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How often to water cuttings in pure Perlite?

Posted by love_the_yard z9A Jax FL (My Page) on
Mon, Jun 3, 13 at 11:50

How often do you water cuttings rooting in pure Perlite with a humidity bag? Perlite is not like other potting mixes where you can poke in a finger and feel the dampness. It's a closed system (rooting cup and bag), so theoretically, moisture should not be lost. However, if some cuttings take 4-6 weeks to root, I wonder if careful watering to re-wet the Perlite should be done?

Carol in Jacksonville

Follow-Up Postings:

RE: How often to water cuttings in pure Perlite?

It depends :-).

Actually, you can sorta poke your finger around and feel the dampness. Another trick it try to stir the top inch with a pencil - if thats easy to do, then its drying out.

Here, its very arid, single digit humidities, and I have to add a bit of water every week or so.

I try to keep the container the cuttings and perlite - which has drain holes - in another water tight container, and if that has 1/4 to 1/2 inch of water, then I know the perlite is moist enough. There is some capillary action between the perlite in the container and that of the dish, which keeps at least the lower part of the container moist.

If the water in the container has evaporated, then I add water until it runs out the bottom again.

Another way to tell is by weight. Water it, lift it up, and you'll get a sense of how much damp perlite weighs.

As well, the larger the container and volume of perlite, the easier it is to manage the moisture level. I use pots that measure 5 " x 5" x 5" deep. Its much more difficult to do in smaller containers.

RE: How often to water cuttings in pure Perlite?

David, those were all GREAT tips! Thank you so much!


RE: How often to water cuttings in pure Perlite?

David, I had mine sitting in a dish of maybe 1/4" of water. When I checked on my cuttings, some of them had white fuzzy mold and were rotting! Too much humidity! We are are at 96% humidity right now, so I removed all the domes and the bags. I threw out all of the damaged cuttings. Even some of my little stakes were moldy - now that is crazy. I did rewater the perlite and there are good drain holes, but I removed the water in the drainage dish. I hope the rest of them make it. Hibiscus cuttings.


RE: How often to water cuttings in pure Perlite?

Thank you David and Carol for this thread. I've had exactly the same question. I tried propagating lavender and two kinds of salvia in perlite. After about 10 days the lavender flopped and even I could see that they were too wet. Then one of the salvia varieties went brown. I think they were also too wet. Now I'm down to the last salvia (salvia greigii) which looks exactly the same as when I put them in the container. I don't know what that means except that the salvia is very tough.

I'll start again with David's hints in mind. I'm in the desert Southwest with very low humidity. Everything feels dry to me.


RE: How often to water cuttings in pure Perlite?

Why are you using pure Perlite? Some fine coir and leaf mulch mixed gains enough moisture from the humidity in the bag. Also the mixture should be microwaved for five minute before use in order kill every thing including mould.
Sorry, I love to grow cactus seeds so I have to be very particular about hygiene

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