Well, if the spreader was fully engaged and the grass wasn't overly wet (plugging the outer holes) I'd say you have a calibration problem. In the olden days thay had a gage to set the spreader by. At least it wasn't the other way and too much got on the lawn. CAn you get help from Scotts? Or I would bump it up a notch and hopefully you can figure what the setting variance actually is.

I have the same model and wonder about its accuracy also. Since you only got 1/3 down, it gives you something to start from.

You can either estimate what the opening would be to get the remaining 2/3 down in one pass or repeat your current setting 2 more times.

I'd probably go with the current setting as it could release a different amount on your next passes. You problaby know that the dry product manufacturer estimates the setting based on the granule size and the amount of product needed per square foot. So if I need 40lbs of lime per 4000'sf I think the setting is 8 or something like that. For your fertilizer, I would guess it is 40lbs per 5000'sf. Smaller granule, etc. You could figure out your spreader by rigging it up in a fixed station, turning the wheels at a comfortable walking pace and collecting the product. You would have to know how wide the swath is of the spreader but you get the idea. Probably way more than you want to do. I know I have not done it :). I basically estimate how much product I has been put down in one pass and adjust from there. If I had more land to cover, I would not put up with it though. I would want something that put down what it said it does.

You said you calibrated it first. My Scott's says to set it to "6" and when you squeeze on the lever the line on the front edge of the shutoff bar should be even with the calibration line engraved on the bottom of the hopper, if it doesn't you need to adjust the black screw on the lower end of the control wire. Is that what you did to calibrate it?

I always try to use a lot less fertilizer and apply more frequently. I hate having to mow twice a week for a month:-)
I admit I just use straight 21-0-0, which tends to "dissolve" quickly.
BTW, I use a hand broadcast spreader. It's SOOOO much faster.
Open it up wide and crank fast. It covers a swath about 10-12' wide in one pass. Vary your pace for thin or "lush" areas.

Yes metal....that's exactly right.

I sometimes wonder how much speed affects application rate. It seems if you walk too fast the spreader doesn't keep up and you use less fertilizer. They don't really say anything about it in the instructions.

Speed does affect the application at least for broadcast spreaders. As you go faster, you are dropping product from the hopper at about the same rate but you are throwing over a larger area to the sides and you are covering more ground going forward. I have found the opposite if going to slow, much more product per area than I want. I don't think it affects drop spreaders as much.

I wound up walking my front yard (5000 sq. feet) 3 separate times to finally zone in on the right setting. I was really tired and annoyed, but it did teach me what the spreader was (and was not) doing.

Now my back yard was done yesterday. I measured out a proper proportional amount for the back (1875 sq.feet) and set the Accu Green on 7 1/2 instead of the recommended 5 1/2. Now I am getting just the right amount down (in two opposite passes) which is just what I was shooting for.

In my opinion, the Accu Green is a cheaply made spreader that definitely needs to be tested, even if the calibration is right on the mark. The recommended setting for my particular product (Scotts TB w/ Halts) was not even close to what I found worked. I will say that it does spread evenly and I really like the padded handles and on/off lever so I will be keeping it...just don't trust what the bag says without a test for your lawn, walking pace, product etc.

I have an AccuGreen model that's approx 20 - 25 yrs old. The drop rate at the specified setting was approx 1/3 of anticipated. My drop spreader has no calibration mark or cable adjustment near the hopper like the newer models. After reviewing with Scotts, they indicated one should set the adjustment to "6". depress the feed lever and the opening should allow a 9/64" drill bit to pass through the hopper "teeth". Since my model doesn't have a cable adjustment near the hopper, I shimmed the cable by sawing/filing a slot in a small washer sliding it over the cable so the cable tensions more quickly. The washer was super-glued into place after confirming the desired outcome. Fortunately, this fabrication solution approach got me to the 9/64" at a six setting. Hope this helps those who have older AccuGreen drop spreader models.