Storage Media
Your storage area should be approximately 20-30 cm deep and the purpose of this layer is to hold the maximum amount of water to save you time in watering. I have done quite a bit of research here and the key is to use a media that is rounded and consistent in size. I have used river rock in these 2 beds as it was free from the side of my house. Sand will also work well however make sure it is screened and washed to ensure the maximum water can be held. Rock or sand grain size has very little influence on the water holding ability of this layer with most storage media layers holding between 40-50% water. For example, this later is 1m x 1m x 0.25m so would hold 250L of water and approximately 100-125L of water with this river rock in it (plenty for a few weeks without water).
Step 4: Add Your Sheet and Pvc Pipe
It is important that you separate your storage media from your growing media (soil) so that your storage media does not get clogged with soil. I used my wife's old (I strongly advise to seek consent prior to using good sheets - I take no responsibility for any consequences here..) purple bed sheet in this system - you could also use old t-shirts, pillow cases, geofabric or basically anything that can stop the soil from getting into your storage zone.
You will also need a way for you to apply water directly to the storage media zone - I use a simple pvc pipe going directly into the bottom layer (pic above). Some people use slotted ag pipe - its a little more expensive and wont change your water holding capacity much so I would suggest saving your $ and just using pvc offcuts.
Step 5: Set Up Your Water Bypass/overflow
Before adding your growing media, you will need to set up your water bypass (pictured above - the black pipe). This is a simple sealed overflow that is part of the kit (<$3 at hardware store) however you could use just about anything as long as it allows water to exit your system once it is too full. Make sure the overflow is below your growing media - if it is in the soil it will have trouble draining. I typically surround it with some rock.
Time tip - you can join your wicking beds to make them a series if you direct your water bypass/overflow directly into your next pop-up wicking bed (see picture above - white piece of pvc joins the beds so that I have only one top up point for as many beds as I like).
Step 6: Add Your Growing Media and Get It Ready for Action!
After adding your separation layer, watering point and overflow, its time to add the good stuff. If you are going to spend any money, this is the area to not be cheap as it is essentially what will drive the success of your project - the foundations for plant grown is soil and you need three key element:
1. soil structure
2. soil chemistry
3. soil biology (don't forget the bugs/microbes!)
I have used mill mud from a local landscape supplier, its is slightly more alkaline than topsoil however it is just brilliant for most crops. You will see that I have inoculated (fancy word for me adding microbes) this growing media - it will take your system to the next level and I have added an extra step on inoculation next (optional).
Your soil will settle over time so don't be afraid to fill your bed right to the top and I have used a 300mm growing media depth - you can go more if you like and it all depends on what you would like to grow.
Step 7: Making and Adding Your Bugs!
Brewing your own beneficial microbes at home is cheap, easy and fun. I use a product called 'liquid bokashi' and if you live in Townsville, you can pick some up from Otto's on Bayswater Rd (picture above). Simply grab yourself a sealed bucket and grow your microbes by adding vegetable scraps and a few sprays of liquid bokashi each time you add produce. After a few weeks you will end up with a bucket of dynamite for you veggies/herbs. I like to add some boiled water (tap water may limit growth of your microbes) and a handful of sugar (to feed the microbes) a few days before adding. The cool thing about microbes is that they can stop your bed from going anoxic in the lower layers, bring carbon into your soil and also have a byproduct of water (whohoo). Just mix them into your soil every few weeks or when you rotate crops.
Step 8: Chose Your Plants Carefully and Have Fun!
Now is time to involve the family and plant away. I have very little trouble directly sowing seeds into the beds and would recommend watering from above the first time you plant and then the system will take care of it from there.
Enjoy your wicking journey and remember that building the bed is the easy bit - take you time to plan and take care of your produce and share your successes with your friends/neighbours!
Tip - why not try and grow your food without any potable water? Above is a bucket under my downpipe, more than 10L of water comes off my roof most winter nights (condensation) and that's more than enough for a wicking bed. You could also bucket water from the shower, use your air conditioner water (more than enough for a wicking bed) or link to your rainwater tank if you have one...