This blog post gives an overview of the sprinkler nozzels available on the market, also known as spray nozzles or sprayers. Sprayers release the water like a shower head in a torrent in all directions to be sprinkled. Unlike the geared sprinklers, which rotate and only eject the water in a specific direction in a concentrated jet. These are covered in a separate blog post on rotating sprinkler performance data.

Spray nozzles are used for irrigating rather small areas and release a relatively large amount of water to the irrigated area in a short time, so they have a high precipitation rate. Accordingly, they must not be mixed in a sector with geared sprinklers, which have a significantly lower precipitation rate, and they can only irrigate a smaller area in a sector than would be the case with geared sprinklers. An exception here are the rotating nozzle sprinklers, which are a cross between spray sprinklers and rotating sprinklers. These do not emit the water in torrents, but rather in fine jets due to their rotating nozzle and therefore also have a significantly lower precipitation rate than standard sprayers.

Spray sprinklers use less water pressure than geared sprinklers. They are best used for irrigating small areas up to a maximum length of 13 to 16 feet with a floor plan with many curves or corners. The targeted sprinkling of individual trees or bushes that have a very high water requirement is also a possible using scenario.

Separation of nozzle and body

Unlike geared sprinklers, spray sprinklers have a separate nozzle and body. So you don’t buy the complete spray sprinkler, but a spray nozzle and a body and then combine these two to form the sprinkler. This has the advantage that, depending on the application scenario, you can combine a specific nozzle with a specific body that is best suited for the scenario. It is also practical to use, since if a nozzle is defective or if you are experimenting with different nozzle types or sizes, you only have to unscrew the nozzle from the body and screw in a new one instead of digging out the entire sprinkler and installing the new one.

The nozzle of the spray sprinkler differs significantly from the nozzle on the geared sprinkler: With geared sprinklers, most sprinklers come with entire nozzle sets, sometimes with up to 8 or more different nozzles. These are small nozzles measuring maybe 0.5 x 0.5 inches, of which you insert the desired one into the sprinkler riser. The nozzles of the nozzle sprinkler, on the other hand, are much larger and combined with a filter. You screw it on top of the riser of the body. You don’t buy a set of nozzles here either, but rather the exact nozzle you want, i.e. the type of nozzle you want with the desired throw range. The nozzle also makes up a larger part of the total sprinkler price for spray sprinklers compared to geared sprinklers. This is especially true for rotating nozzle sprinklers, where the nozzle, filter and rotating mechanism make up the actual sprinkler and the body accounts for the smaller part of the cost.

In the following, I will present the nozzles available on the market across all brands, together with their specific performance data. The matching bodies can be found in a separate blog post.

As a beginner, you can easily be overwhelmed when it comes to the nozzles, as there are a large number of different nozzles on offer, the difference between which is not immediately apparent at first glance and which also have different designations depending on the manufacturer.

Fixed arc nozzles

These nozzles spray a fixed part of a circle, 90 degrees, 180 degrees or 360 degrees, depending on the nozzle selected. A sector deviating from this cannot be irrigated. The advantage is that they reliably irrigate the predefined sector, you don’t have to set it up and it can’t be adjusted. In addition, the precipitation rates of the different sector sizes are coordinated within the same nozzle size, so that a uniform precipitation rate (MPR) can be achieved if only one nozzle size is used within an irrigation sector.

Variable arc nozzles

With these nozzles, the sector to be irrigated can be variably adjusted. You don’t need a nozzle that is tailored to the section of a circle, but you can flexibly define the section to be sprinkled on the nozzle, which gives you greater flexibility.

MPR nozzles

The precipitation rates of these nozzles are matched to one another, so that you always have the same precipitation rate (MPR) even when using different nozzle sizes. The Rain Bird and Toro nozzles work like the typical spray nozzles, so they have a comparatively high precipitation rate. The MPR nozzles are fixed sector nozzles. Depending on the sector size to be irrigated, you have to use the desired sector model, e.g. full circle, semicircle or quadrant. At Rain Bird, the MPR nozzles also have the same precipitation rate across sectors. At Toro, the same precipitation rate only applies to the different nozzle sizes with the same radius – and again only approximately.

Rotating nozzles (rotating nozzle sprinklers)

This is actually a separate sprinkler category that no longer has much in common with the original nozzler sprinkler (sprayer), but is more of a cross between a sprayer and a geared sprinkler. The nozzle head includes a rotation mechanism that ensures that the water is not released in a gush, but divided into jets and that the jets are released at different points parallel to the rotation of the nozzle head. As a result, the precipitation rate is significantly lower than with a conventional sprayer. With the amount of water available, you can irrigate a much larger area at the same time. In return, however, it has to be watered longer than with conventional nozzles.

The radius of the rotating nozzle sprinklers is also greater than that of conventional nozzle sprinklers and reaches up to 35 feet. All three rotating nozzle sprinklers presented automatically also provide MPR, i.e. they are also MPR nozzles at the same time. The nozzles are a cross between nozzles with a fixed arc and nozzles with a variable arc: Different nozzles are required to cover all sector sizes, these can be adjusted within a specified range, e.g. 90 to 210 degrees or 210 to 270 degrees. Only the nozzle to cover a full circle (360 degrees) is not adjustable. The Hunter MP Rotator is my top pick for a sprinkler.

Bubblers

Deliver water directly to the root area of the plant. This comes out with minimal pressure and hardly any throw distance directly at the nozzle or in the immediate vicinity of the nozzle and is released at close range to the ground surface. Depending on the model, this can be done either in surges in the form of an umbrella or divided into jets. Bubbler nozzles are used for watering individual trees or shrubs that require more water than the surrounding vegetation, or for watering very small areas.

In addition to the above, there are the following types of nozzles for special tasks:

Strip nozzles

Used for watering narrow, rectangular areas (lawn strips). Three different nozzles are always required to water a rectangle (nozzle in the left corner, nozzle in the right corner, nozzle in the middle).

Short radius and stream spray nozzles

Short-radius nozzles are nozzles with a short throw distance that is always the same, regardless of the water pressure, for watering in very small spaces. Stream spray nozzles divide the water jet into individual jets and have a lower precipitation rate compared to conventional spray nozzles.

You can find the right bodies to turn the nozzle into a nozzle sprinkler in a separate blog post.

The correct placement of the sprinklers on the area to be irrigated is one of the most important points when planning an irrigation system. Firstly, this is crucial for watering the garden as evenly as possible and consequently saves water. And secondly, incorrect positioning can often only be corrected later with great effort.

When positioning sprinklers, a distinction is made between a square pattern and a triangular pattern. These two are the dominant principles around the world by which most irrigation is planned. The square pattern described below is the technique that is somewhat easier for the user to implement and is particularly suitable for rectangular areas. In the following blog post you can find out how it works, what its advantages are and how the square pattern is reflected in the performance data of the sprinkler manufacturers.

The basic principle of the square pattern is the principle of double overlap: each sprinkler must be reached by the throwing circles of (at least) two other sprinklers. For example, this can look like this for a square basic shape:

A sprinkler is placed in each corner. This is reached by the throwing circle of its left and right neighbor sprinkler (= double overlap). On the planning page you will find further examples for the placement of sprinklers in different basic shapes.

In the square pattern, 4 sprinklers are placed in such a way that – if you mentally connect the sprinklers – a square results. These 4 sprinklers together correctly cover the square area they enclose – according to the rules of the square pattern. The distance between the sprinklers in the square pattern is approx. 50% of the sprinkler throw diameter, i.e. approx. the throw range (= radius) of the sprinkler. For example, if you have a 30 foot throw, the sprinklers will be positioned 30 feet apart.

Before starting, the ground plan of the garden – if it does not already consist of a square or a rectangle – is divided into rectangular parts. You can find an example of this in the planning section. When drawing in, start with the trickiest spots – these are the 4 corners of the area to be watered. A sprinkler is placed in each of these, throwing a quarter circle:

Next, proceed to the second most delicate area: the edges. The sprinklers are set on the edges with half-circles in such a way that they correctly overlap their right and left neighbor sprinklers. Your throwing circle must therefore reach to the neighboring sprinklers. It then looks like this:

Before drawing in the other sprinklers, you can make auxiliary lines. To do this, connect each of the sprinklers on the edge, with the exception of the corner sprinklers, to the sprinkler on the opposite side. On the plan, this results in a checkered pattern:

Full-circle sprinklers are now drawn in at the intersections of the auxiliary lines. After the first circumnavigation it looks like this (I have removed the auxiliary lines for the purpose of a clearer representation):

An unirrigated spot remains in the middle. This is now also filled with full circles. This ultimately leads to the following result:

You can see that there is a continuous pattern over the entire irrigation area, which always looks exactly the same within 4 sprinklers. This consistent pattern means the lawn is watered evenly across the entire area. This means that all areas of the lawn receive the same amount of water.

In my example, it is exactly the case that the set full and semicircles result in exactly the length and width of the area to be irrigated. In practice, this often does not turn out so well, so that, for example, a horizontal and/or vertical area remains that is only half the diameter of the circle, for example. Here you can then either strictly follow the principle further and thus accept a larger than planned overlap at this point. Or you try to cushion this effect of the additional overlap by reducing the throwing circle or choosing smaller nozzles for the sprinklers in question in order to achieve the same amount of precipitation as possible as in the other squares. A third possibility is the use of MP Rotator sprinklers, which independently keep the amount of precipitation constant (more on this below in the chapter “Sprinklers with integrated MPR function”).

Reference to square and triangle pattern in sprinkler operating data

The sprinkler manufacturers indicate the precipitation rate for their sprinklers in their product descriptions. This is done for a specific water pressure and a specific nozzle used with reference to the square or triangle pattern. Following is an example:

Rain Bird 3500 Series

If you irrigate according to the principle of the square pattern, then the lawn receives 0.37 inches of precipitation per hour at 25 psi. This corresponds to 0.23 gallons per square foot.

Note: The 0.23 gallons per hour does not refer – as is often wrongly believed – to the one sprinkler listed on its own, but is only achieved if this sprinkler is operated together with others in a square pattern. So if there is a proper overlap. The one sprinkler on its own would have a much lower precipitation rate, which would be only a fraction of what it was advertised to be! You can calculate this relatively easily by calculating the area of ​​the circle and then dividing the flow rate by the area. In the example, with a throw distance of 27 feet, we would have a full circle with an area of ​​2,289 square feet (27 x 27 x 3.14). If you divide the amount of water available per hour of 84 gallons by the number of square feet, you would arrive at a rainfall of just 0.037 gallons/hour per square feet. Even if you operate the sprinkler not as a full circle but as a quarter circle, only 0.15 gallons per hour would result.

Adjust precipitation – use of appropriate nozzles

When placing the sprinklers, you must ensure that the amount of precipitation from the sprinklers must be adjusted depending on the size of the sector of the circle. Why? Most sprinkler models always release the same amount of water in a certain amount of time, e.g. 200 gallons/hour at 30 psi pressure. If the sprinkler is set to full circle, it would distribute these 200 gallons in a full circle. The sprinkler starts at a certain point and then slowly rotates until it has completed the full circle. Then he does it all back in the opposite direction. If the sprinkler was set to a quarter circle, it would also pour 200 gallons per hour, but spread the water over an area that is only a quarter as large. The areas irrigated with a quarter circle would receive four times as much water in the same period as the areas irrigated with a full circle. And the areas irrigated with a semicircle would get twice as much as those irrigated with a full circle.

This effect is compensated for by the nozzle size of the sprinkler. So you change the nozzles of the sprinklers in order to have the same precipitation rate for everyone. The semi-circle sprinklers have nozzles with twice the flow rate as the quarter-circle sprinklers. And the full-circle sprinklers have nozzles with twice the flow rate of the half-circle sprinklers. In our example, the full circle sprinkler would pour 200 gallons per hour, the half circle sprinkler about 100 gallons and the quarter circle sprinkler about 50 gallons per hour. Each quadrant would therefore get the same amount of water of about 50 gallons per hour. The sprinkler manufacturers usually reflect this system in the classification of their nozzles: A No. 4 nozzle has twice the flow rate as a No. 2 nozzle a No. 8 nozzle has twice the flow rate as a No. 4 nozzle.

So you could think that the quadrant sprinklers could simply be equipped with No. 2 nozzles, those with a semi-circle with No. 4 nozzles and those with a full circle with No. 8 nozzles and thus achieve the same precipitation rate for all. Unfortunately, it’s not quite that simple! The problem is that using different nozzle sizes also affects the throw distance of the sprinklers. With the same water pressure, larger nozzles lead to greater throw distances, smaller nozzles to shorter throw distances. It is therefore not possible to depict a correct square or triangle pattern in this way, since the same throwing distances are required for these, regardless of the size of the sector of the circle!

The sprinkler manufacturers have solved this problem with the introduction of so-called MPR nozzles. MPR stands for “Matched Precipitation”, i.e. the principle of matching the precipitation rate to one another. An MPR nozzle set contains 4 nozzles for 90 degrees, 120 degrees, 180 degrees and 360 degrees. Depending on which section of a circle you want to sprinkle, you use the appropriate nozzle in the sprinkler. This not only adjusts the precipitation rate, but also results in an identical throw distance. All 4 included nozzles therefore have the same precipitation rate and throw distance at the same water pressure.

Important: When choosing a sprinkler, make sure that the sprinkler is MPR-capable! This only applies to the newer model generations, older sprinklers cannot handle MPR nozzles or MPR nozzles are not available for them at all.

A possible alternative to adjusting the precipitation rate using MPR nozzles would be to group together sprinklers with the same sized circular sections in one sector and to achieve the same amount of precipitation over different irrigation times. So let the sector with the full-circle sprinklers run 4 times as long as the one with the quarter-circle sprinklers.

Sprinklers with integrated MPR function

Hunter’s MP Rotator sprinklers go one step further. These already have the MPR function built in: If you adjust the radius or the circular section to be irrigated, the sprinkler automatically adjusts the water flow to the same extent, so that you always have the same precipitation rate. In addition, the precipitation rate of the MP-Rotator is always the same for all models, so that different models can be mixed in one sector without any problems.

Below is a link to MP Rotator sprinklers and the associated bodies on Amazon:

The Hunter MP-Rotator sprinklers are my top recommendation for the realization of a garden irrigation. They contain a number of useful functions that will help beginners in particular to get everything right. And which make planning much easier for both beginners and professionals.

• Matched Precipitation Rate (MPR): The Hunter MP Rotator automatically ensures that every patch of lawn receives the same amount of water in the same amount of time. To do this, it automatically adjusts the amount of water when a larger or smaller radius or a smaller or larger section of a circle is watered, so that the precipitation rate always remains constant at around 0.4 inches per hour. This also works automatically across different MP rotator models; you can mix models in one sector without any problems. As a result, users no longer need to think about coordinating the amount of precipitation, which is otherwise a very complex matter. The matched precipitation rate ensures that no spot is unnecessarily watered too much and thus also saves a lot of water.
• Automatic pressure regulation: By combining it with the appropriate pressure-regulated body (Pro Spray PRS40), the pressure on the sprinkler is automatically reduced to a maximum of 40 psi. Operation at 40 psi is the variant recommended by Hunter, in which the sprinklers have the ideal spray pattern. If the water flow test results in a lower pressure value for operating the sprinkler, the Pro Spray PRS30 body can alternatively be used, which reduces the pressure on the sprinkler to a maximum of 30 psi. This saves you from having to think about how the sprinklers in the pipeline are ideally placed in order to achieve the most even pressure distribution possible. and you can also be sure that the sprinklers are working with 40 or 30 psi pressure (provided there is sufficient outlet pressure).
• Slow watering: A low rainfall rate of 0.4 inches / hour ensures that the lawn is watered slowly. This may sound like a disadvantage to laymen, but it is an immense advantage! Due to the low precipitation rate, the MP-Rotator has a low water consumption compared to other sprinklers. This means that more sprinklers can be operated in one sector with the amount of water available. So you need fewer sectors and simply let the sprinklers run longer. If you have little water volume and water pressure available from the outset, then the MP rotator can be the way out to be able to irrigate at all. In addition, the low precipitation rate saves water because the lawn can also absorb all of the water with this slow irrigation. Hunter puts this saving at 30% compared to traditional spray nozzles.

There are also the following advantages, which are also known from other Hunter and Rainbird products:

• Manual throwing distance reduction: The throwing distance can be continuously reduced by up to 25% on all MP Rotator models.
• Precise adjustment: The throwing range and pitch circle can be precisely adjusted continuously
  

  The setting of the circular sector and throwing distance is particularly easy with the MP rotator setting tool

• Separation of body and nozzle: This means that unsuitable nozzles can be replaced with just one movement and, in borderline cases, you can find the ideally fitting nozzle very easily and flexibly by trial and error. If a sprinkler is defective, it does not have to be completely dug up, but the nozzle is simply replaced.
• Color coding: Allows quick and easy differentiation of the nozzles

The MP Rotator sprinklers are currently the only sprinklers on the market that have all of the advantages listed. They differ fundamentally from other sprinklers in some points and, as rotating nozzle sprinklers (also known as multi-jet rotary sprinklers), form a separate product group. Unlike nozzle sprinklers, they do not give off the water in a surge, but instead break it up into many fine water jets by rotating the nozzle. The MP rotators are also very different from other Hunter sprinklers. That’s because they weren’t originally developed by Hunter, but by the Walla Walla Sprinkler Company. This pursued a completely different technical philosophy than the competition and created a revolutionary product. In 2007 this was added to the Hunter product range through a takeover of the company. It is ideal for small to medium-sized gardens.

The MP rotator is offered in the following models:

• MP1000 (throwing distance 8.2 to 14.8 feet)
• MP2000 (throwing distance 13.1 to 21.0 feet)
• MP3000 (throwing distance 22.0 to 29.8 feet)
• MP3500 (throwing distance 30.8 to 35.1 feet)

There is also the 800 series, which, at 0.8 inches / hour, has a different precipitation rate than the models described above and is therefore not suitable for combination with these. The 800 series is designed for very small areas.

• MP800 (throwing distance 5.9 to 11.5 feet)
• MP815 (throwing distance 8.2 to 16.0 feet)

There are also 3 models with which you can specifically water a narrow strip of lawn:

• MPLCS515 (is placed in the left corner of the strip)
• MPRCS515 (is placed in the right corner of the strip)
• MPSS530 (is placed in the middle)

And last but not least, a model that is especially suitable for irrigating a small corner:

• MPCORNER

For the implementation of your irrigation, I recommend using the models MP1000, MP2000 and MP3000!

These three models cover a throw range from around 10 feet to 33 feet (at 40 psi pressure). This is completely sufficient for small and medium-sized gardens and normally gives you plenty of variation options. Since all manufacturers are optimistic about throwing distances, it is best to subtract 10% from the manufacturer’s values ​​when planning your planning!

Although the sprinklers have the same precipitation rates of around 0.4 inches per hour, you should, as far as possible, use the same model with the same throwing range in a sector in whole or in large part. In this way, you can correctly water your lawn according to the principle of the square formation or, alternatively, the triangle formation. For example, you plan to water the lawn according to the square formation with the largest model MP3000 and use the smaller models MP2000 or MP1000 in the edge areas that remain and where there would be unnecessarily large overlaps when using MP3000 models.

With the MP3500, you can alternatively use a sprinkler with a throwing distance of even 35.1 feet, which also has the same precipitation rate. However, it is currently only offered in a single model variant (90 to 210 degrees), so I would not consider this sprinkler in the basic planning and only use it in the worst-case scenario – if, for example, two ore three excess feet are still missing in an edge area.

In my opinion, only for large gardens it is worthwile – due to the higher possible throw distances – to consider using traditional geared sprinklers instead of MP rotators. For gardens of up to 11.000 sqare feet I would definitely use the MP rotator because of the many advantages.

The MP rotators cannot – as is usual with geared sprinklers – be set for any sector of a circle. Instead, depending on the desired application, one of 3 model variants can be selected for both the MP1000, MP2000 and MP3000. Using the MP3000 as an example:

• MP3000-90 (circular sector adjustable from 90 to 210 degrees)
• MP3000-210 (circular sector adjustable from 210 to 270 degrees)
• MP3000-360 (fixed 360 degree circle sector)

The model variant -360 is used when you want to irrigate a full circle with the sprinkler. This can only be used for exactly this purpose! So you can not only rain 270 degrees with it and leave the remaining 90 degrees unwatered. Instead, the -210 model variant is intended for irrigation of a three-quarter circle. In any case, this must have a circular sector of at least 210 degrees and can irrigate a maximum of a circular sector of 270 degrees (= three quarters of a circle). The last of the three models -90 can be used for watering a quarter circle (90 degrees) as well as for watering a semicircle (180 degrees). It has to rain at least a sector of a circle of 90 degrees and goes up to a sector of a circle of 210 degrees, i.e. slightly larger than a semicircle.

With the MP-Rotator, the sprinkler and body are separate! Only the sprinkler itself is sold as an MP rotator. In order to be able to use it, a suitable body is required, i.e. the suitable “housing” to which the pipeline is connected and from which the sprinkler can rise. The MP-Rotator Sprinkler is simply screwed into the body and can be changed in a few seconds. In order to take full advantage of the sprinkler, you should use a pressure-regulating body. 2 models are offered:

• Pro spray PRS30 (30 psi)
• Pro Spray PRS40 (40 psi, optimal spray pattern)

The PRS30 automatically regulates the pressure arriving at the sprinkler to a maximum of 30 psi, the PRS40 to 40 psi.

Both bodies are offered in 4 riser versions, using the PRS30 as an example:

PROS-00-PRS30 (standpipe sprinkler for shrubs)
PROS-04-PRS30 (pop-up height 4 inches)
PROS-06-PRS30 (pop-up height 6 inches)
PROS-12-PRS30 (pop-up height 12 inches)
The number in the model number stands for the pop-up height, i.e. the height that the sprinkler moves out of the ground when irrigation starts, in inches. Normally you will choose the 6 inches or 4 inches variant, the 12 inches variant may be used if there is an obstacle in front of the sprinkler. The standpipe sprinkler will not be used in the usual private garden, it does not sink and therefore stands in the way after the work is done (tripping hazard).

Below is an excerpt from the range of MP-Rotator sprinklers and associated PRS30 or PRS40 bodies on Amazon: