Nitroform Fertilizer 39-0-0
- Regular Price
- $ 21.99
- Sale Price
- $ 21.99
- Regular Price
- $ 21.99
Sold Out
- Unit Price
- per
Greenway Biotech · Made in California since 1989
Nitroform 39-0-0 Slow Release Nitrogen.
One feeding. A whole season.
A CDFA-registered urea-formaldehyde nitrogen source delivering 39% N, with roughly 73% as water-insoluble nitrogen (WIN) that soil microbes meter out over 8–12 weeks. Low burn risk, low leaching, and ideal as the slow-release component of a turf, tree, container, or landscape program.
Find your size → Calculate how much I need39%
Total nitrogen by weight — one of the most concentrated slow-release nitrogen sources available
73%
Water-insoluble nitrogen (WIN) — metered by soil microbes, not by rainfall
8–12wks
Feeding duration per application in warm, moist soils above 55°F
35+yrs
Family-owned California manufacturer of specialty fertilizers since 1989
01 / Choose your size
Right-sized for
the job.
Coverage figures assume a typical maintenance turf rate of about 1.5 lb actual N per 1,000 sq ft (roughly 4 lbs of Nitroform). Trees use far less per unit of product, and field crops require much more — see the Application section for full rate tables.
| Bag Size | Lawn Coverage | Trees (drip-line app.) | Best For |
|---|---|---|---|
| 1 lb | ~250 sq ft | 1–2 small trees | Trial size, containers |
| 5 lb | ~1,250 sq ft | 5–10 small/medium trees | Small-yard maintenance |
| 10 lb | ~2,500 sq ft | 10–20 small/medium trees | Most popular |
| 25 lb | ~6,250 sq ft | 25–50 trees / orchard row | Larger lawns & landscapes |
| 50 lb | ~12,500 sq ft | 50–100 trees / small acreage | Best value |
02 / Ideal applications
One bag.
Six different jobs.
Nitroform performs best where you want extended feeding, low burn risk, and reduced leaching — especially on turf, trees, and containers. It is not a quick-correction fertilizer; pair with a quick-release N source where rapid response is needed.
Cool- & Warm-Season Lawns
The slow-release component of standard turf programs. Penn State and Purdue recommend slow-release N for 25–50% of the seasonal fertility budget — Nitroform fits that role.
Established Trees & Shrubs
Peer-reviewed research (Watson 2010; Khatamian et al. 1984) supports Nitroform for established and newly planted trees at ANSI A300 / ISA BMP rates.
Container Nursery Stock
Univ. of Florida IFAS BMP work supports low-rate Nitroform in container media for reduced N leaching. Excellent for nursery and ornamental container production.
Landscape & Ornamental Beds
Sustained feeding for perennials and ornamentals without surge growth. Plant safety is excellent at label rates — useful around sensitive species.
Vegetables & Field Crops
Use with caution — Penn State documents lower first-year N recovery vs. quick-release sources. Best paired with a soluble N source for annual crops, not used alone.
Custom Slow-Release Blends
Dust-free, uniform mini-granules blend cleanly with phosphorus and potassium sources, making Nitroform a workhorse for custom fertilizer programs.
03 / Why Nitroform
Slow-release done right.
Without compromise.
Most slow-release nitrogen sources trade concentration for safety, or burn risk for fast response. Nitroform's urea-formaldehyde chemistry brings high N concentration, microbial-paced release, and very low burn risk into one product — the same chemistry trusted on professional golf courses, in tree care, and in container nurseries since the 1960s.
39%
One of the most concentrated slow-release N sources available.
Higher N concentration than feather meal (12%), blood meal (13%), or ammonium sulfate (21%). At 39% N, you move less product per pound of actual nitrogen delivered — useful for large-area applications where freight and labor are real costs. For deeper background, see Function of Nitrogen in Plants.
73%
Water-insoluble nitrogen does the work.
Of the 39% total N, roughly 73% is water-insoluble nitrogen (WIN) — the fraction that resists rainfall and irrigation, and is released only as soil microbes break down the urea-formaldehyde polymer. This is why Penn State turfgrass programs use Nitroform as the slow-release portion of cool-season fertility budgets.
Lowburn
Very low burn risk at label rates.
Because the WIN fraction doesn't dissolve and spike the soil solution, salt-driven root injury is uncommon at recommended rates. Khatamian, Pair & Carrow (1984) confirmed this in field-grown bare-root honeylocust transplants — Nitroform applied at planting increased trunk diameter without injury at 0.5 lb per young tree.
8–12wks
Microbial pace, not weather pace.
Release rate is driven by soil microbial activity, which tracks soil temperature and moisture. In warm, moist soils above 55°F you can expect 8–10 weeks of feeding per application; in cool or dry conditions, expect closer to 10–12 weeks with a slower-curve front end. Soil Microbes & Plant Health covers the underlying biology.
CDFA
State-registered, lab-tested, made in California.
Manufactured and packaged in Madera, CA under CDFA fertilizer registration. Independently lab tested for heavy metals, with results consistently well below required limits. Same family ownership since 1989.
$/N
Often the lowest-cost slow-release N on a per-pound-of-actual-N basis.
At 39% N, each pound of Nitroform delivers about 0.39 lb of actual nitrogen. For programs that already use slow-release N as a budget item — turf, tree care, container nursery — Nitroform is often the lowest-cost option on a $/lb-N basis among true slow-release sources. Run the math against your current program with the calculator below.
04 / The science
Why urea-formaldehyde
changes the release curve.
73% WIN
Urea-Formaldehyde (Methylene Urea) — (NH₂)₂CO · HCHO polymer
Nitroform is manufactured by reacting urea with formaldehyde in roughly a 1.3:1 ratio under controlled conditions. The reaction builds methylene urea polymer chains of varying length — short chains that release nitrogen relatively quickly, and longer chains that resist breakdown for months. The result is a single granular product with a built-in release-curve spread.
Per university extension classifications, ureaform fertilizers should contain at least 35% nitrogen with at least 60% of that nitrogen as water-insoluble nitrogen (WIN). Nitroform meets this threshold at 39% total N and roughly 73% WIN — placing it firmly in the “slow-release” category by the Association of American Plant Food Control Officials definition.
Release happens through microbial enzymatic action, not chemical dissolution. Soil bacteria and fungi gradually cleave the methylene-urea bonds, freeing urea that is then hydrolyzed to ammonium and nitrified to nitrate. Because the release depends on microbial metabolism, soil temperature is the dominant variable: very little release below 50°F, optimal release in warm moist soils above 55°F.
The practical implication is that Nitroform performs best when matched to the right job. It is excellent for sustained feeding of established turf, trees, shrubs, ornamentals, and container nursery stock. It is less well suited as a stand-alone N source for short-cycle annual vegetables, where Penn State documents lower first-year nitrogen recovery; pair Nitroform with a quick-release N source in those situations, or use a quick-release source instead.
For a broader survey of nitrogen sources and where each one fits, see our guide: Best Nitrogen Fertilizer for Your Garden, Lawn & Hydroponics.
05 / Application rates
Pick your use.
Get your rate.
All rates below are drawn from university extension publications, peer-reviewed arboriculture research, ANSI A300 / ISA Best Management Practices, and the registered Nitroform product label. Adjust to local soil-test results and crop demand.
Lawn & Turf Maintenance
Quick answer: About 2.6–5.1 lb of Nitroform per 1,000 sq ft per application (delivering 1.0–2.0 lb actual N), every 8–12 weeks during the growing season. Use the higher end of the range when Nitroform is the sole N source — first-year recovery is lower than quick-release sources.
| Use Case | Actual N target | Nitroform per 1,000 sq ft | Source | Notes |
|---|---|---|---|---|
| Maintenance, cool-season turf | 1.0–2.0 lb N | 2.6–5.1 lb | Penn State Ext. | Use the higher end of the range when Nitroform is the only N source applied |
| Maintenance, warm-season turf | 1.0–2.0 lb N | 2.6–5.1 lb | Penn State Ext. | Apply in late spring through mid-summer when soil temps are above 55°F |
| Greens, tees, sports turf (SGN 75–150 product) | 0.5–1.0 lb N | 1.3–2.6 lb | Penn State Ext. | Lower per-application rate; integrate with frequent feeds & foliar programs |
| Annual total (split, 2–3 apps) | 3–5 lb N / yr | 7.7–12.8 lb / yr | Purdue Turfgrass Science | Adjust to species, mowing height, climate, and soil test |
First-year recovery note: Penn State Extension documents lower nitrogen recovery from ureaform sources in the first one to two years of use. Plan to use the higher end of the rate range, or pair Nitroform with a quick-release nitrogen source (typically 25–50% of the total N as soluble urea or ammonium sulfate) during establishment.
Sources: Penn State Extension Center for Turfgrass Science; Purdue University Turfgrass Science (fall fertilization guidelines); Greenway Biotech / Nitroform manufacturer label.
Trees & Shrubs
Quick answer: Established landscape trees: roughly 5–15 lb of Nitroform per 1,000 sq ft of fertilized root-zone area per year (ANSI A300 / ISA BMP). Newly planted bare-root trees: about 0.5 lb (227 g) per young tree, incorporated into backfill (Khatamian, Pair & Carrow 1984).
| Application | Rate | Source | Notes |
|---|---|---|---|
| Established trees, broadcast root-zone (annual) | 5.1–15.1 lb / 1,000 sq ft / yr | ANSI A300 / ISA BMP; Watson 2010 | Range equals 0.96–2.88 kg N / 100 m²/yr; ~6.6 lb / 1,000 sq ft is the midpoint standard arborist rate |
| Established tree, inner half of root zone | ~1.0 lb / tree (16-ft canopy diameter) | Watson 2010, Arboriculture & Urban Forestry | Concentrating Nitroform near the trunk (inner half) outperformed full-canopy broadcast in green ash |
| Bare-root tree at planting (~2–2.5 cm caliper) | ~0.5 lb / tree (227 g) | Khatamian, Pair & Carrow 1984, J. Arboriculture | Honeylocust field study (KSU). Doubling to 1.0 lb did not increase growth |
| Maintenance, by trunk caliper | ~0.5 lb per inch DBH | Greenway Biotech / Nitroform label; consistent w/ Khatamian 1984 | Broadcast around the drip line, not against the trunk; water in thoroughly |
| Container or B&B preplant | ~1.0 lb per gallon container or wrapped ball | Greenway Biotech / Nitroform label | Mix into backfill; reduce in extremely warm, moist climates where release accelerates |
Placement note: Watson (2010) found that concentrating Nitroform on the inner half of the root zone produced greater caliper growth and chlorophyll than broadcasting across the full drip line. For mature trees, weight application toward the trunk side of the canopy. Keep granules off the trunk itself. For more on tree-specific fertility, see Best Fertilizer for Fruit Trees.
Sources: ANSI A300 Part 2 / ISA Best Management Practices for Tree & Shrub Fertilization (Smiley et al. 2002); Watson 2010 (Arboriculture & Urban Forestry, Morton Arboretum green ash study); Khatamian, Pair & Carrow 1984 (Journal of Arboriculture, Kansas State University honeylocust study); Greenway Biotech / Nitroform manufacturer label.
Container Nursery & Ornamentals
Quick answer: Preplant mix: 2–4 lb of Nitroform per cubic yard of growing medium. Maintenance: ~½ tsp per 4-inch pot or ~1 tsp per 6-inch pot. Univ. of Florida IFAS BMP work recommends the lower end paired with controlled irrigation to minimize nitrate leaching.
| Application | Rate | Source | Notes |
|---|---|---|---|
| Preplant incorporated into growing medium | 2–4 lb / cubic yard | Greenway Biotech / Nitroform label; Univ. of Florida IFAS BMP | Use the lower end (~2 lb / yd³) with controlled irrigation to minimize leaching |
| Maintenance, 4″ pot | ~½ tsp per pot | Greenway Biotech / Nitroform label | Sprinkle on the soil surface or mix into the top inch; water in |
| Maintenance, 6″ pot | ~1 tsp per pot | Greenway Biotech / Nitroform label | Reapply every 8–10 weeks during active growth |
| Larger landscape ornamentals (in-ground) | 3–4 lb / 1,000 sq ft | Greenway Biotech / Nitroform label | Broadcast and lightly rake in; water in thoroughly |
Leaching note: Univ. of Florida IFAS work (Chen, Huang & Caldwell 2001) documents that conventional container nursery fertilization rates often exceed plant requirements, with up to 50% of applied N lost to leaching or runoff. Using the lower end of the preplant range (~2 lb / yd³) combined with controlled irrigation is the IFAS-recommended approach.
Sources: University of Florida IFAS Extension (Chen, Huang & Caldwell 2001, ornamental container BMP); Greenway Biotech / Nitroform manufacturer label.
Vegetables & Field Crops
Quick answer: For typical vegetable N targets near 100 lb N per acre, that's roughly 256 lb of Nitroform per acre (~5.9 lb per 1,000 sq ft), broadcast and incorporated preplant. Most extension agronomists recommend pairing Nitroform with a quick-release N source on annual vegetables — do not use it alone.
| Application | Rate | Source | Notes |
|---|---|---|---|
| Field vegetables, ~100 lb N/acre target | ~256 lb / acre (~5.9 lb / 1,000 sq ft) | Penn State Ext.; Greenway Biotech label | Broadcast & incorporate preplant; pair with a quick-release N source on annual crops |
| Garden beds (preplant, top 2–3″) | 4–6 lb / 1,000 sq ft | Greenway Biotech label | Work into top 2–3 inches of soil before transplanting; water in |
| Per-plant side dress | 1–2 Tbsp per plant | Greenway Biotech label | Keep granules 3–4 inches from stems; water in |
| Pasture / forage / row-crop maintenance | 130–220 lb / acre | Greenway Biotech label | Adjust to soil test and crop removal; not a substitute for soluble N on grain crops |
📋 Soil test first: Field crop application rates above are general guidelines based on typical soil test levels and crop removal estimates. Actual rates should be confirmed by a current soil test and consultation with your local cooperative extension service, as needs vary significantly by soil type, crop variety, irrigation regime, and regional conditions.
First-year recovery caveat: Penn State Extension explicitly notes that the first one to two years of Nitroform use produce lower nitrogen recovery than quick-release sources. On short-cycle annual vegetables, use Nitroform as part of a blend with a quick-release N source (urea or ammonium sulfate) — do not rely on Nitroform alone to drive annual crop yield.
Sources: Penn State Extension Center for Turfgrass Science (ureaform performance documentation); Greenway Biotech / Nitroform manufacturer label.
06 / How to use
From bag
to soil.
Nitroform is a soil-applied granular product. Spread evenly, water in thoroughly, and let soil microbes do the metering. The calculator on the right converts your area or tree count into the exact pounds you need — and recommends the closest bag size.
-
1
Measure your area or count your trees.
For turf, get square footage. For trees, count the number of trees and estimate caliper or canopy diameter. For containers, count pots and note size. Plug these into the calculator at right.
-
2
Choose the right rate for the job.
Use the maintenance turf rate (2.6–5.1 lb / 1,000 sq ft) for lawns; the ANSI A300 rate (~6.6 lb / 1,000 sq ft of root-zone area) for established trees; the ~0.5 lb-per-tree planting rate for new bare-root transplants.
-
3
Spread evenly.
Use a broadcast or drop spreader for turf and large beds. For trees, broadcast around the drip line — or, for greater caliper response, concentrate on the inner half of the root zone (per Watson 2010). Avoid piling against trunks or stems.
-
4
Water in thoroughly.
Apply about ½ inch of irrigation within 24 hours of application. This moves the granules into contact with the soil microorganisms that release the nitrogen, and prevents granule loss to wind or foot traffic.
-
5
Reapply every 8–12 weeks during active growth.
Time the next application to match observed response — color, growth rate, soil temperature. In warm-moist conditions the curve runs closer to 8–10 weeks; in cool or dry conditions, closer to 10–12 weeks.
07 / Compare
Six nitrogen sources.
Different jobs.
Nitrogen sources differ in concentration, release rate, salt index, and burn risk. The comparison below shows where Nitroform fits relative to the other Greenway Biotech nitrogen options. For a deeper survey, see Best Nitrogen Fertilizer.
| Product | % N | Release | Burn risk | Best for | Notes |
|---|---|---|---|---|---|
| Nitroform 39-0-0 (this product) | 39% | Slow, 8–12 wks (microbial) | Very low | Turf, trees, container nursery, ornamentals | ~73% water-insoluble N; not for fast correction |
| Urea 46-0-0 | 46% | Fast, 1–3 wks (soluble) | Moderate | Large-area broadcast, cost-effective N per lb | Volatilization risk if not watered in; not foliar-safe at agricultural grade |
| Ammonium Sulfate 21-0-0 | 21% | Fast, 1–3 wks (soluble) | Moderate | Acid-loving plants, alkaline soils, lawn quick green-up | Adds 24% sulfur; mildly acidifying |
| Feather Meal 12-0-0 | 12% | Very slow, 3–4 mo (microbial) | Very low | Organic programs, perennials, orchards | OMRI-pathway organic; even slower curve than Nitroform |
| Blood Meal 13-0-0 | 13% | Moderate, 4–6 wks (microbial) | Low–moderate | Organic quick-fix for N deficiency, leafy crops | Animal-origin; not for hydroponics |
| Calcium Nitrate 15.5-0-0 | 15.5% | Immediate (water-soluble nitrate) | Low at use dilution | Hydroponic systems, transplant drench, fruiting crops | Also supplies 19% calcium; standard hydroponic N source |
08 / Decision
Is Nitroform the right
nitrogen source for you?
Nitroform earns its place when you want sustained feeding with low burn risk on perennial plantings. It is not a one-size-fits-all nitrogen source — for short-cycle annuals or fast deficiency correction, a quick-release N source is a better fit.
Best Choice For
- Cool- and warm-season turf programs that already budget slow-release N
- Established trees, shrubs, and orchards on ANSI A300 / ISA BMP fertility schedules
- Newly planted bare-root or B&B trees needing safe at-planting N
- Container nursery and high-value ornamentals where N leaching is a concern
- Custom blends where you want the slow-release N component to be high-purity and dust-free
- Landscape professionals who want fewer applications per season at lower burn risk
- Environmentally sensitive sites near waterways where leaching minimization is a goal
Consider Another Product If
- You need an immediate green-up or fast deficiency correction — try Ammonium Sulfate 21-0-0 or Urea 46-0-0
- You need an organic-program nitrogen source — try Feather Meal 12-0-0 or Blood Meal 13-0-0
- You also need sulfur with your N — Ammonium Sulfate 21-0-0 provides 24% sulfur
- You're running a hydroponic or fertigation system — Nitroform is granular and not water-soluble; use Calcium Nitrate 15.5-0-0 instead
- Soil temperatures will stay below 50°F — microbial release will be minimal; wait for warmer soil or use a soluble source
- You're fertilizing short-cycle annual vegetables alone — first-year recovery is lower; pair with a quick-release source or use a soluble N
09 / Build the program
Nitroform is the slow-release N.
These complete the program.
Nitroform supplies nitrogen only. For a balanced fertility program, pair it with phosphorus, potassium, and (when needed) a quick-release N companion. The four products below cover most use cases.
Granular Phosphate
MAP 11-52-0 (Granular)
Soil-applied granular phosphate that blends cleanly with Nitroform for a custom NPK mix. 11% N and 52% available phosphate (P₂O₅) for root development and flowering.
Potassium + SulfurPotassium Sulfate 0-0-53
53% soluble potash (K₂O) plus 17% sulfur, chloride-free. Adds the K and S that Nitroform doesn't supply — ideal for fruit and quality-sensitive crops.
K + Mg + SK-Mag 0-0-22
22% K₂O, 11% Mg, 22% S in one product. Pairs with Nitroform on magnesium-deficient turf, orchards, and ornamental beds.
Quick-Release NAmmonium Sulfate 21-0-0
Fast-acting nitrogen plus 24% sulfur for immediate green-up. Pair with Nitroform during the establishment phase when first-year ureaform recovery is still ramping up.
10 / Safety & handling
Read this before
you spread.
Nitroform is not classified as hazardous under OSHA HCS, but it is still a chemical fertilizer. Follow these handling rules every time. Refer to the Safety Data Sheet (SDS) for complete information.
- PPE: Wear gloves and safety eyewear when handling. Use a dust mask (N95 or better) when working in enclosed spaces or windy conditions. Wash hands and forearms thoroughly after handling.
- Storage: Store in the original sealed container in a cool, dry, well-ventilated area. Keep away from direct sunlight, heat, food, drink, and incompatible materials. The product can absorb moisture — reseal tightly after each use. Keep out of reach of children and pets.
- Application: Do not apply to waterlogged soils. Sweep granules off hard surfaces (sidewalks, driveways, hardscape) back onto soil. Do not apply near open water, wells, or storm drains. Water in within 24 hours to minimize surface runoff.
- Compatibility: Blends cleanly with most granular fertilizers (MAP, MKP, potassium sulfate, K-Mag, ammonium sulfate). Not water-soluble — do not use in fertigation, drip injectors, stock tanks, or foliar sprays. Use only as a soil-applied granular product.
- First aid: Eyes — flush with clean water for at least 15 minutes; seek medical attention if irritation persists. Skin — wash with soap and water; remove contaminated clothing. Ingestion — rinse mouth; do not induce vomiting; contact Poison Control (1-800-222-1222) or seek medical attention. Inhalation — move to fresh air; seek medical attention if symptoms persist.
11 / FAQ
Common questions.
Honest answers.
If your question isn't here, contact our team at questions@greenwaybiotech.com or call (562) 351-5168, Monday–Friday, 7 AM–5 PM PST.
What does the 39-0-0 NPK mean, and how much nitrogen is actually available?
The 39-0-0 means 39% nitrogen, 0% available phosphate (P₂O₅), and 0% soluble potash (K₂O). Of that 39% N, roughly 73% is water-insoluble nitrogen (WIN) — the slow-release fraction that soil microbes meter out over weeks. The remaining ~27% is water-soluble (urea and other soluble urea-formaldehyde reaction products) and becomes plant-available within the first one to two weeks after application. Total nitrogen released to plants over a full 8–12 week cycle is approximately 0.39 lb of actual N per pound of Nitroform applied.
How is the release rate controlled, and what affects it?
Release is driven by soil microbial activity, not by water solubility. Soil bacteria and fungi gradually break down the urea-formaldehyde polymer, releasing urea that is then hydrolyzed to ammonium and nitrified to nitrate. The dominant variable is soil temperature: very little release happens below 50°F, and release accelerates as soil warms above 55°F. Soil moisture, pH (6.0–7.0 is optimal), and overall microbial biomass also influence the rate. In warm, moist soils, expect a full 8–10 week feeding cycle; in cool or dry conditions, expect 10–12 weeks or longer.
Can I use Nitroform on newly planted trees?
Yes — this is one of Nitroform's best-documented use cases. Khatamian, Pair & Carrow (1984) at Kansas State University planted bare-root field-grown honeylocust transplants with 227 g (about ½ lb) of Nitroform mixed into the backfill, and reported greater trunk diameter than the unfertilized controls without burn injury. Doubling the rate to 454 g produced no additional growth benefit, so ½ lb per young (2–2.5 cm caliper) tree is a defensible upper bound for at-planting use. For larger B&B or container trees, use approximately 1 lb per gallon container or wrapped ball.
Why does Nitroform have lower first-year recovery than quick-release nitrogen?
Penn State Extension documents that ureaform sources like Nitroform produce lower nitrogen recovery in the first one to two years of use compared with quick-release sources such as urea or ammonium sulfate. The reason is microbial: the soil microbial community takes time to develop the enzymatic capacity to break down the urea-formaldehyde polymer at full pace. Once the microbial population is established, recovery improves substantially. Practical implication: in the first year of a Nitroform program, plan to either use the upper end of the recommended rate range or pair Nitroform with a quick-release N source contributing 25–50% of total N.
Can Nitroform be used in a hydroponic system or as a foliar spray?
No. Nitroform is not water-soluble — only about 27% of its nitrogen is water-soluble at room temperature, and the bulk of the product (the slow-release WIN fraction) will not dissolve in irrigation water or stock solutions. It will clog drip emitters, foul recirculating reservoirs, and provide little usable nitrogen on foliar contact. For hydroponics, use Calcium Nitrate 15.5-0-0. For foliar feeding, use a fully water-soluble fertilizer. Nitroform is intended exclusively as a soil-applied granular product.
What does the research say about where to apply Nitroform around a tree?
Watson (2010, Arboriculture & Urban Forestry) compared broadcasting Nitroform across the full dripline against concentrating it on the inner half of the root zone in green ash. Concentrating the application near the trunk side of the canopy produced greater caliper growth and higher leaf chlorophyll than the broadcast treatment. For mature established trees, weighting the application toward the inner root zone is supported by the data. Keep granules off the trunk itself, and water in thoroughly. For more on tree-specific fertility programs, see Best Fertilizer for Fruit Trees.
How does Nitroform compare to organic slow-release options like feather meal or blood meal?
All three rely on soil microbial activity for release, but they differ in concentration, release curve, and certification status. Nitroform (39% N) has the highest N concentration of the three and a curve of roughly 8–12 weeks. Feather meal (12% N) has the slowest release of any common nitrogen source — 3–4 months — and is acceptable for organic programs. Blood meal (13% N) has a moderate release curve of 4–6 weeks and is also organic. Choose Nitroform for the highest N concentration and conventional programs; choose feather or blood meal for organic programs.
Is Nitroform OMRI listed or acceptable for organic production?
No. Nitroform is a synthetic urea-formaldehyde product and is not approved for certified organic production under USDA NOP standards. For certified organic programs, use Feather Meal 12-0-0, Blood Meal 13-0-0, or Bone Meal 3-15-0 for nitrogen and phosphorus respectively.
What is the salt index, and is fertilizer burn really a non-issue?
Because most of Nitroform's nitrogen is water-insoluble, it doesn't spike the soil solution's salt concentration the way a soluble salt fertilizer can. The salt index of urea-formaldehyde products is substantially lower than that of urea, ammonium sulfate, or potassium chloride. That said, “low burn risk” is not the same as “zero burn risk.” At very high rates, on extremely dry soils, or when granules are concentrated against stems, root contact, or in container media, injury is still possible. Stick to label rates, water in promptly, and keep granules off direct contact with plant tissue.
How is Nitroform tested for heavy metals?
Every production lot is independently lab tested for heavy metal content using third-party analytical labs. Results are consistently well below the limits required for CDFA fertilizer registration. Heavy metal analysis reports for specific lots are available on request — contact questions@greenwaybiotech.com.
Ready to feed?
Pick your bag. We'll ship it.
Bag sizes from 1 lb to 50 lb to fit everything from a single tree to a small commercial operation. Free shipping on orders over $100 in the continental US. 90-day money-back guarantee on every product.
Choose your size →