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By October 12, 2017 0 Comments Read More →

How to Build a Dehydrator

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Making the most of an abundant harvest is the name of the game for all home farmers, and this month reader, Chris Southall ( shows us how to do it in style with a ‘powered’ solar dehydrator

In addition to bottling and jamming, we are also preserving more and more fruit by drying here at EcoDIY. I recently decided to build a dehydrator which used surplus electricity from our solar PV systems to boost the production from our solar dryer. The dehydrator was made from scrounged, recycled materials such as polycarbonate sheeting and a second-hand fan fire from a car-boot sale.

  • 2 square metres (approx.) of polycarbonate sheeting.
  • I get lots of second-hand polycarbonate sheeting free from firms on our local industrial estate that install conservatories; you could also try email groups such as Freecycle or Freegle. Polycarbonate sheets make great cloches, and rot-free building material for lots of other projects.
  • 3 mesh squares for the removable shelves.
  • I used mesh from eBay intended as varroa screens for beehives. These cost about £6 each and are approximately 45cm square. Any other stiff mesh will do.
  • 14 metres (approx.) of 20mm x 40mm batten for the frame.
  • 2 hinges (recycled!).
  • A small piece of chain and a cup hook for the door catch.
  • A low-power fan fire (from a-car boot) – 1kW or less (if possible).
  • 2 pieces of chipboard, blockboard or plywood the same dimensions as the shelves.

The precise dimensions of the dehydrator box are not critical, but will be determined by the size of the mesh you are using for the shelves; these are the measurements for the components that I used.

  • Polycarbonate sheeting cut to size with a Stanley knife as follows:

Back and door – 520mm x 810mm.

Two sides – 465mm x 810mm.

Top – 46mm x 46mm (the same size as the shelves, plus 5mm each side).

  • 2 plywood or chipboard squares 46mm x 46mm (the same size as the shelves, plus 5mm each side) for the bottom and the diffuser shelf.

I used 20mm x 40mm batten throughout, but this is not critical – if you have a different size available, then adjust the lengths of the pieces accordingly.

Cut the batten for the frame and shelf supports as follows:
  • 6 pieces 814mm long for the vertical frames.
  • 10 pieces 458mm long for shelf and top supports.
  • 2 pieces 445mm long for the top and bottom of the door frame.
  • 2 pieces 425mm long to support the top front and back.
  • 6 pieces 38mm long to screw to the front and back of the shelves and stiffen the mesh.

1           Drill 9 evenly spaced 40mm holes in the top polycarbonate and in one of the boards. I stuck small pieces of mesh over these holes to keep out flies and wasps. I also taped the edges of the mesh with aluminium tape, where they were sharp.

2           Cut a square out of the bottom of one of the side polycarbonates to allow the fan fire to be inserted later.

3           Screw the frames and shelf runners to the side polycarbonates, as shown.

Assembling the sides, stage 1.

4           Screw the back and top polycarbonate to the sides, then screw through to the wooden base.

Assembling the sides, stage 2.

5           Add the second square of board (with the 9 drilled holes) about 150mm up from the bottom – this spreads the hot air from the fan fire.

6           Assemble the door frame onto the door polycarbonate.

7           Fit the door hinges and the chain for the door catch.


Rachel, our ‘WWOOFer’, making apple rings.

The dehydrator must be kept out of the rain, but in the sun (if possible), to gain extra drying benefit from the solar heat. We have used our own dryers to preserve our surplus:

*           Apples and pears, as rings and slices cut to about 5mm thick.

*           Figs, apricots and Victoria plums, cut into quarters and with the stones removed.

*           Grapes, gooseberries and cherry tomatoes, split in half.

*           Onions, sliced thinly.

*           Mushrooms, either whole or sliced .

*           We also make fruit leather by sieving cooked fruit combinations and drying a 5mm layer on a non-stick baking sheet ‒ apple with raspberry or blackberry, and pear with blackcurrant, each work well with a minimum of added sugar to avoid sticky leather. Do experiment with other fruit and vegetables, too, though.


A finished fruit leather.

We control the temperature inside the dryer by covering the holes in the top as needed. After drying, we store the fruit and onions in glass jars, and the tomatoes in the freezer, as we have read there can be a small danger of food poisoning with dried tomatoes. We cut up the dried fruit to use in baking (Rosie’s chocolate beetroot cake is to die for) or breakfast cereals, and we save many ‘food miles’ by not buying raisins from California.


Chris and Rosie are developing a life of suburban self-reliance in Clacton, Essex. They are a permaculture demonstration project and WWOOF and HelpX hosts. You can read all about their progress in the March 2016 issue of Home Farmer, or visit to find out more.


About the Author:

Ruth Tott is the publisher of Home Farmer Magazine, and together with her husband, Paul Melnyczuk, Editor,is founder of the company. But her background is far removed having specialised in Costume History with a Post-Grad diploma in Museum Studies to boot. A far cry from looking after chickens, growing veg and making bread!

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