DIY: Build Your Own Automated Misting Bed

So you’ve finally gotten that piece of land to start your homestead, you’ve done your site plan and installed your mainframe earthworks. Now its time to plant!

But wait, all of those plants cost money! And not just pocket  change, but some serious dough! If each fruit tree you plant also needs a comfrey, two perennial culinary herbs, a groundcover and a perennial flower you’re looking at a hefty plant bill really fast.

Even small earthworks on small properties have room (especially with a permaculturist’s eye) for hundreds, if not thousands of understory plantings. Groundcovers, herbs, flowers, shrubs, berries, vines – you name it, we can always fit one more plant!

If you’ve looked at retail prices for plants like these it becomes quickly obvious that even to minimally plant a 10′ x 10′ area you could be looking at hundreds of dollars in plant costs.

Thats where the value of propagating your own plants really comes into play.  Its literally like printing money!

In this post I’ll show you how I built one of the key elements in our homestead-scale nursery, the automated misting bed, to allow us to propagate valuable plants by the thousands for planting out a developing farm.

What is an automated misting bed?

An automated misting bed is a raised bed-like structure into which plant cuttings are placed to help them set roots. Its like a really fancy raised bed garden, only it has little overhead misters that come on at a regular interval to keep the tender cuttings moist while they strike roots.

Automatic Misting Bed with shade covering.

How many plant cuttings can I fit into a bed?

It depends on what types of cuttings you are placing into the bed. In my case, I’ve had nearly 800 cuttings in my 32 square foot misting bed when I was propagating pencil thick cuttings of various perennials. Because we’re only helping the cuttings to strike root in this bed and not growing them out, we can pack in cuttings as close to 1″-2″ apart.

As soon as the little cuttings begin to set healthy roots, we can pot them up (or sometimes plant them straight out!) to grow them up to a larger size with a full root system.

What is the rooting media composed of?

In the case of the misting bed pictured below, I put in a center divider to create two 4’x4′ boxes, each 12″ deep to allow for two different types of rooting media. The left side is 50/50 perlite and peat moss, and the right side is 50/50 perlite and sharp sand.

What’s the difference between the two types of media?

(Left Side) Peat moss and perlite is very light and holds moisture very well (i.e. can remain moist longer than the sand side). I have found that it works well with plants that develop fine roots or hairnet style roots. Some things I have propagated that have done very well in this bed include rosemary, sage, salvias, Pakistani mulberry and maypop.

(Right Side) Sand and perlite is a somewhat heavier mix and it drains much quicker than the peat moss mix. It is a great rooting medium for things more susceptible to being damaged due to excess moisture or waterlogging. Some things that have done very well striking roots in sand include grape vines, black locust,  Persian mulberry and vetiver grass.

Peat Moss/Perlite on the left, Sand/Perlite on the right.

Most plants do reasonably well in both types of rooting media, but sometimes there is a marked difference in how well they do in one versus the other. Grape cuttings, of which all of my successful strikes have occurred in the sand/perlite mix, are one example.

Now, onto the automation. The beautiful thing about this set up is that you can have hundreds of cuttings going at one time and you can rest easy knowing they are well taken care of.

For this bed I used press-fit Tornado Misters coupled with a MEAD anti-drip device and a press-fit MEBARB. This ensures that once the misters shut off no water droplets will fall and damage the tender plants below, or create an extra soggy spot in which algae or mold might establish. Each unit looks like this:

Mister set up – MEBARD 1/4″ barb, MEAD anti-drip device and the Tornado Mister – all press-fit together for easy construction and maintenance.

Each sprinkler is fed by 1/4″ black poly tubing that plugs into a 1/2″ black poly main line. The main line runs all the way back to the “brain” of the whole unit – the timer and valve assembly.

 

The “brain” for the above assembly is the Galcon AC-6S 6 Station Greenhouse Timer. This model is not weatherproof, so it will need to be somewhere protected from the elements. NOTE – this is not the same timer as the Galcon AC-6! The AC-6S model has the capability to program cyclical irrigation windows as short as 1 second, which you will want for your misting bed. If you are planning on having more than 6 stations running then you can upgrade to the Galcon AC-12S 12 Station Indoor/Outdoor Irrigation Timer and run up to 12 separate stations.

Galcon AC-6S Greenhouse Irrigation Timer – capable cyclical irrigation in windows as short as 1 second. This is critical for a misting bed!

For the actual manifold assembly you will need a filter, a master valve, a manifold, PVC connecting pieces and however many AC valves you require.

For the filter, I go with the Amiad FAM34200 3/4″ High-Pressure Filter due to its high pressure rating and its capability to be left under pressure indefinitely. Not all filters are built to have constant water pressure, but the Amiad brand is and I’ve had good results with them. I generally go with the finer mesh, but you can make that choice depending on the quality of your water source.

Amiad 3/4″ FAM34200 Filter with 200 mesh. The orange valve on the bottom allows you to flush water through the system as needed, and the entire housing unscrews very easily to allow for more thorough cleaning if necessary.

From the filter the water passes through the Master AC Valve, which is the same as all the rest of the valves you will use, it just comes first in line. This valve will open can close with each irrigation window. This is to take the stress off of the downstream valves so that only the master valve is under constant pressure, not all of the valves in the entire system. It’s much cheaper to replace a single valve than all the valves in your manifold should they fail due to being under constant pressure (which I have never had happen with Galcon valves, but its just a precaution to extend the life of the system and ease future maintenance). For this system I use the 3/4″ Galcon 24 Volt AC Valve, again due to its high pressure rating (we have ridiculous water pressure on the farm).

Galcon 24V AC Valve – the valve pictured is the master valve for the entire system.

For the manifold that connects all of the valves you can either make your own or purchase pre-made manifolds. I prefer the latter option as you will save a lot of time in construction and they are reasonably priced and well built. For this system I purchased one 4 Outlet Manifold and one 2 Outlet Manifold and coupled them together to be able to run 6 valves and thus maximized the capacity of the AC-6S irrigation controller. If you don’t need to set up all 6 valves right away its a good idea to purchase the caps that come with this unit – get at least one for the end!

IMPORTANT NOTE: These single piece manifolds are 1″, and you need to drop down to a 3/4″ AC valve. You will need a part called a Man Nipple to step down the pipe size here. You will need one of these for each valve except the master valve.

For connecting your valves to your timer you will need wire. The question is how many strands? If you want to have 6 valves AND a master valve you will need a minimum of 8 strands of wire! (one for each valve = 6, one for the master valve = 7, one for the common = 8)

You could purchase a 7 strand and a 2 strand, or just get the 13 strand to give yourself room to upgrade to more valves and a more capable timer down the road.

PVC Connections: Given the inevitable situation specific shape and application of these units, I won’t attempt to list quantities and specifications of the various PVC connections you will need here. Easiest way to figure it out is once you have all the items we talked about above, lay them out as you intend to use them. This will give you a good idea of which connections are needed where and in what quantity. And you can always take your valves, filters and manifolds into a plumbing section and put it all together right there on the floor or have someone help you find all the right pieces.

Shopping List

That’s it! Get it built and start printing money for your farm or homestead! Please leave a comment or send me an email if you have any questions and I’ll do my best to assist you!

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