Duration of Irrigation

Q. How long do I leave it on?

Periods of 10 to 15 minutes, once a day in cooler conditions possibly two or three times a day in warmer temperatures should be enough in most cases.

Depending on the extent to which you have slope, you will probably require 20 to 30 minute irrigation cycles, once or twice a day in cooler conditions and three or four times a day in summer.

Q. How do I determine whether my plants are getting enough moisture?

A. Test your requirements 30 minutes after irrigation by tipping out a few pots at random and checking the moisture in the pot media. The media should be moist, not wet, reasonably close to the media surface. If not, you may need more frequent or longer irrigation cycles.


Do not over-water. You will need to keep the following in mind:

Ebb & Flow MAT irrigation is very different from overhead irrigation. The fact that you may not see water or that the tops of pots are dry does not mean that plants are not getting sufficient water. It may just mean that water is being used better, that the general area around the pots is drier and that you have less weed and algae problems.

The components of the Ebb & Flow MAT are carefully matched to provide particular water supply, water holding, drainage and other characteristics. If you over-wet the beds you may surrender some of the mat's benefits. Where irrigation needs are above normal, as with some side-tailed benches, it is suggested that irrigation periods be lengthened rather than attempts made to increase water flow. If puddles or significant water are visible on top of the Ebb & Flow MAT you are probably over-watering. Alternatively, your bed may need to be made more even in grade.

Inadequate siphoning of excess water from your bench or bed is also a possible reason. You may need to increase the overhang of mat over the side or end of your benches, or ensure that the mat is properly tailed off into a dish drain at the end of your outdoor bed.

Drying Out

QWhat happens if the Ebb & Flow Mat dries out completely?

A With correct irrigation, the central layer of the Ebb & Flow Mat should never dry out completely, and the design of the system requires this to be so. For this reason, our installation procedures require you to saturate the mat by hose before you first use it.

However, if the mat does dry out, all you need do to reactivate the system is to apply a little wetting agent or household detergent and water it in across the full length and width of mat surface. This will break the surface tension and allow irrigation water to spread more easily.

QWhat do I do if I see a dry patch?

AYou follow the same procedures as if the whole mat had dried out, but limit the addition of wetting agent or household detergent to the area affected.

Containers & Media

Q. What type of containers can I use?

A. You may use bottom-drainage pots or standard pots with side drainage holes that come close to the bottom of the pots. Side drainage pots - A ring of water rises around the edge of each pot when placed on Ebb & Flow Mat and this can make capillary contact with the media through side drainage. If the side drainage hole is more than 1/16 inch above the bottom of the pot, capillary contact may not be made, and the pot may not be suitable for Ebb & Flow Mat irrigation.

Q. What media should I use?

A. General nursery mixes are fine for Ebb & Flow Mat. Mixes containing peat and/or coir offer good capillarity and are ideal. However, orchid mixes generally have low capillarity and may not be suitable and you should do a trial. Mixes with very large particles may be unsuitable for Ebb & Flow Mat and should be tested for capillarity prior to use.

Effects of Roots

Q. Will roots grow into the Ebb & Flow Mat?

A. Ebb & Flow Mat irrigation is based on cyclic watering and long periods of free drainage, ensuring that the top layer of the mat remains dry for most of the time. This encourages air pruning of roots and lessens the likelihood of their penetrating the Ebb & Flow Mat. Of course, roots will grow into almost any substrate if this is left wet long enough. As a rule of thumb, if pools of water remain 15 minutes after stopping irrigation, you have either had a period of extended rain or you are almost certainly over-watering or not draining properly. You can apply copper based materials to the mat mixed with water based paint (Check with the manufacturer).

Sloping Sites

Q. Does Ebb & Flow Mat irrigation need a sloping site or can Ebb & Flow Mat work on a sloping site?

A. Ebb & Flow Mat irrigation will work on level sites and is best at slopes of 1-2%.In some cases it can be used on a slope of up to 6%. The following comments apply to particular uses:

Indoor Benches

Dead flat benches can be used as long as you have an overhang of mat on the end or edge to create a siphoning effect and assist with drainage. However, you will need a lip of ½” (max.) height at the edge where the overhang is located to slow drainage of water from that part of the mat.

Steep Sites (4 to 6%)

If a grower has a steep site then there are specific tips to slow the water movement down the sleeves especially for side slopes .One strategy is to lay the mats across the slope and this will give you a faster drainage cycle and allow beds up to 800’ in length. Please contact manufacturer for more details.

Ancillary Equipment

QWhat pressure do I require?

A 10 psi to 15 psi is required. If you have higher water pressures, you will need a pressure reducer.

Q What fixtures do I require?

A Besides the Ebb & Flow Mat, you will require connections to your water source, an in-line filter (120 Disk Filter) with flushing capability and perhaps a pressure reducer (10 to 15 psi).

Q How long will the Ebb & Flow Mat last?

A This depends on the way you treat the mat and whether it is exposed to extreme weather conditions. As a guide, the Ebb & Flow Mat should last five years or more under normal conditions and treatment (where tractors are not driven over the mat). Note: This is not to be considered a warranty but a guide only.


Q. Will salts build up in my pots, given that the water flow to plant roots is in the opposite direction to overhead irrigation?

A. Tests have shown some increased salinity in the very top layer of media in pots irrigated using Ebb & Flow Mat. However, the same tests showed salinity in the root zone to be lower than similar pots irrigated by overhead means. No evidence of salt injury has been recorded in commercial nurseries to date.


Q. Do I need to sanitize my Ebb & Flow Mat’s?

A. Under normal operation, drainage will clear excess water from the mat when irrigation ceases, and the residual water is subject to a flushing action when irrigation re-commences. However, chlorination or similar action is highly desirable. In addition, some certification requirements may make sanitizing mandatory.

Keys to Success

Is the slope of the bed or bench in excess of 6%?

1. If so you’ve exceeded design parameters of Ebb & Flow Mat and should consult supplier’s technical staff for assistance.

Is your slope between 4 and 6%?

2. If so and the system still gives you trouble after checking out all other factors listed here, please consult your supplier.

Did you thoroughly water your Ebb & Flow Mat before using? Did you then use the mat immediately for irrigation?

3. Installation instructions require the Ebb & Flow Mat to be thoroughly watered by hose before initial use. However, if you let the mat or part of it dry out completely before you start using it for irrigation, this defeats the purpose of the original wetting up and you will need to do this again, in this case adding a little wetting agent as you do so.

Did you water your containers thoroughly before putting them on the Ebb & Flow Mat for the first time?

4. Initial watering of containers is important, particularly if you are dealing with plugs or immature plants with undeveloped root systems. Pre-watering of the container allows initial capillary connection to be established quickly. Subsequent, regular Ebb & Flow Mat irrigation should then be able to fulfill the plants’ needs.

If part or the entire Ebb & Flow Mat was allowed to dry out, did you add wetting agent to the irrigation water?

5. Whenever any part of the Ebb & Flow Mat dries out completely, water flow is impeded. You will need to use a small amount of wetting agent to allow irrigation to re-establish itself. You will not normally need to use wetting agent again until the mat dries out again.

Are you using the recommended header pipe with drip emitters?

6. If not, please consult your supplier’s technical staff.

Is your water pressure between 10 and 15 psi and the flow rate at least 7 gallons?

7. If your water pressure is less than 10 psi; you will not receive enough water. If your pressure is over 15 psi, consult your supplier as you are above the design limits of the drip-tape used in Ebb & Flow Mat. If the flow rate is too low this will not deliver the amount of water required to wet up the mat

Have you too many beds or benches connected to one solenoid?

8. If you have too many beds or benches connected to the one solenoid, this will reduce the pressure of water reaching your beds or benches. This can cause portions of your Ebb & Flow Mat installation to receive insufficient water, particularly if your installation has a significant slope. As a guide approximately 300 lineal feet of mat for one solenoid is the maximum run if the flow rate and pressure are as required above.

Are you employing irrigation from the one side with an overhang of the Ebb & Flow Mat on the other side?

9. If so, you will need a lip of ½” (max.) height at the edge where the overhang is located to slow drainage of water from that part of the mat.