Spreader Calibration

This is a fool proof way to accurately spread seed or granular fertilizer using any mechanical spreader.

There are two types of mechanical spreaders; broadcast spreaders and drop spreaders. Broadcast spreaders fling material out in front of the moving spreader while drop spreaders drop material straight down between the wheels of the spreader.  These calibration instructions apply to both types of spreaders. 

These instructions are generic because there are too many different spreaders on the market to provide accurate settings for every different seed or fertilizer in every spreader model. Follow these instructions and you will never make the mistake of running out of product before you cover the entire lawn. 

Step 1: Measure the area to be covered.  For a yard with square corners, multiply length times width in feet to determine the square footage.

For lawns which do not have square corners estimate the dimensions of a square area that approximates the area of your lawn.  It doesn't have to be exact, so round up  to the next highest 1,000 sq. ft. to be safe.

Step 2: Weigh out the proper amount of seed or fertilizer to cover the area at the recommended application rate.  For example, if your lawn is approximately 8,000 sq. ft. and the application rate for Kinder blend Turf Maximizer fertilizer is 5 lbs./1,000 sq. ft., you need to apply 40 lbs. of fertilizer (5 X 8=40).  In contrast, if you are planting SS1100 bluegrass blend to the same area at a recommended seeding rate of 2 lbs. per 1,000 sq. ft., you need only 16 lbs. of seed (2 X 8=16). 

Step 3.  Divide the material to be spread into two equal parts.  You can do this using a bathroom scale or visually dividing the product into two equal piles.

Step 4: Load the first half into your spreader and put the other half in your garage.  Pretend the second half doesn't exist!

Step 5: Set your spreader 20% open, 80% closed.  For example, if the spreader scale is 1-20, set the opening to 4 (.2 X 20=4).  For a scale of 1-10, set the opening on 2; For 1-100, set it on 20, etc.  This is just a starting point.  Seeds vary in size so you will invariably need to adjust the setting as you go.

(Note:  for extremely small seeds such as bentgrass, bulk up your seed by mixing it with dry play sand before spreading).

Step 6: Start walking and spreading.  Walk parallel to the street. 

The objective is to spread the material in the hopper over the entire lawn.  Watch the hopper.  If you get half way through the lawn and less than half the product remains in the hopper, stop and reduce the setting.  If on the other hand, you're half way through and 3/4 of the material remains in the hopper, that 's okay.  Just keep walking and go over the lawn an extra time in that direction.  If the seed or fertilizer is emptying out way to slow, stop and open the spreader setting wider.  Empty the hopper taking as many trips across the lawn in that direction as necessary. 

Step 7:  Reload the hopper with the other half of the product from your garage.  Adjust the spreader setting up or down according to your experience with the first pass and begin spreading in a direction perpendicular to the first direction.  Cover the entire again in one or more passes.

Step 8: Remember the spreader setting on the second load for future reference when spreading the same seed or fertilizer with that spreader.

Note: Always cover the entire lawn in two perpendicular directions to prevent skips and stripes.