DIY Landscaping Boulder (made from unlikely supplies!)

April 27, 2021 1 By EngineerMommy

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I’ve been on such a DIY kick recently. I’ve made those textured vases from thrift store glassware, those shimmery crystals from dollar store rock chips, that spring terrarium, those simple spring wreaths, so much more.. and my list is not anywhere near done! Today I’m going to show you how to make a DIY Boulder using … well, keep reading for all the deets, friends!

First a disclaimer! Ok, maybe boulder is a bit much. This piece is not huge but it’s not a small rock either. It’s about the size of a shoe box. By the way, where did I get the idea to make my own boulder? Fair question! Well I wanted to work on our flower bed and give it some more visual interest. I saw ones like these online…

…and knew I could make it for much less. So I went about gathering some materials for the mold. I used literally whatever I could find around the house.

Now keep in mind that ideally you want to avoid items that can decompose or break down over time (cardboard, paper, food scraps, etc.) Good choices include plastic buckets, styrofoam packaging material, etc. Here’s what I included in my mold: plastic buckets, cardboard box, random scrunched-up packaging paper, etc. I plan to take out the mold once the builder is formed so in this case, the mold material is less consequential. Here’s my mold:

Now when I first started this project, I had pre-mixed thin-set mortar (used for tiling applications) around the house so I slapped some of that onto my mold and waited..and waited..and waited. It was taking forever to dry. Then I discovered that it’s better to use something like rapid-set construction mortar (similar one linked) so I switched to that. Here’s the boulder after one coat.

Dry in one hour! Perfect! I did another coat of the mortar to fine-tune the bumps and hills and topography of my boulder. Here’s the boulder after the second coat.

I sprayed some of this stone-textured spray paint on top for added texture. Then I used three different colors of matte gray acrylic paint (light, medium and dark.) I blotted these onto the boulder in an organic fashion, trying to mimic a natural appearance of a boulder occurring in nature. 

It’s not perfect but I think it’s a pretty good first attempt. My cost out of pocket? Just $11 for the rapid-set mortar – and I have a TON of it left over! Much better than the ~$100 for a store-bought version of a similar size!

I sprayed a final coat of clear matte sealer on top and it’s all done! I may or may not be working on a larger-scale version! 😉


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