Recirculating Irrigation for Living Walls
Recirculating living walls are the best solution for areas without water source or drainage
A living wall recirculating system lets you install a living wall in a place where you do not have access to a drain and water source. It’s also a great way to conserve water too.
A recirculating system consists of 5 major elements, a water tank to store water, a pump to recirculate the water, control system for timing and/or moisture sensing, tubing to distribute water to the top of the living wall, and a drain tray to collect moisture and return it to the tank.
Using a tank at the base is the simplest way to design the system. Tanks can be made from various materials including stainless steel, plastic, or glass aquarium tanks. Beware of materials that will decay such as steel. Or materials that are toxic to plants such as aluminum and galvanized metal. For example, a low cost tank solution can be made from a wood box with EDPM Pond Liner to create the waterproof containment.
Decorative Water Vessel
Secretly store your water in a nearby vessel. The brown jug in the photo is holding water for this clever recirculating system. A drain tray at the base of the living wall collects the extra runoff water. A pump in the vessel connected to a tube recirculates the water to the top of the living wall. A timer controls the pump to keep the living wall properly irrigated. Just add water to the vessel every couple of weeks as needed.
We recommend the Jebao free-floating rotor water pump because it very simple and reliable. It can also survive for a short time when when the tank runs dry. We have these available.
Pump Head or Pumping Height
Make sure your pump has adequate pumping height. Pump head is the height that the pump will no longer deliver water. So you’ll need to make sure you have it rated with a couple of extra feet.
Locate the grounded outdoor digital timer near the wall so you can use the single cord connection directly from the pump. Most Jebao submersible pumps are supplied with a long 16 foot cord so you can avoid having to make connections in wet areas. Outdoor timers typically have closable covers to protect them from weather. If located in a public area you may need to provide a lock box or place in a utility closet nearby.
Setting the Timer
For most situations in bright light the timer should be set to operate once a day for 30 minutes. Indoor plants with lower light will need more time to dry out so plan on operating the system every 4 days for 1 hour.
Observe your plants and make adjustments as required. If you are not sure how long to set the timer, leave the wall unplugged and wait until the soil becomes almost dry and the plants begin to slight droop. Then plug it back in for a good long soak. Make note of days that have past, then set the timer accordingly. Check in often at first to get it right. Close and frequent observation at the beginning can prevent errors. When your watering timing and frequency is correct, your plant wall should be ready to grow and flourish.
Irrigation Tubing for Recirculating Systems
5/8 inch I.D. (Inside Dimension) irrigation tubing is a thin walled tubing that is very affordable and easy to work with. Also it comes in black that prevents growth inside the tube.
Tips and Tricks
If you’re making a larger wall taller than 12 feet or wider than 12 feet consider using 3/4 inch I.D. tubing to get adequate flow. For walls wider than 12 feet using more than one pump is recommended.
Never Use the Drip Line for Recirculating Systems
Drip line has tiny holes that will quickly clog when attempting to recirculate water. Only use drip tubing when using a fresh water supply with a fine wire mesh filter.
Make Holes in the Tubing
Open holes are required to have a reliable working recirculating system. Unrestricted water flow is key.
With thin walled irrigation tubing you can easily melt holes. Melting holes creates even holes with smooth edges to prevent clogging. Use a 3/8 inch soldering iron to melt holes in standard 5/8 inch irrigation tubing. Use gloves so you do not accidentally burn yourself. Also be careful not to burn other items when setting it down. Melting plastic will make a lot of smoke so plan to do it outside or in a well ventilated room. Have a thick terry cloth towel ready to quickly wipe the melted plastic off of the soldering iron. This will minimize smoke and burnt plastic odors.
For Pocket Panels Make Two Holes Per Pocket
Holes should be located at the edges of each pocket. It is important not to flood the top plant with each watering. So position the holes where the water will flow in the slight opening to the side of the wrapped plant inside the pocket. Typically this is about 1-1/2 inches from the stapled pocket connection. You’ll find it much easier to mark and melt the holes facing toward the front. But once your holes are melted then you’ll want to rotate the tubing downward and directly into the pockets.
For Pro System – One Hole Per Pocket
Pro System will work perfectly with one hole per pocket. Use 3/8 inch holes. The tube should be placed at the top and angled toward the back and slightly downward. Standard 5/8 inch black irrigation tubing is used for this large living wall installation to insure adequate water flow. For Pro System attach the tubing to the front of the living wall so it is easily accessible for change-out or modification.
Black Zip Ties
Use zip ties to connect the tubing across the top to the Florafelt panels. You’ll be able to slip the zip ties behind the edges of each pocket and under the staple connectors toward the top. Use as many zip ties as you need to secure the tubing in place. Attach the tubing loosely since you will later need to rotate the tubing 90 degrees downward after the holes are created.
Make the Top Tube Level
Use a level to check that the top of the wall is level.
Distribute Water with Multiple Supply Tubes
Water should travel horizontally no more than one panel or 32 inch of length from a single vertical supply tube. It’s ok to split the tube with a Tee adapter to supply two panels, 64 inch wide, side by side. You may also extend a bit beyond to supply a single extra pocket. But if you add additional width beyond max 44″ per side, you may lose adequate flow.
To adequately supply a larger wall, plan multiple vertical supply tubes between the panels. You may use a single pump but use a tee adapter at the bottom near the pump to create the split. Splitting near the source allows for a more distributed flow through more tubing.
Trial and Error
Test and be willing to make modifications prior to planting your wall. You may determine that you will need larger tubing or smaller holes to get even flow. Therefore it’s best to plan on a slightly larger pump and use larger tubing the first time around. Try to avoid smaller holes as they will tend to clog more quickly.
You’ll need to use good adapters to make a watertight seal between the pump and tubing, also to split the tubing or close the ends. We find the barbed adapters to have the best seal.
Jebao pumps come with adapters that work well with irrigation tubing and there are excellent adapters that are made for irrigation tubing. Jebao pumps have either a 1/2 inch or 3/4 inch female pipe threads on the pump unit which is standard with most pumps.
3/4 Inch Hose Thread Adapter
We like to convert the pump output from pipe thread to hose thread. 3/4 male hose threads are what you normally see on outdoor garden spigots. This lets you easily connect a standard hose to the pump so you can quickly drain the tank.
Irrigation Tubing Adapter
With the standard 3/4 inch hose thread in place you’ll can easily find an irrigation tubing adapter.
Tees are used at the top to split the water in two directions. It’s best to direct the water up the center of the wall so it will evenly flow out each side.
End caps make a nice neat end. But you can also fold the tubing and use zip ties to seal the ends.
Some systems set above the tank so the water can drip directly into the tank therefore a gutter is not required. In other situations you may need to have a gutter to collect the water from the bottom of the wall then direct it to a nearby tank. Gutters can be made affordably with low cost DIY gutter systems available at most box stores.
Test the System Before You Plant
With all the tubing in place and pump connected, add water to your tank. Then plug in the pump and observe the flow of water at the top. Be prepared to quickly unplug the pump if water shoots outward.
Water should gently flow from each hole into the pockets and soon each pocket will become wet at its back and bottom fold. Then water will drip from the bottom panels making a lovely water fountain sound as it reenters the tank.
It crucial to have even flow across the top of the system so all the plants will receive even water. To do this, use a level as shown below.
Create a schedule to keep on top of filling tanks. You can also set the timer for a time you will be at home so you can hear when the water level is low and the pumps are drawing air, making an odd sucking sound.
Top Off Tanks
Add water weekly to keep the tanks full. Use fresh clean water from the tap.
Do Not Overfill Tanks – Wait for dripping to stop
Do not add water while the system is running. Wait 3 to 4 hours for all dripping to stop. Be careful not to overfill the tank. Make absolutely sure water has stopped dripping from the panels before adding more. Water accumulates in the wall then will continue to fill the tanks and cause them to overflow.
Evaporation and water used from the plants will begin to create highly concentrated water with either hard water deposits, the chemicals to offset them, or fertilizer salts. Therefore, you will need to change out the water 3 or 4 times a year. It’s easiest to use the pump inside the tank to do your work. If you used a hose adapter you can easily connect a hose and direct it to a nearby drain. Position the front intake of the pump face downward at the bottom and you can get almost all the water out at once. Removing all the water is not necessary. When the pump sucks air, stop the pump then reconnect the recirculating system. Then refill the tank with clean water.
Hard or Base pH Water Sources
Some municipal water utilities deliver water with a base pH or some well water is very hard. These types of sources will cause mineral buildup in the felt. Or create an extremely base pH that will harm plants. You can filter you water with an inline filter designed specifically to remove calcium or hard water deposits. Get a pH testing kit and use pH Down to adjust your water. These kits are commonly found in hydroponic shops or online.