Pallet wood Hydro-driver theory, construction guide

Theory behind the Pallet wood Hydro-driver

The Pallet wood Hydro-drivers main task is as a moisture level moderator (Hydrostat). It achieves this using a physics principle called Stack Effect. How this works is that as the sun comes up it heats the stones and the air in this narrow and tall pallet void creates an uplift of warmed moisture heavy air. The absorbing but drying-on-one-side quality of the wooden bottom slat (-negative moisture zone) gradually exerts a hydrostatic pull across a large section of the soil bed sucking water from the moisture +positive Wood chip sock borders horizontally across the growing bed leading to moderated, non-saturated and consistent moisture levels within the growing bed. This hydrostatic pull also seems to be liberating nutrients and minerals from the soil more rapidly. In comparison to boxed-in “raised beds” with their easily over filled soil levels working against your plots natural water table and halting the natural wicking effect. In the traditional open-soil approach water is wicking away from a large surface area across your whole plot. I believe my Pallet wood Hydro-driver design helps sustain a ‘Goldilocks zone‘ of optimal moisture levels and steady transpiration.

The divider also acts a platform for treading on or hooking on attachments such as my g.easel (Gardeners Easel) 4-in-1 design; Squash Trellis, Bean frame, Windbreak and (G. Hamilton) Cloche design.

Starting with a basic pallet

There are a few different types of pallet designs and we require a specific type that is generally used to transport bricks. It is called a Standard 2-way entry pallet. It is different from the majority of pallets in that it has 4 or 3 strong struts that the pallets slats are nailed too (see image below). You will also notice the 3 basic tools required to build our half pallet stone stack; Wood saw, claw hammer and crow bar. I am also using a nearly designed tool called a “Roughneck Demolition and Lifting bar” that makes levering up the slats easy and without damaging the slats.

The Pallet wood Hydro-driver is sunken centrally in the spine of the planting bed to the depth of the first slat (3-4 inches) dividing it into two parallel beds. 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 and with the nylon handles at either end of the divider makes it easier to remove at the end of the season (Sept/Oct) and stored under cover.


There are two ways of creating the bottom of the trough.

<< CLICK on image to zoom in >>

This is how the completed divider should look after all that fettling…

Completed pallet wood divider mk2.0

Pallet divider mk2

Current pallet wood divider design mk2.1










#1 How to dismantle a Standard 2-way entry pallet

Using the Roughneck bar to prise up the slats away from the vertical struts.

For the nails left behind in the struts, give them a couple of taps. It will drive them in a little bit. This make it easier when pulling them out with a claw hammer / crowbar. Breaks the rust / wood meld.

Collecting the old nails for reuse.

The pallet very nearly dismantled

Fully dismantled pallet

#2 Constructing your Pallet wood Hydro-driver

You will need x4 slats + x1 support strut. The slats are 1.1m so will not need cutting to size.

Cutting the strut in half with a 45 degree angle to create the two divider supporting legs. 16″ long is the measurement.

Assembled wood ready for construction

One half assembled

Wood of divider put together


Types of deflector, Plastic and a tin version

Looking into the pallet divider at the water deflector

Types of water deflector. Plastic cable guard vs plastic coated metal corrugated box cladding.