Orchard sprayers 101

One piece of equipment I need to get is a sprayer. Unfortunately I don't know much about them as I've never had cause to have one. What features do I need to look for to spray holistic sprays, such as pump, GPM, agitators? What do I need to avoid? What size should I consider?

Perhaps you could tell us what you have, what you like about it, what you don't like, or wish you had done differently. Your personal experiences would be helpful.

As for myself, I'm leaning towards a Rears sprayer, mostly because they are somewhat local (West Coast) and very popular here in the Okanogan. I'm not sure on size, I have nine acres at present, but do plan on thinning out some trees. I thought 50 gallons would be too small and was leaning towards 100 in a tow behind. I spoke with a dealer and he said 100 gallon tow behinds are rare, either use a three point 100 or go larger. I'm not sure my Kubota 2230 would lift that, and my Kubota M7040 is too large to drive through the trees. He quoted a 50' hose, I'd really like to go longer. All I really know is that I had better get it together quickly as I can't wait until I need it and be told I have to wait several weeks.

Any advice and experiences would be greatly appreciated.

Washington Okanogan Valley
Zone 6b

Please describe your orchard. Size of trees, layout, density, topography, etc. Thanks, Mike

Mike Biltonen, Know Your Roots
Zone 5b in New York

Mike, I posted a description of my orchard in my introduction thread 'Who is that noob asking dumb questions?' in the Just Talk section. Unfortunately the picture didn't upload, but the best description I could come up with was "My orchard comprises about 9 acres. Counting blocks and doing some math I estimated it has approximately 1500 trees. Topography is mostly flat, I do have some trees on slope. Rows are about 20 feet apart, trees about 10 feet apart in the row. Height is about 20 feet."

I think I got the picture to work. It looks like a broken link, but if you click on URL it takes you there.

Washington Okanogan Valley
Zone 6b



Edited 1 time(s). Last edit at 01/12/2021 05:47AM by James Smith.

Hey James, we have a Rears 50 tow behind for about 3 acres of trees (close to 300 semi-standard) I think a 50 might be too small for you, you would have to make a lot of trips to re-fill. When I'm spraying, I just want to get it done, not making a bunch of trips to remix and fill the tank. We tow ours with an RTV, takes 2 people, one driving and one standing in the back/dump bed spraying. 2 of our blocks we can't drive through so the 100' hose with battery powered reel is essential for us to reach every tree. Ours has seen 4 seasons now, the only issue being the trigger handle now needs to be repaired/replaced.

Vista Ridge Orchard
Zone 8a in Washington
235 Cider and heritage apple trees, 72 varieties,

Hello Karen, thanks for your response! How many tank fills does it take for you to complete your orchard? I spoke with Jeff Rear and am waiting for an email with more information from him. He is suggesting that if I can get by with a 125' hose I can get a spring loaded reel. I will be culling out lots of trees, and, what's the word Michael used, topworking, many of them. Even with that I'm leaning towards a 100 gallon tank.

Washington Okanogan Valley
Zone 6b

Hi Jeff, it takes 2.5 to 3 tank full for our orchards and that is slowly increasing as the young trees grow and get bigger canopies. The size nozzle makes a huge difference in how much sprays applied and I tend to use a bit bigger size to ensure good coverage. (runoff) Our sprayer handgun came with different nozzle tip inserts so we can change the droplet size/spray amount..

Vista Ridge Orchard
Zone 8a in Washington
235 Cider and heritage apple trees, 72 varieties,

The first thing to think about when buying a sprayer is how much water is needed to cover the trees. The first step in this process is called Tree Row Volume calculations. Given what you have told us about your trees (10x20x20), the calculations tell me you have 435 gallons per acre (GPA) trees when sprayed full dilute (to run off). However, since trees vary in terms of how much foliage you have at any given time of the year, there is a Stage of Growth Factor (SOGF) that is used to modify the TRV calculation for the amount of foliage. So at formant that number is 0.7, at tight cluster 0.8, at petal 0.9, and at first cover (full canopy) 1.0. This means that at dormant you would need 305 gpa for full dilute, 348 gpa at tight cluster, 392 at petal fall, and 435 at first cover. These number can be modified further for concentrate spraying. If you are spraying what’s called 2X, then the volume of water needed is cut in half, or for 4X it is cut to 25% of the original volume. So, for 2X at tight cluster would be ~175 gpa and for 4X that would be 87 gpa. Of course, there are practical implications, and you’ll need make sure that you also consider spray conditions – wind, rain, sun, etc – when using concentrate spraying. That said, if you needed 175 gpa x 9 acres = 1575 total gallons/400 gallon sprayer = 3.9 tanks total. I am not quite sure why you say the 7040 won’t fit through the orchard? It is only 73” wide vs 20’ wide rows. In any event, you would need at least this HP from the tractor to pull a 400 gal, PTO drive Rears sprayer. Your other tractor (2230) is too small for anything other than a small pull behind and that wouldn’t ever have the power to hit the tops of the trees or cover the canopy. You could try and hose and reel, but this doesn’t really change the volume of water needed to cover the trees in full canopy. So, this may be more technical than you were looking for. Hopefully this is useful. I would suggest a 300-400 gal PTO driven sprayer (pull behind) that you can use with your 7040 (if you can figure out how to get it through the orchard). Let me know if there is anything else I can help with on this or if I missed something that’s critical to your decision making process.

Mike Biltonen, Know Your Roots
Zone 5b in New York

Thanks Mike, very helpful and useful information that I'm certain will be appreciated by future readers. I Googled 'Tree Row Volume calculations' and found it interesting. So the formula is tree height times tree width time row spacing. I got out a tape and measured the trees. I was way off on my height guesstimate, they are only about 12-14 feet tall. Widths are a bit trickier. In the rows the trees are touching (couldn't throw a piece of paper between them, much less a cow) so they are ten feet wide there, however many are growing further out in the rows, some even nearly touching, which is why I can't drive the M7040, and it's canopy, down the rows. I have way too many trees for me to care for alone, so I will be removing quite a few, perhaps even over half. Other factors are 1. I don't want to use an air blast. I watched Jose wearing his rain suit and respirator literally taking a shower in the spray. It may sound stupid, but I would rather point a gun at a tree and shoot it and stay relatively dry. 2. Budget. I'm willing to spend around $5,000. So it's pretty much come down to two options. The Pull-Tank with a PTO drive, or a Skid-Tank with a Honda engine. Base price is a 100 gallon tank, but for only $200 more I can get a 150 gallon tank, and for another $200 I can get a 200 gallon tank. The next jump is a 300 gallon tank, but that adds another $1000. So the 100 fits the budget, 200 stretches it a bit, 300 is a deal breaker. But then I had an idea, why not ask Jose how much he used? His English is poor, my Spanish is only a small bit better, but I understood him to say his sprayer is 400 gallons and he would use 2-3 fills to cover the entire orchard. So now I'm down to choosing whether to use the tractor to power it, or its own motor.

Thanks Karen for your input. I do believe the Nifty Fifty would be require too many fills. However the dealer has one sitting there now, whereas the only Pull-Tank they have is 300 gallons. I'll have to wait about three months to have a smaller Pull-Tank built.

Washington Okanogan Valley
Zone 6b