How old is it - a month yet? How did you cure it, wet or dry? How much water did you use?

My first guess without knowing anything more is that might have used too much water and are having evaporation cracks. On the other hand, if you used too little water and didn't damp or wet cure it for the first week, it may not have hydrated sufficiently. I'm just guessing here.

My mixture was thick, could just barely squeeze out a drop of water. I made it five months ago, kept it moist and covered in plastic for 3 weeks. Then dried indoors slowly at room temp. Here's a picture of one of the cracks. Seems to go all the way through the side and gets smaller as it goes down toward the base.

Here is a link that might be useful: {{gwi:71246}}

Hi Kim,

I'm no expert but since you've ruled out freezing or too wet of a mixture that most likely leaves not enough moisture. Did you let the mixture set for 15 min or so before making the trough? Peat can suck up a lot of moisture and take it's time doing it.

I had a bucket setting outside with some peat moss. After getting 3" of rain last week I tipped the bucket to drain off the water and was surprised to see some still dry peat moss come flowing out.

I find that when using a mixture with peat it's good to make the initial mixture a little bit wetter cuz after it sets the peat will absorb the excess water.

I haven't made anything with your exact mix (I always add at least a little sand for strength) but have had several pots with similar cracks. Mostly on pots where I used sand as the mold and didn't spray it with water right before applying the 'tufa mix.
Jan

Did you make it inside your house? 5 months ago would be in Feb. My experience is that it is best to make Hyoertufa when the temps are around 45-50 degrees. I tied once in the winter in my unheated garage and got the same results- Cracks. Try making anohter trough today using the same steps. Just do it in the shade!Mike

I made several troughs last winter in my heated garage (about 60 degrees), then moved them indoors (about 70 degrees) for curing. One thing I haven't done is let the mixture sit for 15 minutes before forming the trough. I've never been sure how much time I have after mixing in water, before the chemical reaction starts. So I'm always rushing to get it formed.
I stopped adding sand because I was trying for a very light-weight trough, but maybe next time I'll add a little.