Abies balsamea 'Nana'

Abies balsamea 'Nana'

Monday, August 1, 2016

The making of a mist system

Last week I spent a few days in the North Cascades. It was a wonderful trip (hike photos to follow) and was well-timed in the sense that I had begun to develop a bit of cabin fever. I needed to get away. Unfortunately, it wasn't the best timing weather-wise. As summer made an untimely return, I fretted over leaving my plants for 4 days.

Part of the mist system in its first incarnation, held up with duct tape, naturally.
In addition to some other preparations, I set up a small irrigation system with fogger heads to raise the humidity and lower the temperature in the greenhouse. A hose timer allowed me to schedule a healthy dose of misting every six hours. It was enough to keep my plants from drying out, though the flowers of one vireya were a bit wilted on our return. The foliage of the plant had prevented sufficient water from reaching the roots, but the flowers perked back up and the plant is no worse for wear. Why didn't I set up a drip system to water each pot? Mostly laziness, but also a lack of time and materials. The drip emitters didn't work well on the same system as the foggers, and I didn't have a second timer to put the drip emitters on their own system. So I just watered everything well before we left and let the foggers do their thing. It worked rather well.

Anyway, we're back and I no longer need the mist system as it was (though some of the plants in there would probably still appreciate it). I decided to redesign the mist system to work as a propagation mister.

The fog emitters fit on the ends of the 1/4" plastic tubing standard to most drip systems. Technically, I should have used an adapter, as the fog emitters have threaded ends. We have them, but that would have involved a tiny bit more cutting and attaching and I've already said I'm lazy. They fit well enough straight into the tubing.


This is the hose-end assembly, including the timer. Below the timer is a filter, which we need with our iron-heavy water. Below that is a metal adapter we had to use between the filter and the pressure regulator below that, because of course they had different threading. Can't make things too easy, can we?

For the vacation set-up, I had the assembly hooked up to the end of the green hose and set up on the bench, but now that it's taking on a more permanent role, I added a Y to the faucet to allow use of the hose while the mister does its thing.


Of course, as I write this and look at the photos I took, I'm realizing they really aren't detailed enough. But assembling everything really just involves a sharp pair of scissors or a knife to cut the tubing, and then you just shove the connectors into the tubing. There are "T" connectors that allow you to add branches to the line, or emitters. For the foggers, I simply cut the tubing where I wanted to place an emitter, added a "T," cut a short piece of tubing to connect to the that, and put the emitter on the other end of the short piece. It's so simple, even I can figure it out!

The start of the new propagation area. I used duct tape to hold the hose up again. I'm just classy that way. Since these foggers produce a somewhat narrow spray, I added these two oriented horizontally at the back to give a little more coverage.


The tubing fit perfectly into this channel in the wall of the greenhouse, so I ran the tubing up along that just to make things look a little tidier.


The "finished" system, at least until I start tweaking it. There are five emitters in total. Supposedly, each emitter covers an area 2 feet in diameter, but I found the cone to be narrower than that at the distance from the emitter to the bench below. If I could put the emitters and the bench further away from each other, perhaps it would work better.


And that's really it. I am considering setting up a removable curtain enclosure for extra humidity on those hot days when I need to keep the greenhouse door open. Something involving either strong clips or magnets glued to the aluminum greenhouse frame.

The final step, and this is really the most important one, is to immediately fill your propagation area with cuttings. I started with Salvia officinalis 'Berggarten'. I like to remove all but two or three mature leaves. In addition to reducing transpiration from the stem, this improves air flow when the cuttings are put in a pot together and reduces the risk of disease.


Usually I prefer to use perlite for rooting, but I had a good-quality soilless potting mix on hand that should work well enough. My preference for perlite is that the more open material allows better drainage and decreases the risk of rot. I use a liquid rooting hormone you should be able to find at any well-stocked garden center. I found mine at Portland Nursery on Division. The liquid hormone works better than the powder form that's more widely available. You can also adjust the solution for the type of cutting, weaker for plants that root easily and stronger for plants that are difficult to root. You can use a wooden chopstick or skewer to make holes for the cuttings in your medium, or not. It is useful if you have soft stems and an abrasive medium, but the salvia stems were pretty sturdy so I quickly abandoned the skewer and simply stuck the cuttings in the soil.


Be careful of putting too many cuttings in one pot. Pack them too tightly and you'll restrict airflow, increasing the risk of mold developing in the center and wiping out most, if not all, of your cuttings.


A little fast-forward magic and the new propagation area is almost full! In addition to the 'Berggarten' sage, I took cuttings from Salvia officinalis 'Purpurascens', Santolina chamaecyparissus 'Lemon Queen', Geranium harveyi, a cultivar of Lavandula stoechas the label of which I've embarrassingly misplaced, and three selections of Zauschneria: 'Wayne's Silver', 'Catalina', and 'OC Hybrid'. There are a few more plants slated for the chopping block. I'm hoping to have these ready for planting in October.


Which reminds me, here's the latest on that big area I'm preparing to plant in Fall. My dad helped me expand the area a bit to encompass the Cotinus 'Grace'. After all, why mow around that one little bed when you can just eliminate the need altogether? If you don't remember what it looked like before, here's the original post. I also removed the sickly ginkgo. It pained me to cut it down, but if a tree is still struggling after almost 10 years, it's obviously not in the right location. Hopefully the Arctostaphylos glauca I've picked out to plant nearby will be better able to handle the extremely dry clay soil. All the cuttings I've got in the photo above are destined for this area.

This area is now too wide for me to take a normal photo of it. It made me try out the panorama feature on my phone camera! It's a little hard to see the line because the grass has become almost as brown as the soil.
There's one additional step I had to take post-completion. Realize that your timer has a minimum interval setting of 6 hours (much too long for cuttings to go without mist) and promptly search online for a propagation timer/mist timer that allows intervals down to at least minutes if not seconds. I don't think I'll really need intervals of less than a minute, but who knows?

12 comments:

  1. Your mister system is pretty impressive, duct tape and all. Thanks for the comments on the rooting hormone - I use a liquid form (on the few occasions I actually take cuttings) but I'd been wondering if I should switch to the powder form.

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    1. Thanks, Kris. I used the powder form for a long time with pretty good results, but I've definitely seen improvements using the liquid hormone.

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  2. You make it all sound very easy! I keep thinking that it would be great to have emitters for watering my own greenhouse and the many containers all over the garden but have been intimidated by the unknown process. Your post has inspired me to do a bit of research. Your mist system is brilliant!

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    1. The hardest part is designing the system, but it's also a fun challenge. Actual assembly is a snap. Looking forward to seeing what you come up with!

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  3. Looks complicated. I'm usually envious of all the greenhouse owners. Not so much today :-D
    Exciting to see the rooting trays, especially the sages, which I'm a huge fan of. The new bed will look great with mass planting from these trays.

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    1. It really is a small, simple system. The cuttings are still looking good today, despite not being able to mist them frequently enough. Thankfully it's cool. Hope I get lots of plants out of those cuttings!

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  4. The wonders of the scientific mind...makes me think of a line from Dylan Thomas "easy...for Leonardo".

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    1. Oh dear. Now that IS overstating it. I wouldn't dream of comparing myself to da Vinci.

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  5. After several years of putting up the shade pavilion greenhouse each autumn we're still using duct tape to connect the plastic panels together. It's good stuff! (of course we have stepped up to the removable/replaceable non residue leaving kind).

    Nice work and I'm happy to see the area already full. It won't have that real propagation table vibe though until you've got the shower curtain in place and it has that attractive green tint to it. Oh and I'm not being sarcastic, I really do love that green tint!

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    1. The wonders of duct tape! Ha! I'm going to try to avoid the slimy green curtains. You might have enjoyed the look, but working around those things always set off my OCD.

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  6. Do you find that wet duct tape sometimes loses its grip? May I suggest binder clips from the office supply? They come in several sizes. I use them in the greenhouse for things like hanging a plastic tablecloth as shade on the west end and holding various things.

    My permanent mist system uses 3 metal heads and copper pipe at the west end of the greenhouse so the vent fan on the east end pulls air across where the mist is falling. It helps to cool the air a bit. Instead of trying to move the mist to the plants, I move the plants where they get the most benefit.

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    1. I did notice some slippage on the original design when I came back from vacation. So far, the tape on the current incarnation has maintained a firm grip. But thanks for the suggestion of the binder clips! If the tape does start coming off, I'll try those! And I think I'll use them to hold up a shower curtain around the cutting area for added humidity, though I haven't needed that yet.

      Yes, I selected the most convenient spot in the greenhouse to set up the mist system for cuttings, and moved the plants there. It's so nice learning the microclimates of your greenhouse so you can give your plants the best possible spot.

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Thanks so much for taking the time to leave a comment! I love hearing what readers think and answering questions. I also welcome suggestions for improvement!