using leftover deck boards for walkway

I think the less contact you have with the soil, the longer the 4x’s will last. I would lay paving blocks on the ground and rest the 4x’s on them. 6 blocks space 4’ apart will be sufficient. Killing the grass under the walkway and covering the area with gravel will keep weeds from growing up through the walkway. There are other more intensive ways of doing this, but this is the most less cost way and easiest way to do it.

In addition to MrRon’s recommendations, I would recommend you seal the 4×4s on ALL FOUR FACES before assembling the walkway. 4×4s are notorious for warping and twisting and turning into boat keels! Good luck!

Cheers!

-- Dave; Lansing, Kansas

When ever I need to do something like this I get bag(s) of very fine leveling gravel at a big box store. Dig some of the loose topsoil out and replace with some of the gravel. It provides a base that is firm and easy to adjust as long as you keep it at or slightly below the surrounding soil. Use various sizes of concrete blocks/bricks to achieve grade and you can use some pressure treated to create tinner spacers if needed. It should stay solid and keep your wood off the soil. Noe: I am in the south and have a very minimal freeze depth. If you have a deep freeze zone this may need to be modified to have good results.