Triple Super Phosphate (0-46-0) is a dry granular fertilizer with 46% available phosphorus and no nitrogen or potassium—the most concentrated dry phosphorus source available.
A soil test that shows low phosphorus calls for 0-46-0 fertilizer—and understanding what is 0-46-0 fertilizer and how it works keeps you from wasting money or harming your soil. The three numbers mean 0% nitrogen, 46% available phosphate (P₂O₅), and 0% potassium. Knowing when it’s actually needed and how to apply it correctly makes the difference between a thriving lawn and a costly mistake.
What Exactly Is 0-46-0 Fertilizer?
0-46-0 fertilizer is Triple Super Phosphate (TSP), chemically known as monocalcium phosphate (Ca(H₂PO₄)₂·H₂O). Each granule contains about 15% calcium alongside the phosphorus, which provides a minor secondary-nutrient benefit in acidic soils. It’s the highest-concentration dry phosphorus source available without nitrogen, making it the right choice when your soil test shows phosphorus is low but nitrogen and potassium are already sufficient.
TSP is granular and meant for dry broadcast or banded application. It won’t dissolve fully in water for spraying as a solid—you’d need a different product for foliar feeding. Standard bags run 50 pounds, and prices typically land between $35 and $50 per bag depending on the brand. Triple S Super Phosphate from American Plant Food is one common option on the market. Because it delivers no nitrogen or potassium, you’ll need separate products for those nutrients if your soil requires them.
When Should You Use 0-46-0?
Only apply 0-46-0 after a soil test confirms a phosphorus deficiency, as the University of Minnesota Extension strongly advises. Using it without a test can build up phosphorus in the soil, which then runs off into waterways and creates algae problems. This is a targeted correction tool, not a routine addition.
Crops that benefit most include legumes (beans, peas), vegetables (tomatoes, peppers, and fruiting crops), fruits, and lawns establishing new sod or seed. If your soil already has adequate phosphorus, save your money and skip it entirely.
A few common mistakes trip people up. Treating it as a complete fertilizer is another common error—0-46-0 provides no nitrogen or potassium, so those must come from separate products. And because TSP is less soluble than DAP or MAP, it’s not ideal for cold soils where quick release matters. Sulfur supplementation may also be needed since TSP lacks that nutrient.
How To Apply 0-46-0 Fertilizer
Apply 0-46-0 at 3–5 pounds per 1,000 square feet for general lawn correction, going up to 5 pounds for severe confirmed deficiencies. The table below shows recommended rates for common scenarios.
| Use Case | Application Rate | Timing & Notes |
|---|---|---|
| Lawn correction (general) | 3–5 lb per 1,000 sq ft | Early spring or before seeding; water in |
| Lawn (severe deficiency) | Up to 5 lb per 1,000 sq ft | 2–3 weeks before planting |
| Garden beds (general) | 1–2 tsp per sq ft | Incorporate 2–3 weeks before planting |
| Established plants (side-dress) | Same garden rate | During growing season; water in |
| Liquid drench | 1 tsp per gallon water | Every 4–6 weeks |
| Seedlings (drench only) | ¼–½ tsp per plant | Every 4–6 weeks; lower rate to avoid burn |
| Pre-planting incorporation | Work into 3–6 inch depth | 2–3 weeks ahead of planting |
Incorporate the granules into the top 3–6 inches of soil 2–3 weeks before planting, then water thoroughly afterward to move phosphorus into the root zone. For established plants, side-dress during the growing season at the same garden-bed rate, keeping granules away from stems.
If you’re ready to buy, our roundup of the best 0-46-0 fertilizer products compares top brands and prices to help you choose.
FAQs
Can I mix 0-46-0 with other fertilizers?
Yes, you can blend 0-46-0 with nitrogen and potassium sources to create a custom complete fertilizer, but mix thoroughly to prevent uneven application. Avoid combining it with urea in humid conditions, since the mixture can form a sticky cake that clogs spreaders.
Is 0-46-0 the same as super phosphate?
No. Triple Super Phosphate (0-46-0) is about three times more concentrated than ordinary super phosphate (0-20-0). You apply less material per pound of phosphorus, so a bag of TSP goes further and costs less per unit of P.
How long does 0-46-0 last in the soil?
The phosphorus is water-soluble and plant-available quickly, but it can start reverting to less available forms within weeks under poor conditions. Apply it close to planting time for the best uptake, and keep soil pH between 6.0 and 7.0 for maximum availability.
References & Sources
- University of Minnesota Extension. “Understanding Phosphorus Fertilizers.” Comprehensive guide on phosphorus fertilizer types and soil test recommendations.