May 13, 2013 04:01

Hydroseeders ... is bigger better?

Have you ever wondered about the size of hydroseeders and the type of machine that is right for you? In this article, I’ll address the pros and cons of   large and small hydroseeders. Suppose you were called in to hydroseed 1,000 square feet at a client’s residence— would you bring in a piece of    equipment that has a 4,000-gallon capacity? Probably not. If you had a smaller capacity hydroseeder, surely you would use that, because it would be more efficient than bringing in a larger unit.

The interesting part is that you can get hydroseeders that come in all sizes and shapes. There are many good machines on the market, ranging in size from 100 gallons to 4,000 gallons. This equipment, depending on the configuration, can cost anywhere from a few thousand dollars up to $25,000. Then there is specialized equipment that costs more than $100,000. These are the large machines on big trucks.

Small machines have smaller motors and pumps, but the primary functional difference is simply that the tank is smaller. Most machines, large and small, do about the same thing. It just takes more tank loads of application with a smaller machine to do what a larger machine might do in one or two tank loads. With such a wide range in costs, some large machine buyers might be better off with a less expensive, smaller machine.

In fact, two medium-sized machines may cost a lot less than one large machine and provide significantly more versatility. If you have one or two jobs a year of 10 acres or more, a few in the five to 10-acre range, and other smaller jobs, then small machines with lower price tags may be the better choice. You do not really need a $100,000 or even a $50,000 asset sitting in your yard most of the time, if a $25,000 setup will do your work in a timely manner.

The price tag of the machine is only one part of the cost equation; the expense of transporting the machine should also be considered. Larger machines are mounted on big trucks dedicated to the machine. A decent used truck suitable for hauling a large hydroseeder will cost $25,000 or more; the cost of a new truck to carry a large hydroseeder is even more expensive.

Smaller machines (1,200 gallons or less) can be mounted on a dedicated trailer or placed onto a utility trailer. Utility trailers are frequently called for when the machine is only used some of the time; it can be available for other purposes when the hydroseeder is removed.

A new trailer for 1,200-gallon machines (or smaller) will cost


from $2,500 to $5,000, depending upon capacity. Another issue affecting a decision regarding the size of the machine is the driver’s license requirements. A commercial driver’s license is required for rigs exceeding 26,000 pounds. With machines in the 800- to 1,200-gallon size range, state laws regarding trailer weights must be obeyed; however, a commercial driver’s license in not required in most states. Some states also have restrictions regarding trailers with tanks holding more than 1,000 gallons.

With an overall investment ranging from less than $10,000 to well over $100,000, spending more time determining the capabilities of small or medium-sized machines may help avoid the “overbuying” mistake. Because it’s not good, from a cost-effective point of view, to have a large piece of equipment sitting idle for periods of time.

Large machines, jobsites and productivity

Types of jobsites, as well as conditions on a particular jobsite, can affect the size of the machine best suited for a job. Highway construction projects or mine reclamation projects are usually ideal for large machines. These jobs can easily be 10 acres, and sometimes exceed 100 acres. These jobs are also highdollar tasks, justifying the large capital investment for a large machine and truck.

Large machines are good for big jobs, because they are capable of pumping more than 300 gallons per minute from a tower gun. Such a discharge rate will result in the tank of the machine being emptied in about 15 minutes. Reloading and mixing large machines can take 15 to 20 minutes. It may be possible to apply more than 50,000 gallons of mulch slurry in a single workday. When mulch application rates are low (1,200 lbs. per acre), as much as 15 acres might be completed in a day. If the mulch requirement is 2,000 lbs. per acre, then about 8½ acres may be completed in one workday.

Reloading the tank quickly is also the key to productivity. If a suitable water source is a great distance from the jobsite, a water tanker truck can be used to bring water to the machine, instead of the machine traveling to the water.

A lot of revenue-producing time (applying mulch) can be preserved by bringing water to the machine. However, the cost of providing a tanker for refilling is not justified if the machine can drive to the water source in a minute or two. The tanker trucks will not speed up the operations enough to justify their costs.

On the surface, one would think that hose applications take away the high-volume application of tower spraying achieved with a large machine. This is because spraying with a hose limits discharge to 40 to 50 gallons per minute. This limit is necessary because a person cannot hold the hose with higher volumes, due to the back pressure.

A large machine can become more efficient, however, by using two or more hoses, with additional people spraying at the same time from the same machine. Most large machines will easily produce enough flow for two or three hoses, and some large machines may support as many as four or five hoses of simultaneous application.

Large machines are needed for big jobs, and are easily justified with jobs paying the big bucks. Whether jobs are to be large acreage with tower applications and moderate mulch rates, or jobs calling for hose applications with heavy mulch rates, if the jobs are large enough and pay enough, then big machines can be the best investment. On the other hand, if you only have a few large jobs a year, then a small machine with a lower price tag is probably the better choice.

Smaller machines are sometimes a better choice

Jobs requiring hose applications are more commonly completed with smaller machines. Smaller machines are more versatile and more easily moved around an otherwise difficult-to-navigate jobsite.

Some jobs will have restrictions or obstacles that rule out the use of a large machine. For example, on golf course construction, the general contractor may not permit the weight of the machine on the site. On some reclamation projects, the terrain may not be suitable for larger truck-mounted machines. Other conditions at jobsites may also prohibit a large rig getting to where it needs to be.

A smaller rig is easier to transport to a work area, compared to a large truck. Smaller machines are sometimes better for hose applications. Reloading a 500- to 600-gallon machine can actually be done in as little three or four minutes; reloading a 1,200-gallon machine can be done in as little as six or seven minutes. With hose applications, you can sometimes actually put out more product per hour than with a larger machine. One other note: some small machines utilize gear pumps, a definite advantage to pumping thick mulch materials through long hoses. Hose applications are necessary on some utility right-of-way projects.

These sites can have long slopes where long hoses are necessary to reach the area to be sprayed. Hose applications are also required to apply mulch products designed to replace erosion control blankets. This requirement is to assure total and consistent mulch coverage of these high-end products.

Auxiliary water tanks as an alternative

A well-established trend has contractors purchasing less expensive and smaller machines. These pieces of equipment are mounted on a heavy-duty utility trailer, along with a plastic water tank. This plastic tank is large enough to carry the water needed to refill the machine at least once.

With this machine and tank combination, the operator can make a batch of slurry in the hydroseeder tank while at the water source, and also while fill the plastic water tank. At the jobsite, the first tank load is applied to the site; then water from the water tank is used to make a second batch in the hydroseeder without having to go back to the water source.

A plastic water tank with the capacity to make two additional tank loads is even better. With this combination, a contractor has the ability to make three tank loads of application with only one trip to the water source.

A contractor with a Card machine as small as 390 gallons and an auxiliary water tank can apply up to 4,000 lbs. of mulch a day, assuming that the water source is not too far away. This is enough to do two acres of standard mulch application, or more than one acre of erosion control blanket replacement mulch application. There is a contractor in Rhode Island who has two 1,000-gallon water tanks coupled with a 425- gallon machine. He can easily do more than a third of an acre with  850 lbs. of mulch application with a hose in about 90 minutes.

Stepping up to a slightly larger machine, a well-equipped 700-gallon machine can be purchased for about $25,000. A 725-gallon plastic water tank can be purchased for another $750. Spraying with one hose will empty the tank of a 700- gallon machine in about 15 minutes. Using two people with two hoses cuts the application time in half.

So two people working can empty the tank in about eight minutes. Reloading with the auxiliary water tank takes about six minutes. If water is close by for refilling, at least three tank loads per hour can be applied (750 lbs. of mulch per hour). This is enough mulch to cover three acres a day using 2,000 lbs. per acre rate, or about 1¾ acres a day with 3,500 lbs. per acre (the rate required for erosion control blanket applications. 

Large hydroseeders are best for big jobs utilizing tower applications, which are primarily used where large areas need to be seeded quickly and inexpensively. Small hydroseeders are usually better for smaller jobs that need hose applications. Hose applications are best for landscaping jobs requiring consistent mulch coverage and even seed germination.

Hose applications are required for erosion control jobs utilizing mulch products designed to replace erosion control blankets. Gear pump machines are better for this type of application. There is no rule-of-thumb defining what constitutes a large machine and small machine; there are no rules defining what constitutes a large job and a small job.

The fact is that when a job calls for hose applications, contractors with small machines can compete with the big boys. In some cases, a small machine may even be more efficient.

EDITOR’S NOTE: Jim Lincoln has more than 30 years experience in hydroseeding. He is the president and owner of TurfMaker.

Also in Soil Erosion News

In many ways, we are fortunate that, in our chosen profession, we are able to help people when certain disasters occur: the tornadoes in Missouri, Oklahoma, Louisiana and Georgia, the flooding in Louisiana, the snows in the northeastern part of the country, the rain in California, and the snow in Colorado....

Do not miss another issue.
Read the new issue of Soil Erosion Magazine online