Congratulations Marleah! My mister experience is from the old one years ago at The Huntington Library. Totally different conditions and climate, but, hopefully, an idea of what worked in hotter, more arid conditions might help give you a starting point to begin experimenting.

The set up was a table, about the size of a double bed. It was raised about waist high from the ground and contained a bed of lava rock with a heat cable buried an inch or so under the surface. Bottom heat of roughly 70 F aids in rooting. Higher temps for the bottom heat seem to inhibit root formation.

The misters were set atop 18" pipes, inset from the corners about a foot. There were four, one at each corner. The table was protected on the east side by a lath wall; on the west and north by the lath house itself. The south side was in direct sun and it was open over head. The wind blew through the lath house and over the table freely. There were two timers, one was a one minute timer plugged in to a 24 hr timer. They were set to only mist during daylight hours when the humidity was lower with tremendously greater evaporation than at night. The mist interval was ten seconds every minute during the day light hours.

The planting medium was a 50-50 mix of coarse builders sand and perlite. When night temps were at least 70 F and days were quite warm, MOST roses rooted in roughly 7 - 10 days. The cooler it got, the slower they responded.

A local specialty rose nursery about that time, tried to set up a mister which was enclosed in plastic. They repeatedly attempted using Bandini potting soil under the mist and their roses rotted. This was here in the San Fernando Valley, a bit more arid than San Marino where The Huntington is located, and the heat quite a bit higher than at The Huntington.

The thing to remember is, with a regular mist, the medium is going to remain wet. An organic potting soil stands a good chance of souring with constant moisture. Sand or a sand/perlite mixture will retain quite a bit of moisture while also providing excellent drainage and will never "rot".

Sequoia Nursery ran out door misters, as well as indoors under plastic. They used a fir based, soil less mix with about 50% perlite under their mist. Under plastic, their intervals were set much wider apart. Outdoors in filtered sun, the mist went off more frequently. Their conditions were also quite warm with high evening humidity and relatively lower levels during daylight hours.

I would imagine, you will want to set yours up with an on/off switch so you can conveniently turn it off and on. I would also imagine you wouldn't want it running at night when it is much cooler and wetter. The whole idea is to keep the cuttings moist so they don't dry out until they root. The medium needs to remain moist but not soggy. Very loose, fast draining types like the sand or sand/perlite can be continually watered and still have decent oxygen in them because they have large air spaces between their particles and don't retain vast amounts of water.

If it's cool with high humidity, you may not really need to run the mister unless you see the mix and cuttings drying out. When it's warmer, drier or windier, you may have to run it to maintain the cuttings, preventing them from wilting and their foliage from drying out and falling.

We always found the most suitable material for the mister were recently spent flowering stems. I routinely used the actual end of those stems and found they rooted faster, better than wood further down the cane. It was likely due to the higher concentrations of auxins, hormones and other nutrients in the actual flowering shoots compared to the wood beneath them. Not to mean you shouldn't try anything and everything you have available as most will eventually root. This was just what was the most efficient and successful under the conditions I operated under here.

If you set it up under plastic, you won't have to run it as often, but you also stand greater potential of experiencing rotting, insect and disease issues. Outdoors, particularly in direct sun, and with a very efficiently draining medium, rotting, insects and diseases should be pretty much non existent.

I don't know what temperatures you can expect when your "summer" arrives, but I would imagine your success rate will be at its highest during that period. You'll probably have to experiment a lot to determine where the optimum place is and what intervals you should use for the best results. Perhaps, if Paul Barden (trospero) finds this thread, he could give you better suggestions as I'm sure he's propagated under mist in a climate probably very similar to yours. You might see if he can be messaged through GW and ask for his advice. Good luck! Kim

Thank you Kim so much for the very helpful information!
I appreciate the time you took, and will read thru this tonight :)

Marleah

Kim, I just read your answer to this post I totally enjoyed reading it. Thank you so much for the information you gave.
James

I'm glad you enjoyed it. Hopefully, it gives some ideas which can be massaged to fit other climate types. Good luck! Kim