Guaranteed Analysis
Nutrient Breakdown
N · Nitrogen0%
N/A — Contains no nitrogen. Combine with a nitrogen source if soil tests show nitrogen deficiency
P · Phosphorus46%
Delivers a concentrated 46% phosphorus (P₂O₅) that promotes vigorous root development, stronger stems, abundant flower and fruit production, faster plant maturity, and improved seed formation
K · Potassium0%
N/A — Contains no potassium. Use alongside 0-0-60 Potash if potassium is also needed
Derived from: Triple Superphosphate (Ca(H₂PO₄)₂) — also provides approximately 15% Calcium (Ca)
Overview
What It Is
Triple Superphosphate (TSP) is produced by treating rock phosphate with phosphoric acid, resulting in a concentrated granular fertilizer with 46% phosphorus pentoxide (P₂O₅). It is called 'triple' because it contains roughly three times the phosphorus of ordinary superphosphate (0-20-0). More than 90% of the phosphorus in TSP is water-soluble, meaning it dissolves quickly in soil moisture and becomes available to plant roots within days of application.
Unlike nitrogen, which is mobile in the soil and can leach away with rain, phosphorus is highly immobile. It binds to soil particles and stays in the top few inches where it is applied. This is why incorporating TSP into the root zone at planting time is critical—surface applications are far less effective because the phosphorus cannot migrate downward to reach the roots.
TSP also contains approximately 15% calcium (Ca), which is a valuable secondary nutrient that strengthens cell walls, improves soil structure in acid soils, and supports proper nutrient uptake. This dual-nutrient benefit makes TSP more valuable than simple phosphorus analysis numbers suggest.
Crop Fit
Best For
TomatoesPeppersFruit TreesFlowering BulbsRosesRoot VegetablesBeansAlfalfa
Tomatoes and peppers are heavy phosphorus feeders, especially during transplanting and early fruit set when root establishment is critical. Fruit trees benefit from phosphorus for root development at planting and annual fruiting. Flowering bulbs like tulips, daffodils, and lilies need phosphorus for strong root systems and abundant blooms. Roses respond to phosphorus with more vigorous flowering and healthier cane growth. Beans, alfalfa, and other leguminous crops have a particular affinity for phosphorus fertilization, as noted by agronomic research. Root vegetables like carrots and beets need strong root development that phosphorus supports.
Application Rates
How Much to Use
| Garden & beds | 2.5 lbs per 100 sq ft at planting, worked into the top 6 inches of soil |
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| Lawn | 3-5 lbs per 1,000 sq ft for phosphorus-deficient lawns; check local phosphorus fertilizer restrictions |
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| Trees & shrubs | 1 cup per inch of trunk diameter, applied around the drip line and watered in |
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| Containers | 1 tablespoon per gallon of soil, mixed thoroughly into potting medium before planting |
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| Frequency | Once per season at planting time. Phosphorus is immobile in soil and does not leach, so annual application at planting is typically sufficient. |
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Step by Step
How to Apply
1Soil Test
Test your soil phosphorus levels before applying. Over-application of phosphorus can cause environmental runoff issues and pollute waterways.
2Calculate Rate
Calculate the amount needed based on your area and crop requirements. Standard garden rate is 2.5 lbs per 100 sq ft.
3Broadcast
Spread evenly over the planting area using a broadcast spreader or by hand for smaller areas.
4Incorporate
Work into the top 6 inches of soil with a rake, tiller, or spade. Phosphorus is immobile in soil, so it must be placed in the root zone to be effective.
5Tree Application
For trees, dig fertilizer into the soil around the drip line where feeder roots are most active.
6Water In
Water thoroughly after application to begin dissolving granules and moving phosphorus into contact with roots.
7Timing
Apply once per season, typically at planting time in spring. Phosphorus is most needed during root establishment and early growth.
Always start with a soil test—phosphorus persists in soil for years, and over-application can cause nutrient pollution in waterways. Some states restrict phosphorus fertilizer use on lawns, so check local regulations before applying to turf. For garden beds, broadcast 2.5 lbs per 100 sq ft and incorporate into the top 6 inches of soil before planting. For row vegetables, apply 1 lb per 50 feet of row, banded 2-3 inches to the side and below the seed. For individual transplants like roses and large shrubs, mix 1/4 cup into the planting hole soil. For fruit trees, apply 1 cup per inch of trunk diameter in a ring at the drip line and work into the top few inches of soil. For bulbs, place a small amount of TSP at the bottom of each planting hole. TSP is not for foliar spraying—it is strictly a soil-applied fertilizer. Because phosphorus binds to soil particles and does not leach, a single application at planting is usually sufficient for the entire growing season.
Handling & Timing
Safety & Season
Safety & Storage
Wear gloves and eye protection when handling. Avoid inhaling dust during application. Store in a cool, dry location away from moisture. Phosphorus runoff poses a threat to water quality—do not apply near waterways, storm drains, or on frozen ground. Check state and local regulations regarding phosphorus fertilizer restrictions before applying to lawns. Keep out of reach of children and pets.
Seasonal Notes
Spring: The primary application window. Apply and incorporate into soil before planting vegetables, flowers, and transplanting trees and shrubs. Ideal for preparing garden beds and planting bulbs. Summer: Top-dress flowering annuals and perennials mid-season if phosphorus deficiency symptoms appear (purplish leaves, poor flowering). Fall: Excellent time to apply for fall-planted bulbs (tulips, daffodils, garlic) and to prepare beds for spring planting. Apply to fruit trees after harvest. Winter: Do not apply to frozen ground. Plan soil testing to determine spring application rates.
In Context
How It Compares
Triple Superphosphate (0-46-0) contains the highest concentration of phosphorus among dry granular fertilizers—46% P₂O₅ compared to ordinary superphosphate at just 20%. Compared to rock phosphate (0-12-0), TSP is far more water-soluble and immediately available to plants, while rock phosphate releases slowly over years and works best in acidic soils. Bone meal (3-15-0) is an organic alternative but delivers much less phosphorus per pound and releases more slowly. TSP is the most cost-effective choice when you need maximum phosphorus impact in a single application.
Answers
Frequently Asked Questions
What is triple superphosphate fertilizer?
Triple superphosphate (TSP) is a highly concentrated phosphorus fertilizer with an NPK ratio of 0-46-0, meaning it contains 46% available phosphate with no nitrogen or potassium. It is one of the most efficient sources of phosphorus available to growers. Phosphorus is essential for root development, flowering, fruiting, and energy transfer within plants. TSP is water-soluble and becomes available to plants relatively quickly compared to rock phosphate. Old Cobblers Farm™ Wicked Growth 0-46-0 Triple Phosphate Fertilizer is a premium-grade option for gardeners, farmers, and landscapers who need targeted phosphorus supplementation.
What is triple phosphate fertilizer used for?
Triple phosphate fertilizer (0-46-0) is used to correct phosphorus deficiencies in soil and to support strong root development, flowering, and fruit production. It is especially beneficial at planting time for transplants, bulbs, and new seedlings that need rapid root establishment. Gardeners use it for vegetables, flowers, fruit trees, and shrubs when soil tests indicate low phosphorus. Farmers apply it to field crops to boost yields and improve crop quality. Because it contains no nitrogen or potassium, TSP allows precise phosphorus correction without affecting other nutrients. Old Cobblers Farm™ Wicked Growth 0-46-0 is ideal for targeted phosphorus applications.
How do I apply triple superphosphate to my garden?
Apply triple superphosphate (0-46-0) based on soil test recommendations to avoid over-application. For garden beds, broadcast 1–2 pounds per 100 square feet and incorporate into the top 4–6 inches of soil before planting. For transplants, mix a small amount into the planting hole to encourage rapid root establishment. For established trees and shrubs, apply around the drip line and water thoroughly. Phosphorus does not move easily through soil, so incorporating it into the root zone is important. Old Cobblers Farm™ Wicked Growth 0-46-0 Fertilizer provides fast-acting phosphorus in an easy-to-apply granular form.
Is triple phosphate good for tomatoes?
Yes, triple phosphate (0-46-0) can be very beneficial for tomatoes, especially during transplanting and early growth stages. Phosphorus promotes strong root development, which helps tomato plants establish quickly and access water and nutrients more efficiently. It also supports blossom formation and fruit set. Apply a small amount mixed into the planting hole at transplant time, or incorporate it into garden beds before planting. Avoid over-application, as excessive phosphorus can inhibit the uptake of other nutrients like iron and zinc. Old Cobblers Farm™ Wicked Growth 0-46-0 gives tomatoes the phosphorus boost they need for healthy roots and abundant fruit.
What is the difference between rock phosphate and triple superphosphate?
Rock phosphate (0-12-0) is a slow-release, natural phosphorus source that breaks down gradually over months to years, making it ideal for long-term soil building in organic programs. Triple superphosphate (0-46-0) is a concentrated, water-soluble form that provides phosphorus much more quickly and at nearly four times the concentration. Rock phosphate works best in acidic soils where it dissolves more readily, while TSP is effective across a wider pH range. For immediate phosphorus needs, TSP is the better choice. Old Cobblers Farm offers both options — Wicked Growth 0-46-0 for fast results and Wicked Organics 0-12-0 Rock Phosphate for gradual soil improvement.
How much 0-46-0 fertilizer should I use per acre?
Application rates for 0-46-0 triple superphosphate depend on soil test results and crop requirements. General guidelines for field crops range from 100–300 pounds per acre, which delivers 46–138 pounds of actual P₂O₅. For home gardens, use 1–2 pounds per 100 square feet. For individual trees, apply 1–2 cups around the drip line depending on tree size. Always base your application on a current soil test to prevent phosphorus buildup, which can contribute to nutrient imbalances and environmental concerns. Old Cobblers Farm™ Wicked Growth 0-46-0 Fertilizer provides concentrated phosphorus so a little goes a long way.
Can I use triple phosphate on flowers and bulbs?
Absolutely. Triple phosphate (0-46-0) is one of the best fertilizers for flowers and bulbs because phosphorus directly supports root development and bloom production. For spring-flowering bulbs, mix it into the planting hole in fall to encourage strong root establishment before winter. For annuals and perennials, incorporate it into bed preparation before planting to fuel flowering throughout the season. It is especially effective for roses, dahlias, tulips, daffodils, and other heavy-blooming plants. Old Cobblers Farm™ Wicked Growth 0-46-0 Triple Phosphate Fertilizer helps deliver bigger, more vibrant blooms.
