Specs are compiled from manufacturer listings and verified buyer reviews and can change over time — please confirm the key details on the product page before buying.
Your grass looks green from a nitrogen-rich feed, but that alone won’t get it through a hot summer or a hard frost. For real staying power, your lawn needs potassium — the “K” in N-P-K. A high potassium lawn fertilizer builds strong roots, helps plants handle drought and cold, and is essential for fruit and flower production. This guide covers the purest potassium sources and balanced blends that actually deliver, cutting through the marketing to give you the facts.
I’m Rikta — the founder and writer behind Lawn Gear Lab. This guide is built by comparing the manufacturers’ published specifications and the patterns across verified customer reviews, so you get each pick’s real strengths and trade-offs instead of marketing spin.
If you need a straight potash supplement (a pure potassium source) for a fruit orchard, a liquid feed for your turf, or a balanced fall fertilizer, you’ll find your match here. This is your shortcut to the best high potassium lawn fertilizer for your soil and your goals.
Our Picks at a Glance
How To Choose The Best High Potassium Lawn Fertilizer
Potassium acts as your lawn and garden’s stress shield. It controls water movement, activates enzymes, and builds strong cell walls. A high-potassium feed helps your grass survive a scorching August and bounce back from a hard frost. Here is what to look for when choosing one.
Understanding the N-P-K Ratio
The three numbers on a fertilizer bag are Nitrogen (N), Phosphorus (P), and Potassium (K). For a high potassium fertilizer, you want the last number (K) to be the highest or close to the highest. A bag labeled 0-0-62 is almost pure potassium, while a 10-0-20 gives you a potassium boost with some nitrogen for green growth. Use a high “K” when a soil test shows a deficiency, before winter, or to push fruit and flower production.
Granular vs. Liquid
Granular options, like the Muriate of Potash (0-0-60), release slowly and feed your soil for weeks. They work well for a single, heavy application. Liquid fertilizers, like the 15-0-15 spray, are absorbed by roots and leaves almost immediately. They are ideal for a quick correction or to supplement your granular program during high stress.
Chloride Content: MOP vs. SOP
Muriate of Potash (MOP) is the most common potassium source and works well for most lawns and non-sensitive crops. Sulfate of Potash (SOP) has low chlorine content, making it safer for sensitive plants like blueberries, potatoes, and tobacco. SOP also dissolves in water, so it is great for fertigation (mixing into irrigation water) or foliar feeding (spraying on leaves).
Quick Comparison
| Model | Best For | N-P-K Analysis | Form | Coverage (sq. ft.) | Amazon |
|---|---|---|---|---|---|
| Cz Garden MOP 0-0-62★ Best Overall | Pure potassium boost | 0-0-62 | Granules | N/A | Amazon |
| Superior 15-0-15Top Performer | Liquid green-up + K | 15-0-15 | Liquid | N/A | Amazon |
| Simple Lawn 0-0-25Best Value | Stress & hardiness | 0-0-25 | Liquid | 3,200 | Amazon |
| Cz Garden SOP 0-0-50 | Organic gardening | 0-0-50 | Powder | N/A | Amazon |
| Pendelton Turf 0-0-26 | Rapid stress relief | 0-0-26 | Liquid | 1,000 | Amazon |
| The Andersons 24-0-14 | Fall lawn prep | 24-0-14 | Granules | 5,000 | Amazon |
| Yard Mastery 7-0-20 | Summer stress relief | 7-0-20 | Granules | 6,000 | Amazon |
| Jonathan Green 10-0-20 | Winter survival | 10-0-20 | Granules | 15,000 | Amazon |
In‑Depth Reviews
1. Muriate of Potash 0-0-62 Fertilizer (Cz Garden Supply)
Our pick — over 4.5★ from 900+ verified ratings; the strongest balance of quality and price.
This straight-potash (pure potassium) source turns poor soil into a fruit-producing powerhouse.
When your soil tests low in potassium, this 0-0-62 formula delivers the highest concentration you can buy. It is not a blended lawn feed — it is a pure supplement to correct a specific shortage. Use it to boost flower and fruit density, not just to make grass greener. The 10 lb bag comes in a heavy-duty, resealable pouch, so you pour what you need and store the rest without spills.
The real-world results win people over. Buyers report gardens that finally produced. One owner said, “My dirt is not so good for fruit trees, finally I had fruit using this fertilizer!” It holds a high rating from nearly a thousand buyers, and it is made in the USA from what the brand describes as high-quality ingredients. It gives you more concentrated potassium than the 0-0-50 SOP pick below, but it is not safe for sensitive crops that chlorine can burn.
The catch: this is a specialist tool. It has no nitrogen or phosphorus, so it cannot be your only fertilizer. Think of it as a correction agent, not an everyday feed. If you need an all-in-one lawn fertilizer or a fast-acting liquid, look at the Superior 15-0-15 instead.
What the harvest shows
- Extremely high 0-0-62 potassium concentration for rapid correction.
- Resealable pouch keeps granules dry and easy to store.
- Made in the USA with premium ingredients.
- Highly effective for heavy feeders like fruit trees and tomatoes.
The specialist catch
- Contains no nitrogen or phosphorus — must be supplemented with other fertilizers.
- Granules are slow-release; not for a quick liquid fix.
Reach for this if: you have a confirmed potassium deficiency, want huge yields from fruit trees, or need to amend poor soil.
Look elsewhere if: you want a single all-in-one lawn fertilizer or need a fast-acting liquid feed.
2. Superior 15-0-15 Liquid Fertilizer (Simple Lawn Solutions)
A balanced liquid that greens your turf while strengthening its roots at the same time.
Unlike the pure potassium specialists, this 15-0-15 formula gives you two benefits at once. It delivers 15% nitrogen for deep green color and growth, plus 15% potassium for toughness. It has zero phosphorus, which matters if your local rules restrict phosphorus runoff or if a soil test shows you already have enough phosphorus. The formula also includes humic acid (a natural compound from leonardite that helps roots absorb nutrients better).
The liquid format works fast. Unlike granules that need rain to activate, you can spray this and see a difference within days. You can use a hose-end sprayer, backpack sprayer, or watering can. Owners mention it works well on all grass types, including Bermuda, St. Augustine, and Zoysia. A family-owned business with a background in commercial turf produces it.
But patience matters. One reviewer noted the nitrogen effect “takes a few months to see full results.” It is not a miracle overnight fix, but a solid liquid program. If you want a pure potassium bomb for fruit trees instead, choose the Cz Garden MOP 0-0-62.
Best for the balanced lawn: If you want one liquid product that keeps grass green while building stress tolerance, this is it. skip it if you need pure potassium for fruit or prefer granular-only programs.
Perfect for: the homeowner who wants one liquid product for both green-up and root health.
Consider the 0-0-26 if: you want an even faster-acting, pure stress relief formula without the nitrogen.
3. Simple Lawn Solutions 0-0-25 High Potassium Lawn Food
This pure potassium liquid helps your lawn survive summer heat and get ready for fall.
This 0-0-25 formula skips nitrogen and phosphorus to deliver a focused potassium dose. It is built for one job: helping your lawn handle temperature stress. Use it when grass fades in summer heat or to harden it off before winter. The included hose-end sprayer mixes the perfect ratio automatically, covering up to 3,200 square feet per bottle with no guesswork.
Customers note solid results on root growth and overall health, and they love the easy application. However, the effects are subtle. Potassium works inside the plant — building cell walls and managing water — so you will not see the dramatic green-up from a nitrogen-heavy feed. One buyer mentioned, “I didn’t see a lot of difference in the yard overall.” This product is for the long game: strengthening roots and internal plant health.
The price per ounce is higher than a bag of granular potash, but the convenience of the ready-to-use sprayer is a big plus for busy homeowners. If you want a dramatic color change or need to correct a severe deficiency with a massive K dose, the Cz Garden 0-0-62 granules are a better choice.
Convenience wins
- Includes a ready-to-use hose-end sprayer for even coverage.
- Covers a large 3,200 sq ft area with one bottle.
- Safe for all grass types including Bermuda and Zoysia.
- Excellent for seasonal stress preparation (heat and cold).
Subtle results
- No visible green-up; improvements are internal (root health).
- Some buyers feel the price per ounce is high for a pure potassium product.
Grab this for: an easy, no-mix liquid potassium application before a heat wave or first frost.
Pass if: you want a dramatic color change or need to correct a severe deficiency with a massive dose of K.
4. Organic Sulfate of Potash 0-0-50 (Cz Garden Supply)
This OMRI-listed powder (certified for organic use) feeds your garden without the chlorine risk.
This is the premium choice for organic gardeners. It is Sulfate of Potash (SOP), OMRI-listed, meaning it follows USDA National Organic Program rules. With a 0-0-50 analysis, it delivers high potassium in a water-soluble powder that dissolves instantly. The key difference: it has less than 0.5% chlorine, making it safe for sensitive crops like blueberries, peppers, and potatoes that standard Muriate of Potash (MOP) can burn.
Buyers consistently praise its quality, noting that it “enhances crop color, texture, and taste.” The fine powder works well for hydroponics (growing in water), drip irrigation, and foliar sprays (spraying on leaves). One gardener used it after a soil test showed very low potassium. Despite a five-week drought, their carrots still germinated well and thrived. The product is also pH neutral, so it will not mess with your soil’s acidity.
The trade-off is cost. SOP is more refined than MOP, so the 3 lb bag costs more per pound than the 10 lb bag of 0-0-62 MOP. But it is safer for delicate plants and dissolves fast. Unlike the 0-0-25 liquid that comes with a sprayer, you need to mix this powder with water yourself.
Best for the organic purist: If you grow vegetables or sensitive fruits and want the gold standard potassium source with zero chlorine risk, this is it. Choose the Muriate of Potash if budget and raw K power are your only concern.
Reach for this if: you are an organic farmer, grow chlorine-sensitive crops, or want a fast-acting soluble powder for fertigation.
Look elsewhere if: you need a massive bulk bag for a large lawn or prefer the no-mix convenience of granular MOP.
5. Pendelton Turf Supply 0-0-26 Foliar Phosphite Liquid Fertilizer
This biostimulant (a substance that boosts natural plant processes) builds your plants’ defense systems from the inside.
This product works differently than standard potassium fertilizers. It delivers 26% soluble potash (water-soluble potassium), but it uses a “phosphite” form instead of standard phosphate. Phosphite acts as a biostimulant, helping trigger a plant’s natural defenses against stress and disease. It is not a cure — it is a prevention tool. It comes from potassium hydroxide and phosphorus acid.
The liquid absorbs fast, making it great for a quick boost. Buyers in hot climates, like Hawaii, report it makes a massive difference for citrus trees struggling to set and hold fruit when granules are too slow. Another user said it helped live oaks recover from post-hurricane fungal spotting. The squeeze bottle design doubles as a measuring cup, so you pour exact doses without extra tools.
But packaging is a known issue. Some units arrive leaky or under the fill line, which frustrates buyers. As a specialty biostimulant, it is not a general-purpose fertilizer. It delivers potash, but its main value is the phosphite action for plant immunity. If you just want straight potassium without the biostimulant, the Simple Lawn 0-0-25 is a better fit.
Resilience booster
- Phosphite formulation builds plant defense against stress and disease.
- Fast liquid uptake for rapid results on trees and turf.
- Easy-to-use squeeze bottle measures doses directly.
- Excellent for improving drought tolerance in ornamental plants.
Packaging risk
- Some units arrive with leaky packaging or below fill line.
- More of a specialty biostimulant than a general potassium fertilizer.
Best for: the turf manager or gardener fighting summer stress, fungus, or needing a fast-acting root stimulant.
Pick the 0-0-25 instead if: you just want straight potassium without the phosphite biostimulant action.
6. The Andersons Premium Fall Lawn Food 24-0-14 Fertilizer
This timed-release fall feed greens up fast and stores energy for winter survival.
This is the fourth step in The Andersons’ lawn program, and it does two jobs. The 24% nitrogen gives your lawn one last deep green push before dormancy, while the 14% potassium hardens it off for winter. The nitrogen comes in quick-, intermediate-, and slow-release forms. You get a fast green-up in days, but feeding continues for weeks without a growth surge that would leave grass vulnerable to frost. It covers up to 5,000 square feet per 18 lb bag.
Buyers consistently call it the best fertilizer they have used. One buyer in DFW said that after a few weeks and some rain, it outperformed a professional landscape company’s service. The added iron gives an extra deep-green effect without the weak growth from too much fast nitrogen. Compared to the Jonathan Green 10-0-20 below, this one delivers a faster green-up but covers less area per bag.
The main limitation is seasonal timing. It is designed for fall prep, not year-round use. Applying it in spring would push too much green growth at the wrong time. The 5,000 sq ft coverage is smaller than some competitor bags, so large lawn owners may need multiple bags.
The fall specialist: If you want one bag that greens up your lawn for the last mow of the year while building winter hardiness, this is it. pass on it if you need a spring or summer feed.
Reach for this when: the leaves start falling and you want one last green show before winter dormancy.
Look at the 7-0-20 instead if: you are fighting summer heat stress and need a mid-season potassium boost.
7. Yard Mastery 7-0-20 Summer Lawn and Turf Stress Granular Fertilizer
This cool-weather granular offers relief from summer heat stress.
When your lawn is stressed, you need a specific ratio. This 7-0-20 blend includes 3% iron and Bio-Nite technology. The 20% potassium strengthens cell walls and improves water retention during drought. The 3% iron provides a “hearty pop of color,” making grass look healthier even in the heat. It is safe for all lawn types and can be applied year-round, but its true strength is in late spring and summer. It covers 6,000 square feet per 18 lb bag, giving you more coverage than The Andersons 24-0-14.
This product has a strong following. Owners praise its effectiveness and quality. One owner of centipede and zoysia in North Carolina said it revived his 15-year-old centipede lawn from summer stress, calling it “worth it.” Experienced users advise applying only when temperatures are under 80°F, and watering it in heavily for three to four days to avoid burn.
The downside is the application restrictions. It is not a “low-maintenance” granular. It needs careful timing to avoid the hottest weather and consistent watering to activate. If you want a flexible liquid sprayer or a product you can use in July without worry, this may be too high-maintenance.
Stress buster
- High 20% potassium content for superior heat and drought tolerance.
- Includes 3% iron for a visible color boost.
- Large coverage (6,000 sq ft per bag) for big lawns.
- Safe for centipede, zoysia, Bermuda, and fescue.
Needs careful timing
- Must be applied only when temperatures are under 80°F.
- Requires several days of heavy watering to avoid burn.
Reach for this if: you have a large lawn fading in the summer heat and want a targeted granular recovery plan.
Pass if: you need a flexible all-season feed or cannot commit to the strict watering schedule.
8. Jonathan Green Winter Survival Fall Lawn Food 10-0-20
This massive 45 lb bag feeds your lawn through winter so it pops up stronger in spring.
This is the heavy hitter for large properties. With a 10-0-20 analysis, it delivers 20% potassium for deep rooting and nutrient storage, plus 10% slow-release nitrogen. The “Winter Survival” name is literal: it hardens off the turf so it endures winter and emerges greener and thicker in early spring. It is designed as a repair product for summer damage, making it the ideal last application of the year. The 45 lb bag covers up to 15,000 square feet, giving you the largest coverage of any pick here — 15,000 sq ft versus the Andersons 5,000 sq ft.
Quality and appearance are the most-praised aspects. One owner who switched from a big-box brand called it “wonderful,” saying, “My lawn never has looked this beautiful.” Another used it on a pasture and got a “super green” result. The slow-release nitrogen fuels growth without a fast, weak spurt that frost would kill. The granules are large, so a good-quality spreader is recommended for even distribution.
The main consideration is seasonal timing. This is strictly a fall product — using it in spring would push the wrong growth signals. Some buyers also noted that newer grass on a lawn did not survive winter despite the application, which is a reminder that no fertilizer fixes everything.
Best for the large lawn owner: If you want a single, big bag that preps your turf for winter and delivers a head start in spring, this is the play. Choose The Andersons 24-0-14 if you have a smaller lawn and want the fastest fall green-up.
Grab this for: massive coverage (15,000 sq ft) and a professional-grade winter prep feeding.
it’s not for you if: you need a summer or spring feed or want a liquid formula for quick spot-treating.
Understanding the Specs
N-P-K Ratio
This is the fertilizer’s chemical ID. The first number (N) promotes green leaf growth. The second (P) is for root development and blooms. The third (K) is for overall plant health, stress tolerance, and fruit production. For a high potassium product, always check that the third number is high — ideally the highest in the trio.
Potassium Source (MOP vs. SOP)
The two main sources are Muriate of Potash (MOP, high in chlorine) and Sulfate of Potash (SOP, low in chlorine). MOP is cheaper and works for most lawns. SOP is safer for sensitive crops, is water-soluble, and is preferred for organic gardening.
FAQ
What does high potassium fertilizer do for my lawn?
When should I apply a high potassium fertilizer?
Can I use a 0-0-60 fertilizer on my lawn?
What is the difference between Sulfate of Potash and Muriate of Potash?
Is liquid or granular potassium fertilizer better?
Can I use a fall high-potassium fertilizer in the spring?
Will high potassium fertilizer burn my lawn?
How do I know if my soil needs potassium?
Final Thoughts: The Verdict
The best high potassium lawn fertilizer for most people is the Cz Garden Supply Muriate of Potash 0-0-62. It packs the most concentrated potassium punch at a fair price, backed by a high rating from nearly a thousand buyers. If you want a balanced liquid feed for your whole lawn that builds health while greening up, go with the Simple Lawn Solutions Superior 15-0-15. And for the organic gardener who needs a fast-acting, low-chlorine potassium source for sensitive vegetables, the Cz Garden Supply Sulfate of Potash 0-0-50 is the one to reach for.
How We Picked
We do not accept paid placement. Every pick is matched to a real buyer and a real use-case; we do not hands-on test units.
Sources & Methodology
Specifications: manufacturer listings and product documentation. Review insights: verified customer reviews, as of July 2026. Pricing: not shown on this page (it changes often); check the current price via the retailer link.
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