seed planting and propagation
seedling propagation
how to make an aquarium heater
Two Seedling Tray propagation box 1.
A single aquarium heater can be used to heat two seedling trays at once.  Below is information on how to make a two seedling tray heated propagation  box using an aquarium heater.

Materials you will need
$20 Stackable storage crate: 32 or 54 Litres
$50 Two Grow Top lids and trays (@$25 each) (you will need these whether you make this heating box or buy a commercial one)
$6 42 x 19 mm wood: Two pieces 640 mm & two pieces 330 mm long
$8 89 x 19mm wood: One piece 370 mm long
$4 40 mm screws: 8 (suggest button head screws)
$30 Aquarium heater: 50 to 100 Watts. (wattage size will not make a great deal of difference in terms of electricity use, larger wattage heaters will simply be on for less time)
$7 Rubber window seal strip (optional)
$125 TOTAL
These are only approximate costs. With a bit of shopping around and the use of scrap wood you could probably get the cost down to around $100.  Costings done in August 2016.

Building the propagation box
  1. Photo of a stackable crate with a piece of wood across the centre.
    The crate with the piece of wood in place across the centre.  The top side of the wood is just below the lip of the crate level with the internal ridges.

    Photo of screws holding wood in place on stackable crate.
    The screws holding the piece of wood in place.

    Photo of an aquarium heater propagation tray with frame.
    The top frame in place with detail of the rubber seal displayed as an insert.
    Select a stackable crate.
    Stackable crates come in various depths but have a uniform top with internal ridges at each end so they can be stacked on top of each other.

    Two common sizes available are 32 and 54 Litres.  The 32 litre size is the preferred option as it holds enough water without being too big.
  2. Fix the 89 x 19 mm piece of wood in a horizontal position across the centre of the crate using four screws.
    The top of the wood needs to be level with the internal ridges at each end.

  3. Build a rectangular frame to sit on top of the crate and screw it in place.
    Using the 42 x 19 mm pieces of wood build a frame so that the internal measurement is 570 x 330 mm.

    This internal measurement will allow you to place two standard seedling trays on top of the crate with the wooden strip in the centre holding up one side of each seedling tray and the internal stacking crate ridges holding up the other side.

    The upper lips of the seedling trays will sit over the top frame to give a reasonably snug fit.
  4. Place the frame on top of the crate. Check that the two seedling trays fit properly then screw the frame to the top of the crate using four screws.

  5. Run window seal around the inside of the frame.
    An optional extra is to run a strip of rubber window seal on the inside of the frame to create a really tight fit.

    These seals come with a self-adhesive strip but the glue is not waterproof so the adhesive strip will not hold in place for long.  If you use silicon or a waterproof glue to adhere the strip to the sides if will save having to glue it back on when the non-waterproof glue fails.   

PAGE CREATED 2015-10-22  Page modified 2016-08-04