How to Make a Hotbed

• Decide on a proper location . The hotbed should have good sun exposure facing south and also good protection from northerly and westerly winds. Must have good drainage, so a slightly sloped is a good idea.
• Next you will need to determine the size of your hotbed. If you have an old window sash you could use that (remember your top lid has to be the outside dimensions to fit like a lid ).
• Once your dimensions are determined you will want to lay it out in its location.
• Before you start excavating you will have to make the decision on how the heat will be provided. There are basically 2 methods.
• Manure, which people have been using for hundreds of years. This method is fine but you will have to monitor temperature closely and change once a year. If manure is something readily available to you and can get for free this may be for you.
• Electric Garden Heating Cable (generally around $25) come with built in thermostat, which regulates heat more consistently. You will have to make sure you could provide a power source.

         The reason why this needs to be determined before your digging begins is to how deep you will have to go. Manure you will have to dig 20 to 24 inches deep, whereas with a heating cable 14 to 16 inches.

                      This illustration shows the Manure method as example

• Once your determination is made excavate your layout to the depths listed above. Dig the corners for your  4 posts deeper to secure.
• If you notice in the illustration above it is sloped from front to back. A good pitch is 1" per foot.
• It does not have to be flush to the ground. I recommend 3 to 4 inches above, and a couple of inches of gravel under manure for drainage.
• Now secure your 4 posts and square (I use the 3,4,5 method, but steel square works). Tamp if needed.
• Next you will need to nail (or screw) the boards to the 4 posts to make walls extending from the ground. I would leave my board 3 to 4 inches below the grade when done. Any kind of wood will do, (plywood, pine, cedar, etc.) whatever you got laying around. DO NOT USE TREATED LUMBER.
• When walls are complete attach top lid using two hinges to secure. Lid should have glass, or transparent plastic to allow for sunlight.
• Filling hotbed :
• For Manure Method :
• Fill with enough (farm fresh ) manure leaving 9" from top front. Tamp lightly and water. Mixing straw into manure also works well.
• Mix equal amounts of topsoil, peat moss, and sand to fill hotbed leaving 3" from top front.
• Cover with lid and let sit for 4 to 5 days checking soil temperature periodically. You will have to buy soil thermometers (2 or 3 should be good ), and place them 2 to 3 inches into soil in representative places to check heat.  When soil temperature drops to 75 degrees or slightly under, bed is ready for seeding.
• For Electric Cable Method :
• 3" of course gravel on bottom (use rock which you acquired during digging).
• 4" of sand
• Install heating cable in up and down fashion approx. 5" apart on top of sand.This will help disperse the heat. Remember to be able to access your thermostat control, and run to power source.
• Add 1" of top soil evenly to cover cable
• Add wire mesh to top of soil to protect from digging into.
• Mix equal amounts of topsoil, peat moss, and sand to fill hotbed leaving 3" from top front.
• Cover with lid and turn on heating cable checking soil temperature periodically. You will have to buy soil thermometers (2 or 3 should be good ), and place them 2 to 3 inches into soil in representative places to check heat.  When soil temperature reaches 75 degrees or slightly under, bed is ready for seeding.

 Note : 

• If you wanted to make a Cold Frame at the same time, instructions are exactly the same with the exception of :
• No heat source is required
• Excavate 6" deep.
• Mix equal amounts of topsoil, peat moss, and sand to fill cold frame leaving 3" from top front.

• Enjoy and Good Luck on you growing season.

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