The Check Isn't the Deduction
Every December a farmer calls me feeling good about a check he just wrote to the co-op. Big number. Next year's seed, fertilizer, maybe a tank of fuel, all bought before the 31st. He's sure he just turned a tax bill into a deduction. Sometimes he did. Sometimes he bought himself a problem that doesn't surface until April.
Here's the part people get backwards. Yes, a cash basis farmer can deduct prepaid seed, feed, fertilizer, and chemicals in the year you pay for them, even though you won't put them in the ground until the next crop. But the write off does not come from the money leaving your account. It comes from two things the IRS actually looks at: whether you bought goods or just parked cash, and whether the prepaid amount stays under a line most operators have never heard of. Clear both and the strategy still works. Miss either and the deduction gets shoved into next year — or denied.
So writing the check isn't the work. Spending money is the easy part — hell, any operation can move cash out the door in December. The work is the structure around it. Two gates stand between you and the deduction.
Gate 1: You have to buy something, not park money
The IRS lets you deduct a prepayment for supplies only when three things are true at once. This isn't new and it isn't a gray area — it traces back to a 1979 ruling that's still how these get judged.
First, it has to be a real purchase, not a deposit. That's the one auditors lean on hardest. The invoice needs to nail down a specific quantity, a specific product, and a fixed price. A slip that says "Fertilizer — $30,000" is not a purchase. It's a coin flip you'll probably lose. And you can't reserve a right to a refund or to swap the money for something else later. The minute it looks like you could get your cash back, it's a deposit, and a deposit buys you no deduction.
Second, there has to be a business reason beyond the tax savings. This is easy to clear if you're honest about why farmers prepay in the first place: locking in a price before it climbs, or making sure the product is actually there when you need it in the spring. Those are real reasons. "My accountant said to spend money" is not.
Third, the deduction can't badly distort your income — pulling a giant expense forward in a way that has nothing to do with how you really operate. For most working farms that prepay every year as a matter of course, this isn't a problem. For the operation that's never prepaid a dime and suddenly dumps a year of income into December inputs, it can be.
Get those three right and you're through the first gate. Most of the time, that comes down to one thing: get a real invoice with real numbers on it, and don't let the co-op write it loose.
Gate 2: The 50% line
This is the gate that surprises people, because nobody mentions it until it costs them.
Your deduction for prepaid supplies you haven't used yet can't be more than half of your other deductible farm expenses for the year. Everything else on your Schedule F counts toward that other half — labor, rent, repairs, depreciation, the works — but the prepaid supplies themselves don't. Whatever you prepay above that 50% mark doesn't vanish. It just waits and deducts in the year you actually use it.
A number makes it concrete. Say your other deductible farm expenses for the year add up to $400,000. The most you can write off in prepaid supplies this year is half of that — $200,000. Prepay $300,000 of inputs in December and $100,000 of it does nothing for you this year. It carries to next year and deducts when the seed goes in the ground.
That's not the end of the world — you still get the deduction, just later. But if the whole point was to knock down this year's income, finding out in April that a third of your prepay slid into next year is a rough surprise.
There are two ways out of the 50% cap, and you only need one of them. They're open to a "farm-related taxpayer" — broadly, someone whose home is on the farm, whose main job is farming, or a family member of someone who fits. If that's you, you can deduct the full prepaid amount when either: the year ran over 50% because of an unusual, one-off change in how you operated; or your prepaids over the previous three years averaged under 50% of your other expenses. Steady operators who prepay normally most years tend to land inside that three-year history without trying. The farmer who goes big exactly once is the one who gets caught.
What this actually means before you write the check
None of this should scare you off prepaying. Done right, it's one of the oldest and cleanest tools a cash-basis farmer has for smoothing income between a fat year and a lean one. It just rewards the operator who sets it up on purpose instead of in a panic.
A few things to do and they're not complicated:
Get an invoice that states the quantity, the product, and the price. Make the co-op write it tight. "Seed and chem, $X" is the version that fails.
Don't sign anything that lets you claw the money back or trade it for something else. That language turns your purchase into a deposit.
Run the 50% math before you write the check, not after. Add up your other farm expenses for the year, take half, and know your ceiling. If you're going over, know which exception you're leaning on.
Have a reason you'd be comfortable saying out loud — locking price, securing supply. You almost certainly have one. Say it.
Talk to whoever does your return in November, not in March. The deduction is set by what you do before December 31. Once the year closes, there's nothing left to plan.
How the cap and the exceptions land depends on your specific operation and your numbers, so this is the general shape of the rules, not a verdict on your return. That's exactly the conversation worth having before year-end.
The bottom line
The check feels like the work. The check is the easy part.
The deduction lives in the invoice, the math, and the reason — and that's the part most people skip.
If you're running an operation big enough that a December decision moves real money, you shouldn't be guessing at it in the truck on the 30th. That's the kind of planning we do. Apply to work with us → https://steinkeandcompany.com/application
