Compost tea spray rig PSI

Discussion in 'Organic Lawn Care' started by ICT Bill, Mar 25, 2009.

  1. ICT Bill

    ICT Bill LawnSite Platinum Member
    Messages: 4,115

    I have been asking around as I have been traveling about the typical PSI on the spray rig while spraying compost teas. I am not an applicator and do not have a lot of experience with different spray rigs. Some say as high as 200 PSI while others say they never get above 80 PSI

    What type pump do you use and what is the typical PSI while applying to lawn and landscape. I understand if you are trying to reach 60 feet into a tree you will have to crank it up, but what is typical for lawn and landscape??
  2. hunter

    hunter LawnSite Senior Member
    from Texas
    Messages: 254

    For lawns and shrubbery we use just a 50psi 12volt pump. Don't really need more than that and we cover as much ground spraying at 50psi as we do running at 150 when we are spraying trees.
  3. Turboguy

    Turboguy LawnSite Bronze Member
    Messages: 1,972

    There are a lot of people here who know a lot more than I do about compost tea but I am doing my best to learn all I can. I do know a lot about sprayers.

    As far as too little pressure as long as you have enough to pump the CT through the lines and apply it I can't think of a single reason that low pressure would be a problem.

    Some of the people here who have worked a lot with it and really paid attention to what was coming out the end seem to feel that about 70 psi is won't cause a problem for the microorganisms but seem to feel around 85 psi you will see a marked decrease in live microorganisms.

    To me that all makes sense. I am sure if someone were putting a few hundred psi on me I wouldn't feel too chipper after.

    As far as sprayer pumps go most turf sprayers are designed to pump materials that are not alive. I would not even consider a roller pump. Using something unrelated to spraying to illustrate, the action a roller pump uses to pump is similar to trying to roll out dough with a roller. It uses a rolling action to create the pressure. It is also less forgiving of any solids in the material it is spraying.

    My top choice would be a centrifugal pump because it has wide open passages and is far more gentile to the material it is pumping. To me a diaphragm pump is in the acceptable range but not as desirable as a centrifugal. Diaphragm pumps can put out 550 psi so you have to be more careful about the pressure, there is a bit more heat and a bit more physical contact. A diaphragm pump will work and used with care won't be harmful to the CT but to me the number one choice would be a centrifugal.

    To me you should be running at no higher pressure than you need to get the job done. If you are pumping through 300 feet of hose it will likely take 40-50 psi to do that so if I were doing it I would try to stay in the 40-75 range.
  4. RLawns

    RLawns LawnSite Member
    Messages: 42

    I have a jet agitated hydro seeder would that work to spray compost tea? perhaps change the nozzle. Also do you need to keep the tank agitated or would the constant moved kill the organisms?
  5. Turboguy

    Turboguy LawnSite Bronze Member
    Messages: 1,972

    It will work fine for spraying compost tea. You might want to go to a different nozzle. I will pm you with some nozzle suggestions. The recirculation won't hurt the tea.

    You can also use your unit for hydro feeding if you ever want to and have a high qulaity compost. You might be surprised how much compost you can put in and how fast and easy it is. There are some posts by Barefoot James talking about this a little and if this is of any interest to you you can probably find them pretty easily.
  6. Tim Wilson

    Tim Wilson LawnSite Senior Member
    Messages: 795

    I was actually going to start a thread on this today. I know very little about spraying rigs but one of my brewer customers brought to my attention two days ago that all sprayers on the market recirculate (agitate) into the tank when the applicator is not engaged. This is simply a means of releasing pressure on the line so it does not blow the lines or pump.

    This is NOT good for the microbes in compost tea, especially fungal hyphae. I cannot believe that companies professing to know compost tea and microbial horticulture are selling these for CT application.

    We use a homemade rig on the farm and I do have some ideas to create a viable commercial alternative but this will probably take some time during the summer months. It will be electric (operated by 12 volts).

    As for the best pumps to use, the fellow who recommended centrifugal (with impellers) under 80 PSI is spot on. You want a high volume low pressure centrifugal pump.
  7. Turboguy

    Turboguy LawnSite Bronze Member
    Messages: 1,972


    Tim brought up a good point that I forgot to mention in my previous post. Using your hydro seeding unit will work great but run it with your agitation valve closed about 3/4 of the way. It will be enough so there is no damage and will minimize the flow going back into the tank. You can also run your engine RPM at about 1/2 throttle or so and minimize the material going back into the tank.
    Last edited: Apr 2, 2009
  8. Tim Wilson

    Tim Wilson LawnSite Senior Member
    Messages: 795

    According to James, these recirculation jets can be shut right off but I don't know if there is any potential damage to the pump, if left running with no flow. The impellers are obviously going to be still turning.

    My idea includes a pump which turns off and on as the applicator valve is closed and opened.
  9. JDUtah

    JDUtah LawnSite Silver Member
    from UT
    Messages: 2,636


    Hey I am ignorant here. I plan to eventually use some hydro-feeding techniques. Question for you. The jet agitation in a hydroseeder SEEMS to be fairly similar to the agitation in your microbulator IF the hydroseeder is adjusted to use the right nozzles and recirculating volume.

    The question is, does the agitation in your microbulator effect the fungi?

    Then for TurboTurf... do you think one of your units can be modified to perform similar (as far as agitation goes) to a microbulator?

    Sorry, one more question Tim. I have heard people argue that the agitation form bubbles alone in a highly aerified CT brewer can harm the fungi.. I have heard others say that this is a none issue. What have you observed?
  10. dishboy

    dishboy LawnSite Fanatic
    from zone 6
    Messages: 6,161

    Will a electric pump like this be OK for not causing damage to CT?

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