5-10-30 Fertilizer: N-P-K Ratios, Rates & Costs

Reviewed September 2026 against USDA NASS, USDA AMS, USDA ERS, and California Department of Food & Agriculture (CDFA) fertilization guidelines.

Try it: Run your own numbers →

5-10-30 fertilizer is 5% nitrogen (N), 10% phosphorus as P₂O₅, and 30% potassium as K₂O by weight — a potassium-heavy blend built for potatoes, tomatoes, and orchard crops. 10-10-30 fertilizer raises nitrogen to 10% for a more balanced feed suited to cereals and reclamation seedings. 5-0-20 fertilizer drops phosphorus entirely, for soils that already test high in P. None of these ratios has a published national price or a USDA-tracked adoption rate — this article shows you why, and gives you the numbers that do exist so you can price and rate your own application correctly.

Table of Contents

1. What the Numbers Mean: N-P-K Explained
2. 5-10-30 Fertilizer: Rates, Crops, and What the Research Shows
3. 10-10-30 Fertilizer: The Balanced-Nitrogen Option
4. 5-0-20 Fertilizer: When to Skip Phosphorus
5. Comparison Table: 5-10-30 vs. 10-10-30 vs. 5-0-20
6. Calculator: Estimate Your Potash Cost per Acre
7. Verifying Rates: Soil Tests, Precision Application, and Runoff Limits
8. How Farmonaut Supports Precision Fertilizer Management
9. FAQ
10. Conclusion

What the Numbers Mean: N-P-K Explained

Every fertilizer label — 5-10-30, 10-10-30, 5-0-20, or any other three-number sequence — states the guaranteed analysis as percentage by weight, always in the same order: Nitrogen (N), Phosphorus (expressed as P₂O₅), then Potassium (expressed as K₂O). A 50 lb bag of 5-10-30 contains 2.5 lb of actual nitrogen, 5 lb of P₂O₅, and 15 lb of K₂O; the remaining weight is filler and carrier material. That arithmetic is fixed by the Association of American Plant Food Control Officials (AAPFCO) definition used on every US fertilizer tag, so it does not change year to year — only the recommended rates and prices below do.

• Nitrogen (N): drives vegetative growth and leaf development.
• Phosphorus (P₂O₅): supports root establishment, energy transfer, and flowering.
• Potassium (K₂O): governs disease resistance, drought tolerance, and fruit or tuber formation.
• Try it: Run your own numbers

A blend written as “5-10:30” or “5+10+30” is the identical formula — the separator is a typing artifact, not a different product. Searching “5 10 30” alone almost always means this fertilizer ratio rather than a time or a score, and that is the reading used throughout this article.

5-10-30 Fertilizer: Rates, Crops, and What the Research Shows

5-10-30’s defining feature is its 30% K₂O share, the highest potassium concentration of the three ratios covered here. That places it in the same functional category as the potassium programs the University of Idaho and CDFA document for potato production, even though neither agency publishes a recommendation for the 5-10-30 blend by name — extension guidance is written around nutrient rates per acre, not around specific bag ratios, and a grower buying any K₂O-heavy blend applies it to hit the same per-acre target.

For context on how much potassium a demanding crop actually removes: University of Idaho and USDA Agricultural Research Service data on russet potatoes show a 400–500 cwt/acre yield draws down 280–320 lbs/acre of potassium over the season (University of Idaho / USDA ARS). CDFA’s current potato fertilization guideline sets a lower application figure of 160–280 lbs/acre K₂O for a 400 cwt/acre crop, reflecting what soil already supplies versus what must be added, and estimates the crop itself removes 40–70 lbs/acre K₂O per 100 cwt harvested (California Department of Food & Agriculture). CDFA’s target exchangeable soil potassium level for potato ground is 150 ppm on an ammonium-acetate test — pull a soil test against that number before deciding whether a 30% K₂O blend is even necessary on your field.

On the yield side, peer-reviewed research compiled by the University of Florida’s EDIS service found potassium application increased total potato tuber yield by 10% and increased US No. 1 grade yield specifically by 12% (University of Florida / EDIS). Those figures describe potassium’s contribution generally, not the 5-10-30 blend by name — no open-access US field trial isolates that exact ratio against a control, which is a genuine gap in the public record rather than an oversight on our part. If a supplier’s literature claims a specific yield lift for 5-10-30 itself, ask for the trial data behind it before relying on the number.

• Target crops: crops needing strong root systems and fruit or tuber development
  • Potatoes
  • Tomatoes
  • Orchards (apples, citrus, olives)
  • Root vegetables
  • Floriculture and select medicinal crops

For availability and current bag pricing of the 5-10-30 ratio specifically, check with a local farm co-op or retailer — USDA does not publish retail prices broken out by NPK ratio (see the cost section below for what USDA does track: the underlying commodity inputs).

10-10-30 Fertilizer: The Balanced-Nitrogen Option

10-10-30 doubles the nitrogen share of 5-10-30 (10% vs. 5%) while holding phosphorus and potassium constant. That makes it the better fit where a soil test shows a real nitrogen shortfall alongside high potassium demand, rather than a K-only deficiency. USDA NASS reported average nitrogen application on US corn at 151.8 lbs/acre and on US wheat at 77.15 lbs/acre for the 2024 crop year (USDA NASS) — corn alone accounts for 78% of total US nitrogen fertilizer consumption, which is why nitrogen-carrying blends like 10-10-30 are marketed heavily into corn and cereal rotations.

• Blend: 10% N | 10% P₂O₅ | 30% K₂O
• Typical use:
  • Cereals: wheat, maize, barley
  • Grain quality and test-weight improvement
  • Cover crops and post-mining reclamation seedings

On phosphorus and potassium banding specifically — the two nutrients 10-10-30 shares with 5-10-30 — Iowa State Extension research spanning more than 100 field trials since 1994 found deep-banded P+K application raised corn yield by 4–8 bu/acre, with the size of the response depending on tillage system (Ohio State University Extension, Agronomic Crops Network). That is a placement effect, not a ratio effect — it applies to any P+K blend banded near the row, 10-10-30 included, and it is the closest published figure to a direct yield answer for this ratio’s core nutrients.

5-0-20 Fertilizer: When to Skip Phosphorus

5-0-20 carries no phosphorus at all, which matters in two situations: soil tests already show excess P (common on fields with a long manure-application history), or local runoff rules restrict adding more phosphorus near waterways. Dropping the P₂O₅ line while keeping a substantial 20% K₂O share lets a grower keep feeding potassium without pushing soil phosphorus higher.

• Formula: 5% Nitrogen, 0% Phosphorus, 20% Potassium
• Use when:
  • Soil tests show adequate or excess phosphorus
  • The crop has high potassium demand but no added-P need
  • Land sits near surface water with phosphorus-runoff restrictions

On documented field use: published sources describe 5-0-20 mainly in lawn and turf products and specialty liquid formulations rather than row-crop programs — row-crop and sugarcane adoption of this exact ratio is not verified in USDA data, which is a genuine gap rather than a number we are willing to guess at. If you are considering 5-0-20 for a field crop, run it past your state extension agronomist with your own soil test in hand rather than a generic recommendation, since the public research base for this specific ratio in row crops is thin.

• Crop suitability: sugarcane, onions, garlic, and other high-K₂O-demand crops on phosphorus-sufficient ground — verify locally before scaling up.

Comparison Table: 5-10-30 vs. 10-10-30 vs. 5-0-20

No agency publishes a side-by-side yield table for these three exact ratios, so the table below separates what is verified guaranteed-analysis math from what is sourced agronomic evidence for the nutrients each blend carries — use it to decide which ratio fits your soil test, not as a promise of a specific yield number.

Calculator: Estimate Your Potash Cost per Acre

Retail prices for a bagged 5-10-30, 10-10-30, or 5-0-20 blend aren’t published by USDA or any manufacturer’s public filing — the figures below come from USDA AMS commodity spot prices for the raw inputs blenders buy, so use this tool to estimate a cost range for your own acreage and rate, then compare it against your local retailer’s quote.

Assumptions: this estimates only the nitrogen and phosphorus input cost share of the blend, using USDA AMS Q1-Q2 2026 spot ranges of $330-$415/short ton for urea and $560-$660/short ton for DAP as your starting defaults — edit them to today’s quote from USDA AMS Market News. It excludes the potassium (MOP) input cost, blending, bagging, freight, and application labor, none of which are published at the ratio level, so treat the output as a partial floor, not a full delivered price.

For scale, USDA’s 2026 forecast puts total fertilizer cost at $165-$166/acre for corn production and $57/acre for soybeans (USDA Economic Research Service) — a useful benchmark to sanity-check whatever the calculator above returns for your own rate and acreage.

Verifying Rates: Soil Tests, Precision Application, and Runoff Limits

The figures in this article — USDA’s per-crop nitrogen rates, CDFA’s potassium removal ranges, the AMS commodity spot prices — are all refiled on a schedule, which means the numbers you see today will move. Here is exactly where and how often:

1. Where the Numbers Get Updated

• USDA NASS Quick Stats (data.nass.usda.gov): query “Fertilizer Applied” by commodity, state, and year — refreshed annually each May with the prior year’s application rates.
• USDA NASS Price Received / Cost of Production: updated quarterly for major field crops via the same Quick Stats interface.
• USDA AMS fertilizer spot prices (ams.usda.gov, Market News section, “Fertilizer”): updated daily.

Bookmark those three sources rather than this article’s numbers if you’re pricing an application more than a season out.

2. Soil Testing Before Ratio Selection

• CDFA’s guideline uses an ammonium-acetate exchangeable-potassium test with a 150 ppm target for potato ground — request the same test method from your local lab so your result is comparable to the published thresholds.
• Farmonaut delivers: real-time monitoring of soil condition and vegetative health via satellite, to flag where a soil test is worth pulling (see large-scale farm management features).

3. Placement Technique Changes the Yield Response

• The 4–8 bu/acre corn response to P+K documented by Ohio State Extension came specifically from deep-banded placement near the row, not broadcast application — the same pounds of nutrient, applied differently, produced different results across those 100+ trials.

4. Traceability for Input Records

• Farmonaut’s Blockchain Traceability Tools log fertilizer inputs against field records for certification and buyer audits.

5. Runoff and Phosphorus Limits

• Where local rules cap phosphorus near surface water, a zero-P blend like 5-0-20 avoids adding to the load — precision application tools reduce runoff further by matching rate to verified soil-test need rather than a flat per-acre default.
• Farmonaut’s API (explore API offerings) can feed field-level data into resource-use audits for compliance reporting.

6. Carbon and Ecosystem Reporting

• Recording which N-P-K ratio was applied, and at what rate, feeds directly into carbon-footprint calculations via Farmonaut’s Carbon Footprinting Module, relevant for growers in voluntary or regulatory carbon programs.

7. Fleet and Logistics for Timely Application

• Farmonaut Fleet Management schedules input delivery so blends reach the field inside the application window the soil test and crop stage call for.

For Agroforestry and Plantation Projects

• Farmonaut’s Crop Plantation & Forest Advisory service supports species choice, fertilizer planning, and growth tracking for reclamation and long-rotation plantings.

How Farmonaut Supports Precision Fertilizer Management

Choosing between 5-10-30, 10-10-30, and 5-0-20 comes down to a soil test and a crop plan — the platform’s role is making sure both are current before you buy:

• Real-time monitoring: multispectral satellite analytics for crop health, soil nutritional status, and irrigation needs.
• Decision tools: Farmonaut’s Jeevn AI system delivers tailored fertilizer-timing recommendations based on field-specific data.
• Environmental compliance: integrated carbon and resource tracking to support sustainability verification and financing access.
• Blockchain-enabled traceability: securely documents each fertilizer batch applied, for supply-chain audits.
• Fleet and resource management: coordinates logistics for precision application timing across large land holdings.

FAQ

Conclusion

5-10-30, 10-10-30, and 5-0-20 are three points on the same spectrum: how much nitrogen and phosphorus you carry alongside a heavy potassium dose. The right choice is set by your soil test, not by a general claim about yield — CDFA’s 150 ppm exchangeable-potassium target and the 40-70 lbs/acre K₂O per 100 cwt removal rate give you a concrete benchmark to test against for potassium-demanding crops, and USDA NASS’s annual Quick Stats release each May keeps the nitrogen-rate comparisons current for corn and wheat.

Where the public record has a real gap — retail pricing by exact ratio, and field trials on 5-0-20 in row crops — this article has said so plainly rather than filling it with an invented number. Use the calculator above with your local input prices, verify your rate against a current soil test, and check USDA AMS and NASS directly when you need a number fresher than the one printed here.