This is the deal... sand adds strength and it will last double the length of time over those made with just sphagnum peat Moss, vermiculite, or perlite, or even coir (coconut coir - the stuffing type stuff, string like, not the potting mix type). I have had sand ones last 20-30 years sitting outside. Note - I used a penetrating (not a film) sealer on mine (in any cement) to prevent freezing and thawing - you spray after final uncovering before letting them sit for 6-8 months outside. After the soaking, I will spray again, let dry a few days before putting soil in. They need to sit outside to stay damp. All of those items do well but they breakdown over time causing weakness and the more porous, the more vigorous roots can get in the crevices, push through, and cause it to eventually crumble. I have used the perlite, peat Moss, portland cement and if properly cured (cover with heavy plastic until time to unmold, then keeping for 1-2 weeks staying damp (daily misting) under plastic in the shade, then uncovering, putting in the shade and spraying 1-2x daily if the temps are above 85-90+F, just 1x day if under that, let them cure and strengthen for 6-8 months outside before doing a 3 day soak changing the water daily) before using. The soak and daily change is to get rid of the excess lime. Use a pH meter (cheap) or test strips and keep changing until the water gets down around 7-8 or let sit outside for another 4-6 months — you can decorate with them around your porch or only plant something really alkaline loving. But it’s best for long life not to plant in them for the first 6-8 months just staying damp and in the shade. Most plants like 5.5-6.5, a few like snaps, beans, asparagus, alpines, carnations, lilacs, etc like 6.5-7.5. Nothing likes over 8 and it will leach into the potting mix. Your potting mixes will be initially charged with lime to be 5.5-6.5 depending on the manufacturer but that leaches out in about 6-8+ months if outside. Concrete or cement has a pH of 12-13 and will leach into the potting mix or into the water of a bird bath. That is highly corrosive and not good for anything, and it will easily eat through paint. I like the ones with peat Moss, perlite etc, don’t get me wrong - because I can make them look older and I always use grey portland - white looks too unnatural. If I have to use white, I use grey concrete dye. If I use sand which it’s been 40 years since I made and sold them... I use also concrete dyes non toxic cause I like it to be grey and brown looking. And maybe use some of the other things like the coir to add texture and also some strength. The coir you can cut up with shears too to make smaller pieces and singe later if peeking out or just let alone. True coconut coir fiber (it’s from between the outer and inner shells.. ..it’s not coco peat) is used to make rugs/sleeping mats, mattress stuffing, ship rigging and ropes or for fishing nets. I don’t know if it would be stronger than the synthetic fibers but it would be natural. Not sure where to get small amounts but from mature coconuts it’s very strong. Read and a picture in the following https://en.m.wikipedia.org/wiki/Coir If you have done 6 months (over the winter is best - it also helps you not to get impatient and use too quickly, make in mid to late summer, go through the steps and have the uncovered time from say Sept-May. But if the pH is still high, and you don’t want to wait anymore time - use artificial plants (some are pretty believable) or plant Lily of the Valley Viper’s Bugloss Anchusa Trifolium (clovers) Polemoniums Wild marjoram Lavender California Poppies

Sean, thank you for the comments. On one day I told my friends that I thought a rhubarb path was what they needed for this area. The voids were dug out with a small trowel and three pronged hand rake. The leaves were within walking distance. The hardest part I think was that I had asked if they had a wheel barrow for mixing, they said yes. But their wheel barrow was one of the taller plastic ones that did not have a flatter sufaced bottom, and the first two bags I mixed together with my hands. The next bags were one at a time. All in all the project really is as easy as the photos. And since it is really that easy it would be very easy to start with and get 'BITTEN' by the bug here. Several years ago I also talked about the sea stars that were in my yard, set a cardboard pattern cut around, scooped out to 1 1/2", put mix in and patted smooth, then wiggled rocks in, and watered the area. A great project with kids. Sean are you using your silicone mold as a texture pad or how are you using it? I have as I said in another thread not taken the extra step of making a POP mold. Waiting anxiously to see the project you are doing. Dena

Wow, that is a pretty ambitious 1st project and you pulled it off beautifully! I like the rough text you created with the steel wool - it makes it look more like lava rock/natural stone. Very nice job! I have not tried a lantern yet myself, but some others that have posted instructions make "negative" space molds for the openings in the legs and the windows with styrofoam - that might save you a bit of carving next time. Then you can just do some clean up carving to make it look less cast and more carved - like this peice does already. Good work - I can't wait to see more!

Maybe tasting the water wasn't such a good idea. I drained the water off and left the shells sitting in a stainless steel bowl for a couple days. Well today when I was getting ready to use them they smelled very GAMMY. I assume there is still very tiny fragments of meat attached and in the damp conditions they started to decompose. From now on I will drain my washed shells pronto. Just finished a Crete square little bowl using Perlite and the shells as my aggregate. The shell fragments are all less than 1/4 of an inch. Looks kinda cool, I just added a pinch of blue pigment to the white portland. I can hardly wait to see what a stiff brushing will do to remove the Portland haze. I'm hoping that pearly glisten of the shells is visible. It will be interesting how it feels to the touch. Very hard on gloves BTW.