Why? I would think slow release granular fertilizer would work the best.

Price. Granular fertilizer like Turf Builder for 5 acres of lawn is expensive to apply.

Okay, then let's talk about 5 acres of grass. Nothing, NOTHING is less interesting and more work than 5 acres of lawn. When was the last time you opened "Better Homes and Gardens" to see a 5-acre lawn? Never. Please consider adding hedges, arbors, orchards, rose garden, zen garden, vineyard, walking paths, gazebos, decks, patios, statuary, barbecue/picnic facilities, parcours, fencing, gazing balls, bowling balls, or anything to break up the monotony of 5 acres of grass.

I know you won't do all that but I was trying to make a point. Since you already have the tractor you are hot to make it work. Nothing is going to be cheap unless you want to make your own compost tea and spray that. One thing I've seen done up here in the Texas Panhandle (where I work, not live) is they spray molasses at a rate of one gallon per acre about 4 times per year. Molasses is cheap. They get it at the farmer's co-op for about $0.10 per pound. It's 11 pounds per gallon so a gallon costs $1.10. Molasses is not well known as a fertilizer but it is used as part of a soil building system that doesn't necessarily apply to you. I'd spray it if I had the tractor, though.

As for getting the product out there, unless you want to take days spraying it, you should use your ag sprayer with a #20 nozzle (giant hole). Weld a stainless steel plate angled at 45 degrees to the spray direction under the nozzle exit. The liquid hitting the steel will form a wide spread pattern out behind the tractor. I know a lady who sprays 200 gallons per day with that arrangement. She has 500 acres to spray and needs to get it all sprayed 4 times per year. For your small acreage you could be finished in an hour easily. (Notice how your 5 acres went from immensely huge to small in just a paragraph - it depends on the scale of what you're talking about ;-) )

You also might look at the dry fertilizers from Lesco. That's what the large scale professionals use. They might have liquid products but the pros use granular. Check with your local feed store to see what the others with 5 acres of grass are using.

twosevenright said:
Price. Granular fertilizer like Turf Builder for 5 acres of lawn is expensive to apply

I am not sure I believe you said that? If price is your main issue, then you would never even consider a liquid fertilizer because it can cost up to 100 time more than granular when applied at a pound for pound rate.

For example using a slow release 39-0-0 granular in 50 lb sacks which is the highest cost per volume a consumer can use runs about $25 per bag and will cover 20,000/ft2, so it takes 2 bags to cover 1 acre or $50 per acre to apply 1 pound of nitrogen. That will last 30 to 60 days. Buy it in bulk form and it is even less expensive.

Use one of the Ag grade liquids in bulk like Nutra-Flow in 50 gallon drums and is applied at a rate of 40 gallons per acre to equal 1 -pound of nitrogen. At a cost of $10 per gallon comes out to $400 per acre and is gone after a couple of rain storms.

See where I am going with this?

twosevenright, the gpa(gallons per acre) rate is determined by nozzle output, swath width and the forward speed of the tractor. The nozzle output is measured by catching and measuring the liquid from it over a measured time period. Let's say 1 gallon in 20 sec. (3 gln./min). The swath is the width of the wetted strip as the rig travels. The swath is best measured by spraying water only on a parking lot or similar surface. Be sure that all the nozzles are in the same plane and that there is only enough overlap as recommended by the nozzle manufacturer. To calibrate the rig, you will need to spray a length of surface at a constant speed (hand throttle set; appropriate gear selected). Time the duration of this exercise as accurately as you can. Let us say that you have sprayed 500ft. in 30 sec., that the swath is 10ft wide. (a boom with 4 nozzles @ 2' 6" effective width).
You have sprayed 5000 sq.ft. (500 x 10) or 1/8ac. (40000 sq.ft. per acre because I am lazy today). The 4 nozzles have delivered 6 gallons. (4 x 3gpm. each) for the timed run (half a minute). For this exercise the application rate has been 6 gallons over 1/8 ac. or 48 gallons per acre. (I am tempted to add QED). You know the quantity and analysis of the concentrate; you can calculate the lb nitrogen per thousand sq.ft.