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Growin’ Green

Steps To Accurate Sprayer Calibration

By Brent Gray


Accurate herbicide applications are essential for turf safety and good weed control efficacy. Calibrating sprayer solution volume involves selecting the proper nozzles, spraying pressure, and speed of travel. There are several different ways to accurately calibrate a sprayer, but the simplest is the 1/128th acre (340 sq.ft.) method. Regardless of the number of nozzles on the boom the spray collected from a single nozzle measured in ounces directly converts to gallons per acre. The ounces collected from 1/128th of an acre will equal gallons of solution per acre due to the fact there are 128 ounces in a gallon.
Follow the 10 easy steps below to avoid needless chemical waste, improper application, and potential turf injury.
1. Fill sprayer with water. Use only clean water to calibrate sprayer.
2. Whatever the type of sprayer tips you use, be sure they are all the same type and nozzle size. To check the uniformity of all nozzles on the boom, collect the spray from each nozzle for exactly one minute.  If the flow rate of any spray tip is 10% greater or less than that of the others, replace it.
3. Determine the distance (in feet) between nozzles on the spray boom and divide into 340 to obtain distance to travel in feet.  Example: 18 inches between nozzles is 1.5 feet divided into 340 equals 227 feet travel distance (18/12 = 1.5 then  340/1.5 = 227).
4. Measure the distance to travel (in feet) and flag it for easy visibility.
5. Drive the flagged distance at an acceptable spraying speed with the sprayer on. Make note of the engine RPM’s, and most importantly, record the seconds it takes to travel the measured distance between the two flags. Be sure to maintain a uniform speed within the flagged distance.
6. Park the tractor/spray-er, set the brakes, but keep the engine RPM’s at the same setting used to drive the test course and make any final sprayer pressure adjustments (this will vary with the type of spray tips you use and the gallons per minute you wish to spray through them).
7. Using a plastic measuring container that is marked in ounces, collect the water sprayed from one nozzle for the same amount of time it took to drive the flagged distance.
8. The amount of water collected in ounces will equal the gallons applied per acre.
9. Be sure to read all product labels for proper application information, use rates, etc.
10. While making applications maintain continuous engine RPM’s and ground speed used in test run.
For a back-pack or other single nozzle sprayers this same method will still work.  Simply determine the width of the spray pattern to get the distance (Ex: 20”/12 =1.66 then 340/1.66 = 204 ft.).  Or, fill the sprayer completely with water then spray an area equal to 340 sq. ft. (20’ x 17’).  The ounces of water required to refill the sprayer completely will equal gallons per acre.
 
Planting Time For Trees and Shrubs

Continue to plant dormant container-grown, balled and burlapped or bare-root trees and shrubs during February.  Fruit trees and berry plants will be arriving in nurseries soon.  Choose your selection early and get them in the ground for the greatest chance of success.
Plant nut trees like pecan, walnut and Chinese chestnut. Remember to plant two or three chestnuts so they can cross-pollinate.  Also, select at least two cultivars of rabbiteye blueberries to plant so that you get good pollination and fruit set.
 
Pruning Tips
Pruning of evergreen shrubs (other than those like azaleas that bloom in the spring) should be done now or any time before spring growth begins. If no pruning is necessary on your trees and shrubs, but there are some obvious cold-damaged stems, resist the temptation to prune these winterkilled branches until March or April when you can determine exactly the true extent of winter damage.
Pruning of established fruit trees can be done now and any time before spring bud break.  Be careful not to remove fruiting spurs when pruning apples, plums and pears. Prune muscadine and bunch grapes.
 
Vegetables

Onion sets are available in garden centers now. An onion set is a small onion bulb which was dug up and stored last Fall. The bulbing response has already been initiated so the set will put out roots and leaves and grow a new onion plant with a little head start on the bulb sizing. Plant sets shallowly and be sure to keep them moist. Choose a short day variety for best production.
Also in some garden centers are multiplying onions. These are used for green onion production. The good thing about multiplying onions is that you only plant once since the plant will reproduce itself by making more bulbs.
Be sure to remove or turn under the cabbage and broccoli plants from the garden after you finish harvest. The old leaves and stems are food for several insects and can help build the population to damaging levels.
Cloudy days make seedling grow taller. If your tomato and pepper plants look like they are stretching, you can help make them stronger by petting them! Research has shown that gently stroking the small plants in the same direction at least twenty times a day will make shorter, stronger stems. Your plants can’t purr and give you an  immediate response, but shorter plants are less easily damaged when transplanting.

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