pics below of my makeshift sprayer setup, ready to roll with some Trimec to bludgeon the spring weeds.
it's not quite a completely "home built" system. i started off using a generic FIMCO setup (w/ 25 gallon tank), which came stock with a hand sprayer (wand) (see pics below). the FIMCO tank was simply set on my carryall. the pump itself is powered by the 12Vdc accessory outlet below the operator seat; this feature is stock on the BX series. i added more pressure hose, so my wife could slowly drive the tractor and i would walk around behind the rig and dispense herbicide using the sprayer wand. i should mention that the area to be treated is just north of an acre. basically with this setup i had a 25 gallon capacity hand sprayer, and i was trying to treat an acre+ of turfgrass twice a year. this "hand spray" approach was sorta effective on the weeds but a general pain in the ***, plus the uniformity of application is always in question. maybe the best feature was that with the handheld wand you can get fairly close to ornamentals and such.
i started looking around for bits and pieces to convert the hand system to a nozzle system. in principle this means finding a boom assembly that has the coverage desired AND has a flow rate (at a given pressure) which the pump can handle. note that this conversion is not exactly straightforward because the pump setup used for a hand system (demand type: pressure low turn-on / high turn-off) is not the same as used for a spray system (constant pressure with bleed recirculation). in my case it worked out ok that i had a pressure turn-on/turn-off pump arrangement, it took some experimentation initially but the system runs at a nice even 30psi during spray operation. note: too little pressure and you will get sputtering; too much pressure and you will atomize the herbicide-laden liquid into a fine cloud which will blow all over the place.
my carry-all deck does not come up high enough for the Teejet nozzles, which have a specified 18" height above terrain for proper spray coverage. i was going to carpenter-up some sort of base for the tank to sit on, which in turn would be placed on the carry-all, but then i got to thinking i could just use the
ballast box as the tank carrier. a pair of carefully cut and mounted scrap 2x4's allow the tank to "seat" in the top of the empty ballast box, and once it's filled with water and herbicide the tank is not going anywhere.
i stumbled around in the sprayer aisle at Tractor Supply for a while and bought some more pressure hose, fittings, and an poly 90 degree shutoff valve. the pressure output of the tank, instead of going to the hand wand, is carried up to near the operator station, where the control valve is located, and then back to the spray heads. (note: try to keep the piped "distance" to the spray jets symmetrical, otherwise you get pressure imbalance).
so, to prepare for spraying, you fill the tank 2/3rds with water, put the herbicide in, and then fill the remaining third. during all this you run the pressure pump in "recirculate mode", which draws in liquid from the bottom of the tank and pumps it right back into the top of the tank (this is a stock function of the FIMCO pump manifold setup). after about 10 minutes of recirculating you are ready to roll.
position the tractor where you want to start, twist the control valve 90 degrees to start herbicide flow, and get moving ASAP. do not stop the tractor without first turning the control valve off, or you will deposit A LOT of herbicide in one place.
i want to point out a few things:
1) before your first spray job, it is first necessary to determine how much solution you are applying at a given speed. this is best done using a tank full of water and a known distance (i measured using GPS). fill the tank right to the brim, and close the top. make a run. using a kitchen measuring cup, refill the tank right to the brim. now figure out, at a given tractor speed (RPM and range), how much fluid is going out, and therefore the application rate. the spray head folks, Teejet in this case, provide tables for every one of their nozzles, in terms of flow rate (GPM) vs PSI. don't forget to multiply times the number of nozzles.
2) selective herbicides for turfgrass (such as 2,4-D) work by attacking biological aspects of annual and perennial weeds which differ from perennial turfgrass. however, these very same herbicides can and will absolutely demolish plants that are not weeds -- such as tomatoes or lettuce or roses or myrtle or whatever expensive thing your wife just planted. so when spraying in a residential environment you have to be extraordinarily careful about where the spray is applied and just as importantly where the wind is carrying it. for this reason, calm days and "just enough" system pressure are critical aspects. when i first used my makeshift sprayer i tested coverage in the driveway using straight water, and then used a piece of PVC conduit as a "guide" for my first go around. this guide would prevent my wife from subsequently killing me for killing all of her flowers. yes, it looked ghetto as **** but i'm still alive today.
3) don't spray when it's very hot. the turfgrass is already under stress during these conditions. even though the herbicide is "selective" you can still kill huge swaths of turfgrass by applying an otherwise "safe" herbicide when it is 100'F outside.
4) you need a TON more water to apply fertilizer vs herbicide. so much more that it makes it impractical for me. i apply granular fertilizer (using a broadcast spreader) and spray for weeds (using my makeshift setup). this is the easiest approach.
ps
here is the FIMCO sprayer i started life with. 5 years in the pump and rest of the bits are still going strong.
Spot Sprayer, 25 Gallon Sprayer, Sprayer, Fimco Sprayer | Agri Supply, 32996
also see
Agricultural Sprayers, Backpack Sprayer | Agri Supply ATV Sprayer
and
Standard Trailer Sprayer-Two Nozzle Trailer Sprayer | Agri Supply #32995
wrooster
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