Open Book planting bed explained
This alternative planting bed design is a hybrid idea that sits between the traditional ‘open soil’ and the new fad of boxing soil in “Raised beds”. It has I believe many advantages over these two currently accepted bedding approaches.
In a nutshell it is a sunken bed within the grass level of your plot. The soil from this newly dug bed is then heaped either side of a sunken “leaky” wooden trough made from half a pallet, see annotated cross sectional diagram.
This modified pallet is sunken centrally in the spine of the bed to the depth of the first slat (3-4 inches), dividing it into two parallel beds. Because it is a paired bed design it ideally needs to be positioned with a “north-south” orientation so that both sides receive an equal share of full sun. A section of box cladding tinware is cut from around the ridge and is used as our “water deflector”. It is screwed to the base of our pallet using 10mm plastic spacers to create the gap and completes the “leaky” trough. The pallet is then filled about halfway with conker sized stones collected from riddling your soil. The tinware deflector retains the stones making it easier to remove the divider at the end of the season (Sept/Oct). As well as guiding and slowing the water from your periodic watering (early spring / high summer) directly into the root area of your plants.
see photo of 2017 version of “Open book planting bed” system in a U-Bend shaped bed.
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<< LATEST NEWS: UPDATE for 2017 >>
After observations and realisations made during the 2016 growing season I have made a crucial addition and a slight adjustment to the shape of the “Open book planting bed” soil profile.
After getting good growth from this U-Bend shaped bed last year (2016) I did however notice that I was having to water the bed every couple of days during the summer compared to the year before. The divider was acting as a very efficient water evaporator. The bed had a East-West orientation meaning the full length of the divider (south facing side) was in the full glare of the sun, Also along with the more curved shape of the soil bed, angled towards the sun. By adding the perimeter edging using the Wood chip sock idea and flattening the soil profile and swinging the bed around 90 degrees to the more optimal North-South orientation, solved these soil drying issue.
What’s so special about this idea ? Its just soil heaped against a leaky wooden trough ?
The concept is similar to Keyhole Garden beds that are popular in Africa. Keyhole Gardens are a low tech implementation of the low maintenance “Plant & Play” vegetable growing philosophy often with some form of autonomous watering system. Where my design differs is in the use of the pallet wood divider which I believe is acting as a sort of “moisture level” 2 stroke engine / pump. On the first stroke water is directed into both beds. Then the combination of the wind passing over the divider and the absorbent nature of the wood and the heating of the divider and the stones by the sun, is setting up a positive gradient (a suction) horizontally across the bed. This increased ebb and flow of moisture levels across the plant roots appears to be liberating more minerals from the soil. In comparison to “raised beds” where boxing in your soil or raising the level of your soil bed too high, works against your water profile and reduces this natural wicking effect. In the open soil approach water is evaporating from a large surface area across your whole plot. I believe my design sits within a “Goldilocks zone” of optimal water use.
This teenage African girl from Rwanda has constructed about the most effective KG design in my mind, without even thinking about the science. There is nice positive growth and appears to require none or very little watering.
My “Open Book planting bed” design with its recycled pallet divider is easier and quicker to construct and without any of the heavy lifting that this little girl and her family have had to do. No building a one metre high mound of soil for starters (I realise this may be a requirement of the design due to heavy early evening tropical showers).
These pallet wood dividers are only in the soil for 7 months from April to October. Using the rope handles they are easily pulled out of the soil and stored under a tarpaulin for the winter and the bed is then seeded with a green manure to over winter.
History, how did the ‘Open Book planting bed’ idea start.
Basically the germ of an idea started when I thought that the furrow between two parallel rows of potatoes was a waste of space. If I could insert a wooden partition between the two ridges and then heap the soil either side of this wooden partition, I wouldn’t have to spend time earthing them up. They would have a deeper section of soil in which to grow and only one sides worth of exposed potatoes would need earthing up rather than two. The cheapest (free) and most readily available wood to me was pallets.
Its was only once I started experimenting with this soil-against-a-wooden-box way of creating planting beds and was getting more robust growth that I started to realise it had a long list of advantages over the more traditional existing approaches.
“This is a hybrid idea to structuring planting beds. A cleverly simple idea with a long list of benefits.”
Advantages of using the pallet wood divider in combination with wood chip socks to create an Open Book planting bed.
A “little bit of magic” is taking place with this design. The wood chip sock borders are acting as water buffers and in combination with the quick drying central divider is creating a positive water gradient (a suction) horizontally across the bed. Leading to optimal growing conditions. This designs appears to be acting like a low-tech, simplified ‘wicking bed’.
More efficient use of water through clever design. The stone filled void of the pallet allows water to quickly filter directly to the soil around the roots of your plants. Not being wasted just watering the top couple of inches of your soil. Which avoids a soil surface crust forming or anaerobic conditions from water saturation. Also it works with the water table at your plot not against it (eg. raised beds).
Watering indirectly through the pallet may also limit the spread of fungal spores that cause dampening off. Allowing the use of rain collected non-mains water. Potentially you could add a layer of stone, gravel and sand into the pallet void to further filter your water, removing potential pathogens.
This method is scalable. You only open up as much soil as your actually going to plant into. Especially on those ‘harder-to-dig-over’ virgin allotments. As you create each paired bed you are opening up a 3-4 square metre area of soil.
A raised soil profile, banked soil, seems to suffer less from water logging / soil compaction. Also the soil properties of each half of the bed can be easily adjusted to suit the current crop being grown.
The ‘scoop & heap’ soil profile makes more efficient use of the top 4 inches of soil (top soil) which contains the richest soil. No need to fill your bed with extra soil either bought or borrowed from other areas in your garden / plot.
It is easier (quicker) and cheaper to construct than a raised bed, see Buiding divider. Especially if you buy it already built. Also it recycles pallets that would have ended up in landfill.
Dressing (adding manure) and digging over the bed or weeding the crops is easier as you have access on 3 sides of your banked soil. No more banging your shins on the wooden sides of your raised beds.
The sunken pallets also create an additional physical barrier against snails & slugs. I have noticed that the inner beds suffer very little slimy critter damage compared to the outer beds.
You can walk along or lean on the buried pallet spine to reach plants, avoiding soil compaction when watering or picking vegetables. Also the design requirement to fill the pallet void with stones provides a reason to collect stones as you dig / riddle your plot.
A uniform bed size, 28″ x 94″ (inches) or 70cm x 3.3m, makes it easier to quickly divide up your plot when at the planning stage when you first start. The width of the paired bed is 1.5 (including the width of the pallet divider).
“Allotment Guardianship”. Basically if you give up the allotment you have left it in a better state (not worse) than when you took the allotment on. Its means the next person to take on your allotment finds well defined (1.5m x 3.3m) growing beds with soil that is easy to turn over.
With this design you are effectively getting a planting bed with three zones of differing moisture profiles. Wolf Spiders love these pallet dividers for some reason. I’m not sure if this is benificial or not. Do wolf spiders eat caterpillars ? Every time I walk past them I see at least a couple scurry back under the stones.