ML Irrigation / Applications / Propagation Mist and Fog Systems for Cuttings, Plugs and Seedlings
ApplicationA propagation mist system keeps unrooted cuttings, seed plugs and young seedlings from drying out until they have roots. Fine mist or fog goes on in short bursts, many times an hour, to hold a film of water on the leaf and keep humidity high at the bench without soaking the media. The same hardware, run on a different schedule, raises humidity and pulls temperature down across a whole house.
The system is small in flow but unforgiving in detail. Nozzles with orifices this fine need clean water and steady pressure, valves that will open and seal on a zone drawing a few gallons an hour, and a controller that thinks in seconds rather than minutes. This page covers each part in the order you would design it, using the product lines in the ML Irrigation catalog.
Request a quote for this systemCall (864) 862-5000
Start with the water, because the nozzle decides how clean it has to be. A propagation fogger throws droplets measured in tens of microns: Netafim rates the CoolNet Pro at a 65 micron average, and Rivulis rates its Fogger at 55 microns at 60 psi. Orifices that fine plug on grit a drip emitter would pass without noticing.
Every mist nozzle carries a filtration rating, and the finest nozzle on the system sets the filter for the whole system. Rivulis calls for 120 mesh on the Fogger and Super Fogger, 100 mesh on Green Mist and 80 mesh on the Rondo Mist Sprayer. Check the rating before you order the filter.
The source matters as much as the mesh number. Well water usually needs a screen or disc filter sized for sand. Pond and surface water carry algae and organic matter that mat a screen quickly; grooved disc filtration holds that material far better, and an automatic unit like the Amiad Spin Klin Compact Angle 2 inch is sized for a single greenhouse or propagation house at up to 66 gpm, with disc grades from 20 to 400 micron. On a system that fires dozens of times a day, a filter that has to be opened by hand becomes the job nobody does. The filtration range covers both.
Opaque white tubing such as Netafim Bright White Polyethylene (PE) Tubing resists algae inside the line and runs cooler than black under glass, which is why it is the usual bench lateral. And if fertilizer or chlorine is injected through the same header, put the filter downstream of the injection point so precipitate is caught before the nozzles.
Mist nozzles are sold for a pressure window, narrower than most growers expect. Bench misters and low-pressure foggers sit in the 30 to 50 psi band: Senninger misters and foggers, Rivulis Green Mist, and Netafim CoolNet Pro and VibroNet at a 30 psi average. The fine-droplet foggers want more. The Rivulis Fogger makes its 55 micron droplet at 60 psi, and the Super Fogger comes in 40 psi medium-pressure and 60 psi high-pressure builds. Below the window a nozzle dribbles large drops; above it the pattern breaks up and fittings weep.
So keep one pressure family per zone and regulate every zone. The Netafim Series 80 Nylon pressure reducing valve is built for greenhouse and mist service, with three spring ranges covering 7 to 90 psi. Check the lateral too: Bright White PE is rated 44 to 66 psi by size, so a 60 psi fogger zone belongs on PVC or heavier pipe rather than thin bench tubing.
The zone valve is the part most often got wrong. A propagation zone may draw only a few gallons a minute, and a conventional diaphragm valve needs a minimum flow to seat; below it the valve chatters or hangs open. Use a low-flow solenoid valve: the Superior SPVLF has no minimum flow requirement, and the 3/4 inch Netafim Series 80 Nylon 2-Way Electric opens at a hundredth of a gallon a minute.
Fit anti-drain devices so laterals stay full between bursts. The Rivulis Super LPD holds the line pressurized and closes at 9, 22 or 35 psi by build; CoolNet Pro carries its own low-pressure check valve. Without them every cycle opens with drainage onto the trays below.
Droplet size decides what lands on the crop. A mister throws a droplet large enough to fall and wet the leaf and media surface; a fogger throws one small enough to hang in the air and raise humidity while foliage stays close to dry. Rivulis puts numbers on both ends: the Rondo Mist Sprayer at 150 microns, the Fogger at 55.
For cuttings and seed that root or germinate under a wet leaf, use a mister. The Rondo Mist Sprayer is the Rivulis germination and cutting nozzle: a 6.5 ft wetting pattern at 12.4 or 16.1 gph. Green Mist is their bench nozzle, mounted 3 to 4 ft above the bench with heads no more than 2.5 ft apart on laterals 3 ft apart. Netafim's VibroNet covers 4 to 5 ft benches on 3 ft spacing, with a blue nozzle for lighter mist than the 9.2 gph green. Senninger misters come upright for benches and inverted for drop assemblies over trays.
Where you want saturated air rather than wet media, or humidity and cooling across a bay, use a fogger. Netafim calls CoolNet Pro its best propagation nozzle for that reason, in 1.5 to 3.7 gph singles and an 8.1 gph four-nozzle head. For cooling and humidifying, the Rivulis Fogger is laid out four on a cross or two on a T, heads 6 to 10 ft apart. Senninger foggers are built for consistent start-up on short cycles, and Dramm's JetFog and Misty Mist nozzles thread into rigid pipe or push onto tube.
Browse the misters and foggers range, and hang one lateral first: run it, watch the pattern at bench height, then copy the spacing that works.
A landscape timer runs in minutes; a mist bench runs in seconds. A typical propagation cycle is a burst of a few seconds every few minutes through the day, changing with light and as roots form, and a controller that cannot express that cannot run the bench. Look for a seconds time base and an independent interval on every station.
Dramm's MistTime is the purpose-built box: ten outputs, each on its own cycle with a duration from 1 second to 60 minutes and an interval from 1 minute to 12 hours, run continuously, between set times, or when temperature passes a set point, so the same unit can run cooling fog. It can also turn its last output into a pump pre-start so the system is at pressure before a valve opens. The MicroGrow Water Max gives twelve stations, each usable for mist or irrigation, with propagation mist on its own start, stop and cycle times and a separate night setting. Superior's Sterling Series suits a panel that also runs the rest of the nursery: station times from 1 second to 24 minutes, repeating cycles, and a pause between stations so one valve closes before the next opens.
Where the crop justifies it, MicroGrow's Water Pro VPD replaces the clock with a sensor that reads air temperature, humidity and a simulated leaf temperature, and opens the valve on vapor pressure deficit. Programs step as the root system develops, and night watering can be disabled.
See the controllers range, then request a quote with your bench count, house size and water source, or ask us which controller and valve family fits your benches.
20 of the lines that go into this kind of system, from the categories linked below. Each category page lists every model we carry.
Misters & Foggers·AC Solenoid Valves·AC Irrigation Controllers·Filtration·Pressure Reducing Valves·Poly Tubing
Misters put a droplet on the leaf and wet the media surface, which is how most cuttings and seed flats are propagated. Foggers make a droplet fine enough to hang in the air, raising humidity while foliage stays nearly dry, which suits crops that rot under leaf wetness and doubles as cooling. Many houses run both: fog for humidity, mist on the benches that need it.
It depends on the nozzle. Bench misters and low-pressure foggers in our range run around 30 to 50 psi; fine-droplet foggers run at 60 psi and above. Filtration ratings run from 80 to 150 mesh depending on the nozzle, and the finest nozzle sets the filter for the system. Surface water with algae is better handled by disc filtration than by a screen.
Most diaphragm valves need a minimum flow to close properly, and a mist zone drawing a few gallons a minute may not reach it, so the valve hunts or never seats. Fit a valve rated for low flow, such as the Superior SPVLF, which has no minimum flow requirement, or the 3/4 inch Netafim Series 80 Nylon 2-Way Electric, which opens at a hundredth of a gallon a minute.
Only if it has a seconds time base and a repeat interval on the station. Most landscape timers count in minutes, which is far too long for cuttings. Controllers such as the Dramm MistTime, MicroGrow Water Max and Superior Sterling Series are built with seconds-long run times and minute-long intervals, and the MistTime can also start a pump ahead of the valve.
Planning a propagation mist and fog systems for cuttings, plugs and seedlings system? Send the crop, water source, pressure or pump size and the number of pots, benches or acres, and we'll come back with a material list and wholesale pricing within one business day.
