I would spray it and keep it in a plastic bag or covering. It will cure to fast if you don't. Not sure but if it cures too fast it wil be more likely to crack.

Well I put a cardboard over top, I guess I'll spray it again tomorrow with a light mist. I never did understand chemically how and why concrete needs to cure like that.

I also don't like the fact that I read one should cure a tufa item for over a month (even longer). Seems like an awefully long time before you can use or even examine closely what you've made.

I'm quite afraid I'm going to end up with junk here on my first try, but you got to start out somewhere.

The curing process has to do with the strength of the finished peice. I don't know that I have ever timed the waiting time to use. I know it is the lime that is in the pot that most plants don't like. I have never done a water bath. Normanally I make pots and use them when I need them. Let us know how it works out. I ususally try to check often when I post but sometimes it is a week before I check in to see what is going on.

There are many formulas and opinions for making Hypertufa.

As ladycraft said curing increases strength. Water and cement have a chemical reaction when combined in the right amounts. This process is called "hydration" and causes cement to harden when combined with water under the correct temperature. Very hot outdoor temperatures can cause too much water to evaporate too quickly, while temperatures under 50 degrees Fahrenheit can slow curing precipitously.
So the most strength in gained in the first week. If you can keep it moist for another week, it will gain a little more strength but not as much as in the first week. A third week is good but not really that much more strength.
So keep it very moist for 1 week, maybe 2.
Wrap in a plastic garbage bag, hose it down daily if needed. Just dont let it dry. Covering with cardboard on a hot day may not seal the moisture.

Well I took a look, and my pot looks more like peatmoss & perlite than it does concrete. I guess I should have put more concrete in the mix, or maybe I'm just paranoid.

But I have the feeling if I take it out the mold now it's going to crumble into soil. Good thing I didn't make a huge water-fall as my first hypertufa project!

Here is my Simple fomula for Hypertufa

1 part portland, 1 part perlite, 1 part potting soil ( peat) and add ( usually 1 part water) depending on how damp the potting soil is.

Mix until the consistency of fresh hamburger. Not too wet not too dry.

Spray inside mold with PAM non stick spay. Take mixture and make a small hamburger patty and the allpy to inside ( or outside of mold. Repeat - overlaping .

Cover with plastic bag, remove next day ( usually ) rough up with wire brush, spary with hose and put in bag and seal.

Check daily for 1 week. Hose down if needed.

Tax - you may have had too much peat - and not enough portland

Keep on trying and dont get discouraged.

I live in the northwest in the summer and in the southwest during the winter. The only time I'm concerned with my projects curing too fast, is when I'm in the desert. I've never had a problem in areas with a bit more humidity. I've never misted or covered, and most of my projects can be used within the week. If you had to wait a month, most of us would be too impatient and probably never do hypertufa. Even in the desert, the cracking problem occurs more in the large projects, like birdbaths or bowls. In the smaller projects, I've never had a problem. Hope this helps, and no, you don't have to wait a month to enjoy your hypertufa.

Remember, equal parts of perlite, portland cement, and peat moss. For projects that I don't intend to hold water, I've even used one less part of portland cement, and they come out fine.

Hmm, I did some hunting around and most of the recipies I saw, including instructions from a book said 1 part moss, to 1 part perlite, to only 2/3 of cement.

I guess to be more on the safe-side I'll go all even parts in the future. I guess lesson learned.

The only time I saw recepies for all even parts, was when perlite was changed to sand.

Hypertufa formulas can vary and still work, what ever works for your is the one you should use.
Back to your original post, water and moisture is the key factor to success. Keep it wet for one week. Seal it up tight. A little more or less Portland will not make much difference. Also your mix should be damp and completely mixed together --- damp like raw hamburger,. If it is too dry or too wet it may impact the success of you project.
trial and error will be your best teacher.

Have fun --- Mike

Here is a link that might be useful: Blog

Plantman is right. It's more about the moisture than about the amount of portland cement. I've had very good luck with recipes of equal amounts of perlite and peat moss with one less part of portland cement. I use equal parts if I make large leaves (for extra strength) and containers that are meant to hold water. And, for those, I use Thompson's water seal until it's water tight. It's kinda whatever works for you. You discover what works best through much trial and error. I always go by "keep it simple". If it was too complicated, I wouldn't be doing it.

As far as making water tight items with hypertufa, and then using Thompson Water seal on them as valolson1 above had commented....I'm wondering what the purpose of the peat moss would be in that item. I thought the peat moss was moreless for plants roots to be able to receive oxygen and to also hold water. When ever I make something that I want to be stronger, I usually leave out the Peat and add more Perlite, or Vermiculite. I'm very new at all this, and was just wondering your all thoughts.
Thanks
Judy

I beleive strenght is accomplished by proper curing,
concrete which is very strong has a variety of ingedients. My opinion- increasing portland will not give you as much strength as alowing the hypertufa to slowly cure, keeping it wet the entire time. Deleteing peatmoss from the ingiedient list may help with water retention. If I need to make a bird bath, I use portland and sand ( 1-3pts)

Some other steps to increase water repel ability. Pack you mix into the mold - firmer , less air spaces.

Use an admix ( bonding agent ) in place of some of the water.

Use a penetrating sealer, I beleive Thompsons is a surface sealer.

There is no wrong answer here -- just lots of good ideas.
If you are new to this , seach this forum, see below.
Lots of good ideas.

Mike

Here is a link that might be useful: Seach on Sealing concrete....

I have several birdbaths that I made over five years ago. The one pictured in the foreground of my photo is about seven years old. It gradually collects moss and it's been tipped over a time or two by a grandson and dogs. It still holds water and it was made by using equal parts of portland, perlite and peat moss. For waterproofing, I just sealed it with Thompson's Water Sealer. I'm not sure if it's a surface or penetrating sealer, but it has worked for me.

About peat moss...interestingly enough, I think the peat moss adds strength by naturally eroding away over time. If you touch a hypertufa project years later, it almost feels like a rock, even tho the peat moss in it is probably long gone. All I know, is that most projects I've made are still serving a purpose years later and I never misted or covered my projects in plastic.

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