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Agri-Fab Spreader Settings: Tow-Behind & Push Models

Agri-Fab owns the big-lawn niche: 85–130 lb tow-behind hoppers pulled behind a lawn tractor, plus push broadcast models. Big-lawn spreading changes the settings problem in two ways most charts ignore — ground speed replaces walking pace as the dominant variable, and hopper planning (fills per lawn, pounds carried) becomes real logistics. This page covers the 1–10 dial, speed effects, and a setting + hopper coverage calculator built for acreage.

The tow-behind golden rule:

The dial controls flow per second; your tractor controls square feet per second. Pick one steady gear (~3 mph), calibrate at that speed, and never chase rate changes with the throttle.

Jump to: Calculator · The 1–10 dial · Ground speed · Settings chart · FAQ

Walk-behind spreader instead? Scotts · EarthWay · Any brand by rate: cross-brand converter

Calculator

Agri-Fab Setting & Hopper Coverage Calculator

Rate in → starting dial out, plus how far one hopper goes and how many fills your lawn takes.

The Agri-Fab 1–10 dial and the rate matrix

Agri-Fab broadcast models use a numbered flow-control dial — typically 1 to 10 with half steps — attached to a rate-adjustment stop so you can return to a calibrated position repeatedly. Each model's manual includes a rate-setting matrix (product class × rate → suggested number) along with Agri-Fab's calibration procedure: compute the bag's rate per 1,000 sq ft, run a measured test, compare, adjust the stop, repeat. That "set the stop, not just the dial" detail is the feature worth using — it's what makes season-to-season repeatability possible on a spreader that lives in a shed.

Because Agri-Fab has sold dozens of hopper sizes across decades, the matrix in your model's manual (model number is on the hopper decal or frame; manuals are on Agri-Fab's support site) beats any generic chart — including the one below, which is a starting-point summary for common current models.

Ground speed: the variable that outranks the dial

Every spreader dispenses per unit time, but walking pace only varies so much — a tractor's does. Tow at 6 mph instead of 3 and you cover twice the ground per second at the same flow: the delivered rate halves without the dial moving. That swamps the difference between adjacent dial numbers, which is why tow-behind calibration is really speed-plus-dial calibration: pick the gear you'll actually use (a steady ~3 mph equivalent), run the test-strip check at that speed, and treat gear + dial as one setting. Slowing down for turns? Close the gate — towed spreaders dump heavily through slow turns, which is where the classic "burned circles at the row ends" pattern comes from with synthetics.

Agri-Fab settings chart (broadcast models)

Starting points by rate for current push and tow-behind broadcast models at a steady ~3 mph. Your model's manual matrix supersedes this table.

Rate (lbs/1,000 sq ft) Typical products Push broadcast Tow-behind
2 Light fertilizers, pre-emergents 3 3
3 Standard synthetic fertilizers 4 4
4 Fertilizer + pre-emergent combos 5 5
5 Heavier synthetic rates 6 6
6.5+ Starter fertilizers, organics 7 — or half × 2 passes 7 — or half × 2 passes
12.8 Milorganite Classic 6.5 (half × 2 passes) 6.5 (half × 2 passes)

Push and tow columns are close on the dial but differ in practice through travel speed — calibrate each unit at its real speed. Sources: Agri-Fab model manuals; Milorganite row from Milorganite's settings pages.

Big-lawn gear

Upgrading from walk-behind? A tow-behind broadcast spreader↗ pays for itself in time on anything over ~15,000 sq ft. Whichever hopper you run, a digital scale↗ for test-strip weighing is what turns the chart above into your unit's real numbers.

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FAQ

What do Agri-Fab spreader settings mean?

A brand-specific 1–10 flow-control dial setting the gate opening — no relationship to Scotts, EarthWay, or any other scale. Each model's manual has a rate matrix as the starting point; see the dial section.

Does towing speed change the application rate?

Yes — within normal ranges, more than the dial does. Same flow at double the speed = half the rate per square foot. Calibrate at your actual gear and hold it — details above.

Are settings the same for push and tow-behind models?

The numbers run close, but each model has its own manual matrix, and the travel-speed difference (walking vs towing) shifts delivered rate independently. Treat them separately and calibrate each.

How much lawn does one hopper cover?

Hopper lbs ÷ rate × 1,000: a 130 lb hopper at 3 lbs/1,000 covers ~43,000 sq ft; the same hopper at Milorganite's 12.8 lbs/1,000 covers only ~10,000. The calculator does this per fill and per lawn.

Where can I find the chart for my exact model?

Agri-Fab's support site hosts manuals with per-model rate matrices — search by the model number on the hopper decal or frame. Your model's manual supersedes generic charts, including this page's.

Related settings & tools

Important note

Settings on this page summarize Agri-Fab manual matrices, which Agri-Fab describes as guides subject to material characteristics, travel speed, and ground surface. Your model's manual and the product label supersede this page. Calibrate at your real travel speed before treating the whole property.