Here’s how we built a bunch of mobile micro forest gardens for the 107 Rooftop Garden – complete with wicking beds.
Our challenge with this design was to build tree planters that could move around to make space when needed, while providing shade, beauty, pollination and food.
Mobile Forest Garden Wicking Planters:
- Pallet undercarriage so they can be moved around by pallet trolley
- Stainless steel tank planter tops (thanks, Tankworks!)
- Wicking beds for consistent root moisture, given site exposure
- Planted with climax fruit or nut tree, surrounded by edible herb + pollinating plants guild
- Mulched heavily to minimise evaporation
- So darn beautiful
Nick came up with this design to maximise the various constraints + resources we had on site.
The planters needed to be extremely strong + kid-proof, and movable without the possibility of ever rolling and squishing any little fingers, given how heavy they were.
The planters needed to provide movable shade, as well as augmenting the rest of the vibrant food production garden.
The planters needed to be resilient to all weathers – from extreme heat to extreme wet, and still have their trees looking great, always.
The wicking bed factor
We all know what can happen to fruit trees in pots – they get dry and sad unless they’re consistently watered, because their roots can’t access ground water – only what’s in their pot.
To combat this, we decided to use the principles of a wicking bed system inside the planters. Simply put, a wicking bed is a planter box with a water reservoir at the bottom.
You keep the reservoir full of water, the soil above ‘wicks’ the water upwards, and deep rooted plants get the consistent water they need, without constant watering from the top.
With this in mind, we’d asked Tankworks, who made the planters, to install an outlet point 1/5 of the way up the tanks – this would be our draining point, at the top of the reservoir.
To create the reservoir, we first chopped up some junk plastic pallets to support the reservoir ‘roof’.
We then placed a piece of flo-cell (used under soil in rooftop gardens to ensure drainage – thanks Atlantis!) on top. You could use anything inert, flat and strong with small holes in it for this part.
You can see in the pictures above the outlet – to let water drain out if the reservoir gets over-filled.
The reservoir ‘roof’ had two holes cut into it for two plastic pots.
These plastic pots were drilled with holes to let water in – they’re the ‘deep wicks’ of the system, and once filled with clay beads (you could also use sand), will help wick water to the soil when the water level falls low.
Then we covered everything with geotextile (left over from our gabion building) to ensure the soil didn’t drain into the reservoir – geotextile is designed to let water permeate, but to hold particles in place.
Time for the clay beads – we filled each ‘deep wick’ pot with them (they were left over from our aquaponics system build – as said above, you could use sand for these.
Then we put the deep watering system in – basically a domestic hose connection, and a pipe that ends at the bottom of one of the plastic pots. (disregard our quick sketch-up above for this part, the pipes didn’t go horizontal in the reservoir in the end).
This is how we will fill up the reservoir up when the weather is dry.
And then…. soil! Use the best stuff you can get hold of.
Planting the Micro Forest Gardens
So these are micro forest gardens in the most micro sense – one climax tree, and an understorey planting of complimentary + synergistic groundcovers + mid-height plants.
Still the same principles apply as within a larger forest garden planting:
– Keep the connections between each plant species functional and mutually supportive.
– Stack the available growing area in terms of both time + physical space – vary flowering and fruiting phases, plan for the different plant shapes and light needs.
– Obtain a yield. Grow things that will bear food quickly.
– Plant perennials where possible for energy efficiency + resilience – but stack some self-renewing annuals in there too, for quick harvest turnarounds.
We planted bananas, figs, citrus and nut trees as the climax species, surrounded by edible flowers, herbs, berries, vegetables and whatever else we could fit in.
Of course, for new plants in a wicking bed, top watering is still essential until the plants establish themselves.
So we watered all the plantings well, as well as filling up the reservoirs via the deep watering hose connection, until the overflow pipes indicated they were full.
Making the Planters Mobile
Making these planters movable was a bit of a challenge.
Firstly, all that water (and soil, and plants) makes those planters HEAVY. Like, really heavy – maybe even too heavy to move the planter, if it was on castor wheels.
Secondly, this rooftop garden is a public space – so things that can be rolled around, will be rolled around. No matter how nice a ‘please do not roll this planter around it could squish someone’s foot‘ sign you put on them.
The answer seemed to be (as with many things), to put ’em on pallets.
This way, we can move the planters when needed with our trusty pallet trolley, which can handle extremely heavy loads, and maneuverer things into surprisingly tight spaces – but once the planters are relocated, they’re stable.
You can see in the image below the slot down the bottom of the planters? That’s where the trolley fits in.
And finally, we were all done.
These micro forest gardens got constructed and planted at our first Planting Day at the 107 Rooftop Garden – thanks so much to everyone who came along and helped make this garden happen!
A few months later, the micro forest gardens are looking so darn fine – despite a dry Spring and a January heatwave, they’re lush and green and growing fast, thanks in part to their consistent water supply.
Thank You, Thank You…
- Tankworks – for the planter housings
- The Bharani Effect – for dontaing a Micro Forest Garden as part of our 107 Rooftop Garden Pozible campaign
- Atlantis – for the flo-cell + the vertical gardens
- Fresh Landscape Design – for the garden concept designs
- Select Water Tanks – for the water tanks
- Urban Growers – for the help with planting + planning
- 107 Projects for letting us take over their rooftop
- All our 107 Rooftop Garden Pozible campaign donators
- The fantabulous Milkwood Network – for helping install the garden and being highly legendary