Reviewed September 2026 against USDA AMS pricing (via farmdoc daily, University of Illinois) and CRU Group tariff analysis.

Try it: Run your own numbers →

Potash (0-0-60 muriate of potash, or MOP) is running $500-$535 per ton at Corn Belt retail as of August-September 2026, and 9-23-30 blends move with it because potash supplies the “30” — the potassium component — in that mix. A 25% U.S. tariff on Canadian potash imports, in effect since March 4, 2025, is the direct cause: Canada supplies roughly 80% of U.S. potash, and CRU Group’s pre-tariff modeling forecast a $65-per-metric-ton Midwest price increase once the tariff took hold. Below is what’s actually in the ground right now, what it costs, and how to check it again next quarter without waiting for someone to write a new article.

Table of Contents

• What is 9-23-30 fertilizer, and what does it cost?
• What does potash do in fertilizer?
• Cost of potash per ton, current and year-over-year
• The potash tariff: what it is and what it did to prices
• Fertilizer costs overall: the other inputs moving with potash
• Calculator: your per-acre potash cost
• Managing input costs without cutting yield
• The current event driving this: how to track it yourself
• Try it: Run your own numbers

What Is 9-23-30 Fertilizer, and What Does It Cost?

9-23-30 is a blended fertilizer: 9% nitrogen (N), 23% phosphate (P₂O₅), 30% potash (K₂O). It’s a common starter or pre-plant blend for corn and soybeans where soil tests show adequate nitrogen reserves but a potassium deficit. There is no single published national retail price for the 9-23-30 blend itself in the USDA AMS series referenced here — blends are custom-mixed by retailers from component ingredients, so pricing is dealer-specific and not tracked as a standalone SKU the way straight urea or MOP are.

What you can do instead is price the components and back into the blend cost. As of the week of August 7, 2026, USDA AMS data reported via farmdoc daily puts diammonium phosphate (DAP, 18-46-0) at $912.22/ton wholesale and MOP (0-0-60) at $500/ton at Corn Belt retail. A 9-23-30 blend draws its phosphate and potash largely from those two products (with a nitrogen source added), so a blend price should track roughly proportional to those component costs — but the only way to get an exact number for your farm is to ask your retailer for a current quote, since blending margins and freight vary by dealer and region.

To get a current 9-23-30 quote yourself: call your local co-op or retailer and ask for a per-ton price on the blend delivered to your farm, then compare it against the component math above. If the quoted price is running well above what DAP and MOP costs would suggest, that’s your negotiating signal.

What Does Potash Do in Fertilizer?

Potash supplies potassium, one of the three macronutrients plants need in the largest quantities (alongside nitrogen and phosphorus). In fertilizer labeling, potash is the “K” in N-P-K, and it’s expressed as K₂O — so a bag labeled 0-0-60 is 60% potassium oxide equivalent by weight, none of which is nitrogen or phosphate.

Specifically, potassium does the following in a growing crop:

• Water regulation: Potassium controls the opening and closing of stomata, the pores that manage water loss and gas exchange in leaves. A potassium-deficient plant wilts faster under drought stress.
• Enzyme activation: More than 60 enzymes involved in plant growth require potassium as an activator, including those governing starch and protein synthesis.
• Disease resistance: Adequate potassium thickens cell walls, which is why potassium-deficient stands are more vulnerable to stalk rot and lodging in corn.
• Yield and grain fill: Potassium moves sugars from leaves to grain and roots during fill. Deficiency shows up as lower test weight and smaller kernels even when nitrogen and phosphorus are adequate.

This is why potash demand doesn’t disappear when prices rise the way discretionary inputs might — it’s a macronutrient with no substitute, which is part of why the tariff-driven price increase discussed below passed through to farmers rather than being absorbed by reduced application.

Cost of Potash Per Ton: Current Figures

Potash pricing depends on which grade and which reporting series you’re looking at. Here’s what’s published, with dates attached so you can judge how current each figure is against whatever you’re reading this next:

The spread between the $487-535 retail range and the $694-744 “asking price” figures reflects different points in the supply chain and different reporting methodologies — asking prices in the AMS Illinois Cost of Production report are typically dealer list prices before regional/volume negotiation, while the Corn Belt retail figures reflect actual transacted averages. Neither is wrong; they’re measuring different things. If you’re budgeting, use the retail-transaction figures ($487-535); if you’re evaluating a specific quote against the ceiling, the asking-price figures are your benchmark.

For the fullest current picture, including how these figures compare against phosphate and nitrogen trends, see farmdoc daily’s Fertilizer and Fuel Prices Higher Heading into Fall 2026 and the ongoing tracker at FertilizerPrice.com’s potash page, both of which update as new USDA AMS data is released — a more reliable path to a fresher number than any static article, including this one.

Potash pricing also moved over the trailing year in a way worth tracking directly: anhydrous ammonia, a bellwether nitrogen input that tends to move with broader fertilizer market sentiment, rose 16% year-over-year from August 2025 to August 2026 according to USDA AMS data reported via farmdoc daily. Potash hasn’t moved at that pace — the March-to-August 2026 shift above is a roughly 3% increase — but it’s moving in the same direction, consistent with the tariff-driven cost floor discussed next.

For deeper background on how these figures compare to the 2025 forecast baseline and the broader pricing trajectory since, see Farmonaut’s 2025 fertilizer price forecast and the follow-up on potash price trends.

The Potash Tariff: What It Is and What It Did to Prices

On March 4, 2025, the U.S. Office of the President imposed a 25% tariff on most Canadian imports, including potash. This mattered more for potash than for almost any other agricultural input because of how concentrated U.S. supply is: the U.S. imports roughly 12 million tonnes of potash from Canada annually, and Canadian potash accounts for approximately 80% of total U.S. potash supply, according to CRU Group’s analysis. There is no comparable domestic substitute at that volume — the U.S. has limited potash reserves (mainly in New Mexico and Utah) and no near-term capacity to replace 80% of national demand.

CRU Group’s pre-tariff forecast modeled a $65-per-metric-ton increase in U.S. Midwest MOP prices by August 2025 compared to February 2025, driven by the tariff cost passing through the supply chain from importer to wholesaler to retailer. Whether that specific $65 figure was fully realized isn’t confirmed in a follow-up publication as of this review — CRU Group’s piece was a forecast, not a retrospective measurement, and no separately published reconciliation of forecast-versus-actual has surfaced in the sources checked for this article. What is measurable is the retail trajectory shown in the table above: $487/ton in March 2026, $500/ton in August 2026, both after the tariff had been in effect for roughly a year.

Two structural facts explain why the tariff pass-through was hard for buyers to avoid:

• Concentration: 80% single-country supply share means there’s no meaningfully diversified alternative sourcing at scale. Buyers can’t simply switch suppliers the way they might with a less concentrated input.
• Inelastic demand: As covered above, potassium has no agronomic substitute — a farmer can delay an application or cut the rate, but can’t replace potash with a different nutrient.

For readers checking whether the tariff rate or scope has changed since this review: tariff policy is set by executive action and subject to change without the lag that price data has, so verify the current rate directly against USTR or Federal Register notices rather than relying on any article’s stated rate as still current.

What Is a “Potash Tariff” in Practical Terms?

For a farmer or buyer, the tariff functions as a line-item cost added at the border on Canadian-origin potash, which is then priced into the delivered cost by importers and wholesalers before it reaches retail. It is not a separate charge visible on a farm invoice — it’s embedded in the retail price per ton already shown above. That’s why the retail figures ($487-535/ton through 2026) are the number that matters for budgeting, not the tariff rate in isolation.

Fertilizer Costs Overall: What’s Moving Alongside Potash

Potash is one leg of a three-input stool. Here’s where the other major fertilizer costs stood as of the same USDA AMS reporting window (week of August 7, 2026, via farmdoc daily):

Anhydrous ammonia and DAP are both running above $900/ton, well ahead of potash’s $500/ton — a reminder that potash, while the input most affected by the specific Canada tariff story, isn’t the largest single line item on most fertilizer budgets. Nitrogen and phosphate sources typically cost more per ton than potash even when potash prices are elevated by tariff effects.

These figures are all from USDA AMS data compiled and published by the University of Illinois’s farmdoc daily service, which updates its fertilizer and fuel price roundup on a rolling basis — the direct source is farmdoc daily’s fertilizer and fuel pricing report. Check that page directly for the current week’s figures rather than treating the August 2026 numbers above as permanent.

For background on U.S. domestic fertilizer production capacity — relevant to why the country remains import-dependent on potash specifically — see Farmonaut’s coverage of whether the U.S. produces its own fertilizer.

Calculator: Your Per-Acre Potash Cost

Use the component prices above to estimate your own per-acre potash cost, based on your application rate and the price you’re quoted — no hard-coded assumptions about your farm.

Assumptions: converts your target K₂O rate into product tons using the selected grade’s analysis, then multiplies by your quoted price per ton. Defaults reflect the $500/ton Corn Belt retail MOP price and a 60 lb K₂O/acre rate as of August 2026, both of which you should replace with your own current quote and agronomist-recommended rate. Excludes application/spreading cost, freight, and any blending charges for a mixed product like 9-23-30.

Managing Input Costs Without Cutting Yield

Given that potash has no agronomic substitute, the lever farmers actually control is precision — applying exactly what soil test data says is needed, not a blanket rate across a field with variable potassium levels. A few concrete approaches:

• Grid or zone soil sampling: Fields with variable soil types often have potassium levels that differ by 50-100+ ppm across a single field. A flat-rate application overspends on already-adequate zones and underspends on deficient ones.
• Variable-rate application: Once you have zone-level soil data, variable-rate spreading applies potash only where the soil test shows a need, which can reduce total product purchased compared to a uniform rate across the whole field.
• Satellite-based monitoring for in-season correction: Farmonaut’s satellite crop health monitoring can help flag in-season potassium deficiency symptoms (visible as leaf-margin scorch in affected zones) before they show up as yield loss, allowing a targeted rather than blanket response the following season. Learn more about Farmonaut’s advanced agricultural solutions.
• Buying timing: Because retail prices moved from $487/ton in March 2026 to $500/ton in August 2026, locking in a price ahead of a rising trend (where cash flow allows) has a demonstrable cost advantage over waiting, though no one can guarantee the trend continues rather than reversing.

Soil Testing as the Starting Point

Before any rate decision, a current soil test is the only way to know whether a field needs potash at all. Land-grant extension labs (each state’s cooperative extension soil testing lab) typically report potassium as parts per million (ppm) or a categorical rating (low/medium/high) against a state-specific calibration. Because those calibrations and recommended target ranges are state-specific, check your own state extension service’s current fertility guide rather than applying a Corn Belt or national rule of thumb to a different soil type or crop rotation.

Environmental Tradeoffs of Over-Application

Potash itself is less prone to runoff-driven water quality issues than nitrogen or phosphorus, but over-application still wastes money without a yield benefit once soil test levels are already in the “high” category for a given crop and soil type. For broader context on how excess nutrient and mineral inputs affect land and water systems, see Farmonaut’s coverage of environmental consequences of resource extraction, which covers the extraction side of the mineral supply chain that potash itself comes from (potash is mined, predominantly via solution mining and conventional underground mining in Saskatchewan).

Policy support for managing these costs also exists at the federal level — see Farmonaut’s summary of U.S. agricultural subsidies and farmer aid programs for what’s currently available to offset input cost volatility.

The Current Event Driving This: How to Track It Yourself

The single current event underlying every figure in this article is the 25% U.S. tariff on Canadian potash imports, in effect since March 4, 2025, layered onto an already-concentrated supply chain (80% Canadian import share). That is the “why” behind the price movement documented above. It is an active policy, not a closed event, which means the numbers here have a shelf life. To keep your own read current:

1. Check the tariff rate and scope against current USTR/Federal Register notices — rates and product coverage can change by executive action without the lag that price-reporting has.
2. Check current potash pricing at FertilizerPrice.com’s potash tracker or in farmdoc daily’s fertilizer and fuel price roundup, both of which draw on USDA AMS data and update on a rolling schedule.
3. Check your own delivered price with your retailer — the national and regional averages above are directional, not a substitute for a quote against your zip code and volume.

That three-step check — tariff status, national/regional average, local quote — is the durable part of this article: it works whether potash is at $500/ton or $650/ton when you’re reading this.

FAQ

Q: What is 9-23-30 fertilizer used for?
A: It’s a blended starter/pre-plant fertilizer supplying 9% nitrogen, 23% phosphate, and 30% potash — typically chosen for fields with a soil-test-confirmed potassium and phosphorus deficit but adequate existing nitrogen. Confirm the exact blend cost with your retailer, since it isn’t tracked as a standalone USDA series.

Q: What does potash do in fertilizer?
A: It supplies potassium (K), which regulates water use via stomata, activates more than 60 plant enzymes, strengthens cell walls against disease and lodging, and moves sugars into grain during fill. There’s no agronomic substitute for it.

Q: What is the cost of potash per ton right now?
A: $500/ton at Corn Belt retail as of August 7, 2026 (USDA AMS via farmdoc daily), and $535.20/ton as a national average as of September 1, 2026 (USDA AMS via FertilizerPrice.com). Asking-price benchmarks run higher: $694.00/ton for red potash and $744.17/ton for white potash per the current USDA AMS Illinois Cost of Production Report.

Q: What is the potash tariff?
A: A 25% U.S. tariff on Canadian imports, including potash, effective March 4, 2025. Because Canada supplies about 80% of U.S. potash, the tariff had a direct, hard-to-avoid path into retail pricing — CRU Group forecast a $65/metric ton Midwest price increase as a result.

Q: How do fertilizer costs today compare to 2023?
A: This article’s confirmed figures start in March 2026 ($487/ton potash, $677/ton urea) and August 2026 ($500/ton potash, $915.50/ton anhydrous, $912.22/ton DAP), all via USDA AMS. No 2023 USDA AMS figures were available in the sources used for this review — for a historical comparison back to 2023, check farmdoc daily’s archive directly, which maintains prior years’ reports.

Q: How can farmers manage rising potash and fertilizer costs?
A: Soil-test-driven variable-rate application avoids overspending on zones that don’t need it, satellite crop monitoring can catch in-season deficiency symptoms before they cost yield, and locking in pricing ahead of a rising trend (cash flow permitting) has shown a measurable advantage in the March-to-August 2026 data above.

Earn With Farmonaut

Earn 20% recurring commission with Farmonaut’s affiliate program by sharing your promo code and helping farmers save 10%. Onboard 10 Elite farmers monthly to earn a minimum of $148,000 annually—start now and grow your income!

Learn more about Farmonaut’s Affiliate Program

Farmonaut Subscriptions

For more on how satellite monitoring and AI advisory tools tie into input-cost management, explore Farmonaut’s Farmonaut API and API Developer Docs, or see the mineral supply chain context behind fertilizer’s raw materials in Farmonaut’s Minerals Guide.