how to make wicking garden beds

how to make wicking garden beds


A wicking mattress is a self-watering raised backyard mattress, and though the design is a comparatively new innovation that’s catching the eye of many produce gardeners worldwide, it’s basically nothing greater than a big scale model of a self-watering pot. Self watering pots have been round for many years, and are based mostly o the precept of sub-irrigation, the place the water provide sits under the pot that’s depraved upward into the soil within the container above.

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This text supplies detailed step-by-step directions on easy methods to construct a wicking mattress, however earlier than we begin constructing something it is very important perceive how wicking beds work, so we all know precisely what we’re constructing and easy methods to modify the design to our wants if we have to.

Additionally, when contemplating wicking beds, it’s actually necessary to find out whether or not this method of gardening is appropriate for our wants as gardeners. By understanding the professionals and cons of wicking mattress gardening, we will make the appropriate selection and get the very best outcomes gardening with this wicking beds.

The Benefits and Disadvantages of Rising in Wicking Beds

Wicking beds are nice for conditions the place watering is rare, corresponding to neighborhood gardens and college gardens the place no one is current over vacation intervals to water the backyard beds. The water reservoir in a wicking mattress can carry sufficient water to maintain the crops alive for as much as a number of weeks relying on local weather, season and site. They’re additionally helpful for gardening below and round timber with invasive roots that extract each final little bit of moisture from the soil, corresponding to Australian eucalyptus timber.

Rising crops in wicking mattress methods is a helpful approach that will increase the vary of prospects of what you may develop the place, and wicking beds have their place and goal in a gardeners repertoire, however additionally they have their limitations similar to any synthetic gardening system. What are these limitations it’s possible you’ll be asking?

Most crops require a wet-dry cycle to develop, however wicking beds create an setting with continually moist soil which is unsuitable for a lot of crops. Since water is retained in a wicking mattress, this results in a construct up of fertiliser and the evaporation of water from the soil mixed with the upward wicking creates a state of affairs the place the focus of salts can construct as much as harmful ranges within the soil that may burn the roots of the crops. Additionally, the upward transferring water carries the surplus salts upwards, so the salts accumulate on the higher soil ranges the place shallow rooted seedlings are planted.

One other problem is that the bottom soil ranges in wicking beds are at all times moist, whereas the higher ranges will be pretty dry, as a result of the soil can solely wick moisture up so excessive via the forces of capillary motion, adhesion and cohesion in opposition to the forces of gravity. As a consequence, the moisture out there to a crops is determined by the peak of the backyard mattress and the depth of the plant roots. Deep rooted crops which dislike ‘moist toes’ (continually waterlogged soil) shall be very sad in a wicking mattress, and can normally fail as a consequence of root rot. It is usually necessary to think about {that a} wicking mattress in in actual fact a container backyard, and all containers of soil or potting combine/medium have what’s termed a ‘perched water desk’, a layer of water-saturated soil on the backside of the container that by no means drains away. If this layer is consistently wicking up extra water, it could possibly by no means dry as a consequence of evaporation or uptake by plant roots, and turns into a soggy, anaerobic (with out air/oxygen) sludge which will promote root ailments.

The primary disadvantage for most individuals is price. Giant correctly constructed wicking beds are costly to construct. In my thoughts gardening ought to be easy, low cost and sustainable. My primary rule of gardening building is as follows. Solely use a raised backyard mattress when rising within the floor isn’t attainable. If utilizing a raised mattress isn’t attainable, solely then use a wicking mattress. The fee and building effort concerned going from gardening within the floor to raised beds to wicking beds jumps astronomically with every step.

Wicking beds aren’t a common gardening resolution, and if we preserve this in thoughts and use them the place they carry out finest, we will finest make use of the advantages whereas avoiding the disadvantages.

Wicking beds for my part, very like hydroponic methods, are finest suited to rising annual greens, that are so brief lived they don’t reside lengthy sufficient to develop long run issues as a result of soil circumstances, and require massive quantities of vitamins in a brief interval. Since wicking beds retain fertiliser all too readily, much less fertiliser can be utilized for annual vegie rising. As such, wicking beds make nice intensive vegie beds and kitchen backyard beds.

Now that we perceive the advantages and limitations of a wicking mattress system, let’s take a look at how they work..

Wicking Mattress Design Idea

A wicking mattress is kind of a easy design as proven within the diagram under

The dimensions of the wicking mattress is basically private desire, it may be range from a small tub which sits on a desk or stand, right through to a full backyard mattress sized wicking mattress system.

Widespread wicking mattress sizes are decided by the size of commercially out there raised beds or building supplies.

  • For very massive wicking beds, railway sleepers are sometimes used, and the size and environment friendly use of supplies dictate the scale. A railway sleeper is 2.4m (8’) lengthy so a well-liked measurement is 2.4m (8’) x 1.2m (4’) as this makes use of three sleepers to assemble a single degree. A typical top when utilizing such supplies is 60cm (2’) excessive, as every sleeper is 20cm (5”) excessive, and if they’re stacked three excessive, the full top is 3 x 20cm = 60cm (3 x 8” = 24” = 2’). Such a design makes use of 9 full-length railway sleepers. One other design choice to save lots of 1/3 of the supplies is to dig a trench within the floor for the water reservoir degree so the pond liner sits under the bottom 20cm (8”) with the outlet on the identical degree as the bottom, this fashion you need to use solely so the 2 ranges of sleepers as an alternative. By comparability, such a design makes use of solely 6 full-length railway sleepers.
  • Galvanised or coated metal raised backyard beds of assorted dimensions are additionally generally used so long as they’re of satisfactory depth. Sometimes one thing round 70cm (28”) excessive works effectively as this enables for an excellent depth of soil, and sufficient of a lip above the soil degree to carry mulch in place.
  • If utilizing a small container which isn’t that deep you wont be needing a 20cm (8”) deep water reservoir, you may scale it right down to go well with the size of the container.

Wicking Bed Design

Wicking beds design displaying the parts of the system

If we have a look at the wicking mattress design proven within the diagram, we will see it’s constructed of a number of layers or ranges. One of the best ways to elucidate how the wicking mattress system work is layer by layer, in the identical means that it’s constructed.

  1. The ‘shell’ of a wicking mattress is a pre-constructed or pre-fabricated raised mattress, it may be manufactured from metal, wooden, no matter is powerful sufficient to carry the required quantity of soil.
  2. The raised mattress ‘shell’ is lined with pond liner in order that it could possibly maintain a big quantity of water. It turns the raised mattress into a really massive watertight container.
  3. A gap is drilled via the raised mattress and pond liner to suit the overflow pipe (threaded tank inlet or bulkhead becoming), at a top of 20cm (8”), which permits the water to movement out when the water degree will get too excessive.
  4. The pond liner water reservoir is full of coarse scoria (a porous purple volcanic rock) to the peak of the overflow pipe. This layer will maintain the water. the water sits within the areas between the scoria, and wick it upwards. The scoria layer additionally serves as a structural assist to carry up the soil above it away from the water under.
  5. The L=formed inlet pipe is put into place earlier than the scoria is laid down, it serves as a water inlet to fill the water reservoir with water. The vertical pipe is joined to the horizontal pipe with a 90-degree elbow be a part of. The decrease horizontal pipe has holes drilled proper alongside its size so water drains out extra simply.
  6. The scoria layer is roofed with geotextile cloth or shade fabric to maintain the soil layer above it from falling into the scoria layer water reservoir – basically it’s a barrier that separates the water under from the soil above.
  7. The soil then fills the mattress to a degree just under the sting of the pond liner, so the pond liber sits barely greater than the soil degree.

The wicking mattress is full of water from the inlet pipe to fill the water reservoir, when it’s full, some water will movement out of the overflow outlet. The water will then wick upwards as excessive as it could possibly to maintain the soil damp.

By understanding how a wicking mattress works, we will get a greater concept about how we wish to design one and decide the portions of supplies required tor building.

Wicking Mattress Supplies

Wicking beds require plenty of supplies to assemble, and because of this, they aren’t low cost.

To assemble a wicking mattress you will want the next supplies:

  • Raised backyard mattress – prefabricated metal raised backyard mattress or DIY timber raised backyard mattress
  • Pond liner – both PVC or the costlier butyl rubber (these have very lengthy warranties on then and are designed to not leak. Whereas some folks use black builders plastic, it’s not as sturdy as pond liner and never really useful). You’ll need sufficient pond liner to line the edges and backside of the raised mattress. So, your width of supplies will must be (width of mattress + 2x the peak), and the size of pond liner will must be (size of mattress + 2x the peak).
  • Scoria (Coarse Grade) – it is a porous volcanic rock that fills the water reservoir, the water occupies the scoria layer and wicks upwards. You’ll need sufficient to fill the raised backyard mattress to a top of 20cm (8”). To work out the quantity in litres,use the next formulation: (size of backyard mattress (cm) x width of backyard mattress (cm) x 20cm)/1000, so for instance a 2mx1m backyard mattress will take (200*100*20)/1000 = 400L of scoria. or 0.4 cubic metres.
  • Geotextile cloth – separates the soil from the scoria-filled water reservoir. Geotextile cloth is artificial and doesn’t break down, which is necessary. Geotextile cloth is bought as positive grade weed mat which seems like see-through fabric (it does NOT seem like plastic) and might are available in a number of colors, typically grey-black or white. As it’s fairly skinny it’s a good suggestion to make use of a double layer of geotextile cloth . If geotextile cloth is unavailable, you need to use shade fabric with a excessive shading issue as attainable corresponding to 90% shading shade fabric, because the holes are smaller. Whichever materials you utilize, you will want sufficient to cowl the underside of the raised mattress and prolong a little bit up across the sides by not less than 15cm (6”).
  • Soil Combine – use a excessive grade soil with an excellent degree of natural matter in it. Ideally, a mixture of 50% premium soil, 25% natural compost and 25% natural cow manure will give your vegies an excellent begin.
  • Water Overflow Outlet Becoming – use a 20mm Threaded Tank Inlet (Bulkhead becoming) and get a drill with the suitable drill bit or gap cutter to drill a gap to suit the becoming into the aspect of the raised mattress.
  • Water Inlet Pipes – use two items 50mm (2”) PVC pipe, joined by a 90-degree elbow joint. The vertical phase of pipe ought to prolong above the soil line at a top that enables the gardener to comfortably pour water into it (not too excessive), however not so low that it’s misplaced amongst the vegetation. The horizontal part ought to be roughly half to 3 quarters the size of the mattress, and ought to be drilled throughout and over its size with holes roughly 10mm-12mm (3/8”-1/2”).
  • Instruments required – spirit degree for levelling the backyard mattress and scoria laver, a drill and applicable drill bits and gap cutters as mentioned above, a set of small spring or screw clamps for holding the pond liner in place whereas filling, and scissors to chop pond liner.

After we’ve got gathered the required supplies, we will then start building. Enable a number of hours for building when you’ve got by no means constructed a wicking mattress earlier than as you’ll be studying as you go. As soon as you might be aware of the method and have developed and refined a system that works for you, you’ll have the ability to construct them relatively rapidly. The two wicking beds within the following directions had been constructed at a kindergarten with a colleague (and plenty of little youngsters with tiny plastic spades and buckets) in a little bit over an hour!

Wicking Mattress Development – Step by Step

On this tutorial article we’ll be utilizing a galvanised metal raised mattress as the bottom for our wicking mattress.

Additionally, for ease of building, we’ll use a barely less complicated design the place the water inlet tube is only a straight pipe with no bend in it, as proven within the diagram under:

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Wicking Bed Design2

Step 1 – Place or assemble the raised mattress within the desired location, as soon as it’s full of soil will probably be immovable!

Step 2 – Be certain that it’s degree through the use of a spirit degree – place the spirit degree crossways and lengthways and at numerous angles to find out whether it is wicking mattress must be degree as a result of it’s going to maintain water at a particular top, whether it is angled it’s going to drain out one aspect and be too dry on the upper aspect or not drain correctly and be wetter on the decrease a aspect of the mattress is low and wishes elevating, carry the mattress barely and pack extra soil beneath to raise it, whether it is excessive, dig some soil out.

20140904_105443 When you’re questioning concerning the 4 white tubes inside the highest fringe of the raised mattress, they’re a part of it, it’s bought that means. The vertical tubes are used for attaching versatile pipe from one aspect of the mattress to the opposite to make a half-circle tunnel -shaped body to assist a protecting materials corresponding to hen or insect netting. shade-cloth or plastic.

Step 3 – Drill gap within the aspect of the raised mattress, 20cm (8”) above the bottom.


Step 4 – Lay down the pond liner contained in the raised backyard mattress and test that it matches correctly.


Step 5 – Set up the 20mm threaded pipe outlet (bulkhead connector). Lower a gap within the pond liner simply large enough to suit it via the opening, no bigger, and make sure that the rubber washer of the becoming is in opposition to the pond liner to make sure a watertight seal.


Step 6 – Put together the water inlet pipes – if utilizing the vertical modified design, drill 10mm (3/8”) holes throughout the final 30cm (12”) of the 50mm (2”) extensive PVC pipe, size ought to prolong excessive sufficient above raised mattress to permit environment friendly watering with out reaching too excessive or pushing crops out of the best way to search out the watering inlet.


If utilizing the extra widespread design of an “L” formed water inlet, use two lengths of pipe and an elbow be a part of. The horizontal part ought to be roughly half to 3 quarters the size of the mattress, and ought to be drilled throughout and over its size with holes roughly 10mm-12mm (3/8”-1/2”). Be part of the 2 pipes with the elbow be a part of, simply push-fit the items collectively, a friction-fit is adequate.

Step 7 – Lay down a skinny layer of coarse scoria over the pond liner. This may mattress it down and put a protecting layer of scoria over the pond liner in order that it could possibly’t be broken by the PVC inlet pipe.

Essential – This modified design used just one shorter piece of inlet pipe and no elbow joint for the pipe, it’s ‘I” formed and never “L” formed as within the earlier design, so the reduce finish of the pipe is pointing straight down onto the pond liner, be sure that there’s an satisfactory layer (5cm or 2”) of gently packed-down scoria between the top of the pipe and the pond liner to keep away from puncturing it if the pipe is pushed down!


Step 8 – Clamp the pond liner to the highest edges of the backyard mattress proper round utilizing small spring or screw clamps to maintain the pond liner in place whereas the mattress is full of supplies.


Step 9 – Fill the backyard mattress with coarse scoria to the peak that’s degree with the overflow outlet. Ensure that the scoria layer is pretty degree and even.


Step 10 – Lay down geotextile cloth (or shade fabric) over the scoria layer.


Step 11 – Wrap effectively round inlet pipe, enable the material to come back up across the pipe to forestall any soil getting into the scoria layer.


Step 12 – Cowl the scoria layer with two layers of geotextile cloth (or a single layer of dense shade fabric) and prolong it up across the sides of the pond liner by not less than 15cm (6”).The geotextile cloth should be tucked in throughout the aspect, the place the scoria meets the raised mattress partitions. This may safe it in place, and permit the wicking to work correctly. Simply push the underside half or the vertically extending sections between the pond liner and scoria. That is to make it possible for no soil can get into the scoria layer.


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Step 13 – Verify that the scoria layer is degree. If there are any excessive spots, pat them down. Low spots will be raised by urgent across the sides of the low space to push scoria into the world to fill it.


If the scoria is way too uneven, carry a piece of the geotextile cloth, degree the scoria layer, after which put the geotextile cloth again in place.


Step 14 – Verify as soon as extra that the scoria layer is degree below the geotextile cloth.


Step 15 – Start filling the raised mattress with the soil (50% soil, 25% compost, 25% cow manure combine or your individual mix), guaranteeing that the pond liner is saved in opposition to the partitions of the raised mattress as you fill with soil.


20140904_123756 The blue plastic pot on the prime of the water inlet is there as a cap to forestall dust and different objects getting into the water reservoir.

Step 16 – Trim off extra pond liner with scissors leaving about about 3cm (1-1/4”) of pond liner the soil line.


Step 17 – Wicking mattress accomplished and able to plant and water!To get the system to wick correctly, it is advisable evenly moist all of the soil first by gently watering the soil from above repeatedly till water begins working into the scoria layer.

As soon as the soil is evenly moist, fill the water reservoir via the inlet pipe till water begins to movement out of the overflow pipe. Vegetation up the wicking mattress and mulch your crops to preserve moisture, then sit again and calm down!



Getting Extra Out of Your Wicking Mattress

Mulch – The rationale why there’s a appreciable lip or edge above the soil degree , round 10cm (4”), is to permit the mattress to carry a pleasant thick layer of mulch above the soil. Mulch retains the moisture within the soil, prevents evaporation, and conserves water, and the aim of constructing a wicking mattress within the first place was to cut back watering. When you’re constructing your wicking mattress within the heat seasons, at all times mulch!

Mulch with a layer of mulch round 5-7cm (2”-3”) so the water lasts longer, and your crops roots keep cool. The mulch can even break down slowly and add vitamins to the soil. For mulch materials in a vegetable backyard mattress, you need to use pea straw, lucerne, hay or sugar cane mulch.

In-soil worm farms – you can too assemble worm farms immediately within the wicking mattress utilizing worm tunnels (see article Construct a Worm Tunnel Vermicomposting System) in order that the entire wicking mattress turns into a wicking worm farm, that means the earthworms generate worm castings, top-of-the-line recognized fertilizers, throughout the backyard mattress itself!

Water recycling – the water that flows out of the water overflow outlet shall be loaded with fertiliser so you may run that water right into a bathroom backyard, reed mattress system or a backyard mattress within the floor for moisture loving crops (in the event you get sufficient water overflowing!)

Additional rising house – wicking beds, like different raised beds, can assist frames or trellises to develop climbing crops on corresponding to beans, peas, cucumbers, watermelon and every other edible annual climber you fancy. Needless to say you cant hammer stakes or poles into the wicking mattress itself, that may punctuate the pond liner and destroy the watering system. The body, trellis or assist has to both be anchored into the bottom or hooked up to a wall behind the wicking mattress.

Protecting covers – as with different raised beds, you can also make a body to assist hen netting or insect exclusion netting to guard the crops in your wicking mattress from pests. One other chance is to make use of clear greenhouse plastic to make a cloche tunnel for prolonged season rising.

Wicking Mattress Upkeep

To take care of a wicking mattress, flush out the entire system not less than every year. If the wicking mattress is undercover and never uncovered to rain, which helps flush it out naturally, think about finishing up the duty maybe twice a yr.

To clear away excessive ranges of salts which might be increase on the prime layers of the soil, water from above to clean them out into the water reservoir and out of the outlet pipe.

Additionally, keep in mind to go simple on the fertiliser when feeding the backyard mattress in spring and autumn, as fertiliser ranges can accumulate in wicking beds as a result of each little bit of fertiliser that you simply put in keep within the system until it’s washed out.

Apart from that, preserve a wicking mattress similar to every other raised mattress.

Now that you recognize whether or not you actually do want a wicking mattress, the way it works, and easy methods to construct one, the remaining is as much as you! Completely happy rising!

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