DIY SLATE LEDGE STONE PLANTER BOXES

The yard renovation is really coming together, and it feels fabulous to be completing projects instead of laying the base work. Last fall we built these planter boxes out of cinder blocks, with the plan to face them with ledger stone, and recently got around to finishing them.

The stone faces make a big impact, and they are great additional seating in the yard.

Here’s how we did it.

The ledge stone came from SUI, and it’s called California Gold. It wasn’t cheap ($700 for 45 pieces of ledge stone and 15 bench caps) but it would have been a heck of a lot more work for us to cut the pieces ourselves out of the leftover stone from the patio, so we went for it. The plan was to level the stone and use mortar to adhere it to the cinder block. We couldn’t use the pre-made corner pieces because our corners aren’t 90 degrees, so we knew there would be some cutting and fitting to get the pieces to match up on the corners.

Then we dove right in to mixing mortar (and by we, I mean Ryan). It took 8 bags of mortar to do both planter boxes, which was a breeze compared with the task of creating the concrete forms that we tackled last year.

We leveled the stone using shims (since our benches are flat and our patio has a slope to it, and applied the mortar to the backs of the bottom row of ledge stone. Then we just slapped it on the cinder block. Working with mortar is messy and tedious, but we got better at it as we went.

Here are some things we learned:

– The back of the stone and the surface it will be applied to should be damp when you adhere them together. Use a garden hose on mist or a spray bottle to wet both surfaces.

– The mortars consistency is a key element. When we started we weren’t adding enough water (because we were following the directions on the bag). According to the pros, the correct consistency of mortar should stick to the trowel if held at a 90 degree angle (ours made it to at least 80 degrees before sliding off :-)

– Use more mortar on the back of the stone than you think you’re going to need, it should ooze out of the top and bottom when you apply it

– When you drop some mortar (we dropped a lot) in a space it shouldn’t be, don’t wipe it off, once it dries, it’ll be easier to chip off if it’s a glob, not a streak Here is the first planter bed, about 2/3 complete.

We had to cut the top row of ledge stone off so that the bench caps would fit on. Each ledger stone piece has four rows of stone, and only 3 would fit, so we ran each piece through the saw before placing. It helped to have the whole row ready and in place before mortaring down the row.

The corners of the boxes also required some tricky cutting, we had to measure and cut the angles to get the pieces to fit together. I wish I had some better pictures from the process, but it was so messy I didn’t pick up my camera much. We fit the pieces together at the corner, then drew a line with a pencil and cut off the excess.

With all the cuts required, our wet saw came in quite handy. That thing has paid for itself many times over already, and we haven’t even started the kitchen or bath remodels (which will most definitely require some tile work).

Below is a shot of the almost complete stone planter. You can tell we’re no pros by the amount of mortar mess happening in that picture.

Some cleaning was definitely in order. I checked in with a couple pros, and they use muriatic acid to clean mortar off slate, but we weren’t ready to mess with acid if we didn’t have to. So, when someone suggested white distilled vinegar, we gave it a shot.

We sprayed the vinegar on the stone, let it set for a minute, then scrubbed the mortar off with a wire brush. Luckily, it did the trick (and left the whole place smelling like salad dressing). The following weekend we set the bench caps, which was easy with the exception of those darn 45 degree corners again.

In order to get the mitered look we were going for, we measured the distance at the front and back of the cinder block to the corner, then transferred those measurements on to the stone. Once we got the first angle correct (there were a couple mishaps before we nailed the process down) we flipped the stone over and traced that line on the second stone, so the two would fit together properly.
With the hard work done of measuring and cutting the stone, we mixed up another couple bags of mortar, and laid it on top of the cinder blocks. Here’s Ryan smoothing it out before placing the stones. And here’s a shot of the bench complete. You can see in the picture below the corner that I was talking about. It’s got a nice clean mitered look. And here’s a different angle. I planted different varieties of lettuces in the box on the left side of the house, and I can’t wait to make lots of summer salads with it (that is if the pests don’t get to it first). And here’s the second box. I planted the tomatoes about a month ago, and they’ve really taken off! It’s so fun to watch plants grow! And here’s a before and after for you! The stone facing really makes the bench look expensive. It’s one of those projects that makes me back up and say wow! I can’t believe we made that from scratch! We’re really happy with them and looking forward to lots of years of planting and growing tomatoes and peppers. Check out the one coming in below.