Nitroform 39-0-0 Slow-Release Nitrogen Fertilizer
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Slow-release nitrogen · 39-0-0
About Nitroform 39-0-0
Nitroform 39-0-0 is a ureaform (urea-formaldehyde) fertilizer: a dry, blue-colored nitrogen source in which most of the nitrogen is bound in methylene urea polymers that soil microbes break down over a period of months. It guarantees 39% total nitrogen and no phosphate or potash, and it is spread on the soil and watered in, never dissolved or sprayed. Use it as the slow-release nitrogen in a lawn, tree, shrub, or ornamental-bed program. Its most important limitation: release depends on warm, biologically active soil, so it feeds slowly in cold soil and is a poor choice for quick correction, for hydroponics or fertigation, and for short-season annual vegetables.
- 0.39 lb N per lb Each pound of product supplies 0.39 lb of nitrogen; 2.6 lb of Nitroform delivers 1 lb of nitrogen
- 1.3–2.6 lb / 1,000 sq ft Lawn rate per application (0.5–1 lb N); trees and shrubs 2.6–5.1 lb per 1,000 sq ft of root zone per application
- 1–50 lb bags Six sizes; the calculator below finds the lowest-price in-stock bags for your lawn area or root-zone area
Product facts & composition
| Specification | Detail |
|---|---|
| Total nitrogen (N) | 39% |
| Nitrogen breakdown (label) | 3% urea nitrogen, 7.5% other water-soluble nitrogen, 28.5% water-insoluble nitrogen. About 73% of the total nitrogen is water-insoluble. |
| Available phosphate (P₂O₅) | 0% |
| Soluble potash (K₂O) | 0% |
| Derived from | Urea-formaldehyde (methylene urea polymers) |
| Fertilizer class | Ureaform. The AAPFCO definition requires at least 35% nitrogen with at least 60% of that nitrogen water-insoluble; this product meets both. |
| Physical form | Dry, blue, odorless solid (safety data sheet). Applied dry to the soil surface or mixed into soil; not a soluble fertilizer. |
| Release characteristic | Microbial. Soil microbes break the polymer down to urea, which is then converted to ammonium and nitrate. Very little nitrogen is released while soil is below about 50°F; release speeds up as soil warms (Cornell University turfgrass BMP). Feeding continues for roughly two to three months or longer in a growing season. |
| Package sizes | 1 lb, 2 lb, 5 lb, 10 lb, 20 lb, and 50 lb (shipped as 2 × 25 lb bags) |
| Packaged by | Greenway Biotech, Inc., Madera, California |
The analysis is stated as N–P₂O₅–K₂O, the standard fertilizer-label basis, and percentages are by weight of product: 1 lb of Nitroform contains 0.39 lb of nitrogen, and a 10 lb bag contains 3.9 lb. The water-soluble portion (about 10.5% of the product by weight as nitrogen) behaves like a modest dose of soluble nitrogen in the first weeks; the water-insoluble portion (28.5%) is the slow-release reserve. Nitroform supplies nitrogen only, so phosphorus, potassium, sulfur, and other nutrients come from a soil test and separate products.
Best uses & benefits
Nitroform earns its place where you want nitrogen delivered steadily over a season to established perennial plantings, with less soluble salt and less leaching than the same nitrogen applied as urea or ammonium sulfate. It is not a one-size nitrogen source.
Established lawns
Extension lawn programs recommend slowly available nitrogen for a large share of the annual nitrogen, and Virginia Cooperative Extension permits higher single applications when at least half of the nitrogen is slowly available. Nitroform, at 73% water-insoluble nitrogen, qualifies. Apply during active growth in soil above 50°F: late summer through fall and lightly in spring for cool-season grasses, after full green-up through summer for warm-season grasses.
Established trees and shrubs
Clemson, Purdue, and University of New Hampshire Extension all favor slow-release nitrogen for woody plants because it feeds evenly over months and lowers the risk of root injury. Broadcast it over the root zone to the drip line and water it in; split the yearly amount between spring and early fall.
Ornamental beds and ground covers
Perennial beds, hedges, and ground covers get the same steady feeding as shrubs. Use the tree-and-shrub rate on a bed-area basis and keep the granules off foliage and crowns.
The slow-release part of a blend
Because it carries 39% nitrogen, a small weight of Nitroform adds a lot of slow-release nitrogen to a dry blend with a granular phosphate or potash source. Blend only what you will spread the same day, and weigh each component.
Where it is a poor fit
- Fast correction of pale, nitrogen-hungry turf or plants. Only about a quarter of the nitrogen is water-soluble; the rest waits on microbes. Use Ammonium Sulfate 21-0-0 or Urea 46-0-0 for a quick response.
- Cold soil. Below about 50°F microbial release nearly stops, so an application to cold soil sits until the soil warms. It is not a dormant-season feed.
- Hydroponics, fertigation, drip injection, and foliar sprays. The product does not dissolve as a whole and will foul reservoirs and emitters. Use a fully soluble source such as Calcium Nitrate 15.5-0-0.
- Short-season annual vegetables. Spring soil is often too cool for the release curve to match early crop demand, and no vegetable rate is published for this product; use a soluble or quick-release nitrogen source.
- Newly planted trees and shrubs. Purdue and Clemson Extension advise against fertilizing at planting; water instead, and begin feeding the following season.
- Certified organic programs. Nitroform is a synthetic material and is not allowed under USDA organic standards. See Feather Meal 12-0-0 or Blood Meal 13-0-0.
Application rates & directions
All rates below are product weight, spread evenly over the soil surface and watered in. They are derived from university Extension nitrogen recommendations applied to this product’s 39% nitrogen guarantee, plus the manufacturer’s labeled lawn rate. Base any program on a soil test where one is available, and start at the lower end of a range.
Weigh, do not scoop. No spoon or cup measure is published for this product because the weight of a given volume has not been measured. A kitchen or postal scale is the accurate tool: 1.3 lb is about 21 oz; 2.6 lb is about 42 oz.
Lawns
| Rate | Product per 1,000 sq ft | Nitrogen delivered | When to use it | Basis |
|---|---|---|---|---|
| Starting rate | 1.3 lb (about 21 oz) | 0.5 lb N per 1,000 sq ft | Low-maintenance lawns, sandy soil, first use of the product, or any application where a state cap applies | UC IPM: 0.5–1 lb N per 1,000 sq ft per application, low end |
| Manufacturer’s labeled lawn rate | 2.2 lb (about 35 oz) | 0.86 lb N per 1,000 sq ft | Typical maintenance feeding of established turf during active growth | Nitroform 39-0-0 label: 0.86 lb N (2.22 lb product) per 1,000 sq ft; also the maximum in MD, NH, NJ, and VA |
| Full rate | 2.6 lb (about 42 oz) | 1 lb N per 1,000 sq ft | Higher-maintenance lawns in the main growth season; no more than this per application | UC IPM: no more than 1 lb N per 1,000 sq ft per application |
Timing and frequency. UC IPM notes that slow-release fertilizers may feed for up to 8 weeks and suggests applying them at 6–8 week intervals during active growth. Annual totals depend on grass species and how the lawn is managed: UC IPM gives 4–6 lb N per 1,000 sq ft per year for a well-maintained lawn, and many species and low-maintenance lawns need less, so match the number of applications to your lawn’s annual target rather than to the bag, and never exceed 1 lb N (2.6 lb of product) in a single application. Virginia Cooperative Extension allows up to 1.5 lb N per application for programs in which at least half the nitrogen is slowly available, but only for specific species and seasons; follow your state Extension program. Cool-season lawns take most of their nitrogen from late summer through fall; warm-season lawns are fed after full green-up through summer and not within about six weeks of the first frost.
Lawn limits. Apply only to actively growing grass in soil above about 50°F; do not apply to frozen or dormant turf, ahead of heavy rain, or near water, storm drains, or ditches, and sweep any product off pavement back onto the lawn. Several states regulate lawn nitrogen: the manufacturer’s label caps applications at 0.86 lb N per 1,000 sq ft in Maryland, New Hampshire, New Jersey, and Virginia. Water in soon after spreading and avoid mowing until it has been watered in.
Established trees, shrubs, and ornamental beds
| Rate | Product per 1,000 sq ft | Nitrogen delivered | Timing | Basis |
|---|---|---|---|---|
| Standard, per application | 2.6 lb | 1 lb N per 1,000 sq ft | Once in spring as growth begins, and once more in early fall if a second feeding is wanted | Purdue HO-140: 1–2 lb N per 1,000 sq ft per application, split spring and fall, low end |
| Higher, per application | 5.1 lb | 2 lb N per 1,000 sq ft | Same timing; use only where faster growth is wanted on an established, unstressed plant | Purdue HO-140 high end; UNH Extension: above 2 lb N only from slow-release sources |
| Annual total | 5.1–10.3 lb per year | 2–4 lb N per 1,000 sq ft per year | Sum of all applications in a year | Clemson HGIC 1000: 2–4 lb N per 1,000 sq ft per year from slow-release sources; Purdue HO-140: 2–4 lb |
Where to spread it. Fertilize the root zone, not the trunk: Clemson recommends the area out to the drip line, and Purdue the band from half the canopy radius out to half a radius beyond the drip line. For a narrow-canopied tree, Clemson estimates the root-zone radius in feet as 1 to 1.5 times the trunk diameter in inches. Root-zone area in square feet is 0.785 × canopy diameter (ft) × canopy diameter (ft); a tree with a 16 ft canopy has about 200 sq ft of root zone and needs about 0.5 lb of Nitroform at the standard rate. Where the root zone is lawn, count that nitrogen toward the lawn’s total.
Tree and shrub limits. Do not fertilize at planting or in the first growing season (Purdue, Clemson); water new plantings instead. Where the root zone is lawn, keep any single application to 1 lb N per 1,000 sq ft (Colorado State University Extension) and count it toward the lawn’s total. Do not fertilize drought-stressed plants, plants with root damage, or plants that are growing poorly without a confirmed nutrient need. Avoid mid-summer applications in cold-winter regions, which can delay hardening. Keep the product off foliage, crowns, and trunks.
Uses without a published rate
This page does not give rates for container nursery mixes, vegetable gardens, field crops, pastures, or houseplants. The manufacturer’s lawn rate and the Extension sources above cover turf and landscape plantings only, and we will not extend those numbers to other crops without evidence. If you grow in containers, Extension nursery guidance favors controlled-release fertilizers designed for container media.
How to use Nitroform 39-0-0
- Check the need and the season. Confirm the lawn or planting is actively growing and the soil is above about 50°F. A soil test every 2–3 years sets the nitrogen program; do not feed stressed or newly planted trees.
- Measure the area. Lawn: length × width in feet. Trees and shrubs: canopy diameter × canopy diameter × 0.785 for each plant, or the bed area. The calculator below turns the area into pounds of product.
- Weigh the product. 1.3 lb per 1,000 sq ft of lawn to start (up to 2.6 lb), or 2.6 lb per 1,000 sq ft of root zone for trees and shrubs. Use a scale; volume measures are not published for this product.
- Spread evenly. Use a rotary spreader for lawns and large beds and calibrate it on a measured strip first. Around trees, broadcast over the root zone by hand or spreader and keep it off the trunk. Sweep any product off hard surfaces.
- Water in. Irrigate soon after spreading so the product moves into the soil where microbes release it, then wait for the response before deciding on the next application: 6–8 weeks for lawns, the next season for trees.
Calculator & choosing a size
Formula: pounds of Nitroform = pounds of nitrogen wanted ÷ 0.39. At the lawn starting rate, area in sq ft × 0.0013 = pounds of product per application; at the full lawn rate or the standard tree rate, area × 0.0026. Multiply by the number of applications you plan this season.
Worked example: a 4,000 sq ft lawn at the starting rate needs 4,000 × 0.0013 = 5.2 lb per application, which delivers 2 lb of nitrogen. A 10 lb bag covers one application with 4.8 lb left toward the next; three applications need 15.6 lb, so a 20 lb bag covers the season. Three trees with 16 ft canopies have about 600 sq ft of root zone and need 600 × 0.0026 = 1.6 lb per application, so a 2 lb bag covers one feeding.
| Bag | Nitrogen in the bag | Lawn at 1.3 lb per 1,000 sq ft (starting rate) | Lawn or root zone at 2.6 lb per 1,000 sq ft (full rate) |
|---|---|---|---|
| 1 lb | 0.39 lb | 770 sq ft | 385 sq ft |
| 2 lb | 0.78 lb | 1,540 sq ft | 770 sq ft |
| 5 lb | 1.95 lb | 3,850 sq ft | 1,920 sq ft |
| 10 lb | 3.9 lb | 7,700 sq ft | 3,850 sq ft |
| 20 lb | 7.8 lb | 15,400 sq ft | 7,700 sq ft |
| 50 lb (2 × 25 lb) | 19.5 lb | 38,500 sq ft | 19,200 sq ft |
The calculator applies these rates automatically, shows the nitrogen you are adding, and recommends the lowest-price in-stock bag combination that covers the amount and, when different, the combination with the least left over. Tax and shipping are calculated at checkout.
The calculator needs JavaScript. If it does not appear, use the formula and coverage table above to choose a size.
How it works
Ureaform is made by reacting urea with formaldehyde. The reaction links urea molecules into methylene urea chains of different lengths: short chains dissolve in water and are available within days, and longer chains are insoluble and must be broken down by soil bacteria and fungi before their nitrogen is released. In Nitroform the water-insoluble chains carry about 73% of the nitrogen, which is why the product is classified as a ureaform under the AAPFCO definition (at least 35% N, at least 60% of it water-insoluble). Cornell University’s turfgrass BMP guidance describes the sequence: microbes release urea from the polymer, urease converts it to ammonium, and nitrifying bacteria convert ammonium to nitrate, the forms roots take up. How soil microbes affect plant health explains the organisms doing that work.
Because microbes do the metering, soil temperature and moisture set the pace. Little nitrogen is released below about 50°F, and release accelerates as soil warms, which makes the supply track the growth of turf and woody plants through a season and leaves less nitrate exposed to leaching after heavy rain than a soluble source would. The same dependence is the product’s limitation: cold, dry, or biologically poor soil slows it, and the most resistant fraction can carry over into the next season rather than feeding this one. Because most of the nitrogen is not in solution, the product raises the soil’s salt concentration far less than the same nitrogen as urea or ammonium sulfate, and Virginia Cooperative Extension notes that properly applied slowly available sources reduce the chance of foliar burn. Low risk is not zero risk: over-application, piles against stems, and dry soil can still injure plants.
Published tree research fits this picture without overselling it. At Kansas State University, bare-root honeylocust planted with 227 g (0.5 lb) of Nitroform in the backfill had greater trunk diameter than unfertilized trees by the second season, and doubling the amount added nothing (Khatamian, Pair, and Carrow, 1984). At the Morton Arboretum, three years of broadcast Nitroform on established green ash at about 3.9 lb N per 1,000 sq ft per year produced only limited responses on a moderately fertile site: a caliper gain in the third year for trees fertilized over the inner root zone at the full rate, with no difference in twig growth or leaf area (Watson, 2010). The lesson from both is that slow-release nitrogen helps where nitrogen is actually limiting, that more is not better, and that a soil test is a better guide than a calendar. These studies concern the ingredient and this product’s brand of ureaform; they are not trials of the Greenway package, and current Extension guidance still advises against fertilizing at planting. For a broader survey of nitrogen sources and where each fits, read best nitrogen fertilizer for your garden, lawn, and hydroponics.
Compare your options
Nitrogen sources differ in concentration, how fast the nitrogen becomes available, how much soluble salt they add, and whether they suit organic programs. Analyses below are each product’s label guarantee. For what nitrogen does in the plant and how to read deficiency symptoms, see the function of nitrogen in plants.
| Product | Analysis | How the nitrogen becomes available | Choose it when | Limitation |
|---|---|---|---|---|
| Nitroform 39-0-0 (this product) | 39-0-0; 73% of N water-insoluble | Microbial breakdown over months; slow in soil below 50°F | Season-long feeding of lawns, trees, shrubs, and beds with low burn risk | Not for quick correction, cold soil, hydroponics, or organic programs |
| Urea 46-0-0 | 46-0-0 | Soluble; available within days once converted in soil | Lowest cost per pound of nitrogen for large areas | Can lose nitrogen as ammonia if left on a dry surface; higher burn risk |
| Ammonium Sulfate 21-0-0 | 21-0-0, 24% sulfur | Soluble; fast | Quick green-up; sulfur; acid-loving plants or high-pH soil | Acidifies soil over time; higher burn risk at equal nitrogen |
| Calcium Nitrate 15.5-0-0 | 15.5-0-0, 19% calcium | Soluble nitrate; immediate | Hydroponics, fertigation, and calcium-demanding crops | Not a slow-release source; keep out of concentrated phosphate or sulfate stock tanks |
| Feather Meal 12-0-0 | 12-0-0 | Microbial; slow, over months | Organic programs needing slow nitrogen | About a third of Nitroform’s nitrogen per pound; also slow in cold soil |
| Blood Meal 13-0-0 | 13-0-0 | Microbial; faster than feather meal | Organic programs needing a quicker nitrogen response | Attracts animals; can burn if over-applied |
Handling, storage & limitations
- Classification. The safety data sheet classifies Nitroform 39-0-0 as not hazardous under the OSHA Hazard Communication Standard and not regulated for transport. It is still a fertilizer: keep it out of reach of children and pets, and do not eat, drink, or smoke while handling it.
- Dust, eyes, and skin. The SDS lists the product as a possible eye irritant. Wear gloves and safety eyewear when handling, avoid raising dust in enclosed spaces, and wash hands, forearms, and face after use and before eating.
- Storage. Keep the bag sealed in its original container in a cool, dry, ventilated place, protected from direct sunlight and away from food, drink, and incompatible materials. Reseal after each use and do not store in unlabeled containers.
- Environment. Do not apply near water, storm drains, or drainage ditches, ahead of heavy rain, or to frozen ground. Sweep spills and any product on pavement back onto the soil rather than hosing them into a drain. Follow your state’s lawn-fertilizer rules.
- Use limitations. Soil application only: not for hydroponics, fertigation, drip or foliar use. Not for certified organic production. No published rate for containers, vegetables, or field crops. Do not exceed 1 lb N (2.6 lb of product) per 1,000 sq ft in one lawn application, and do not fertilize newly planted or stressed trees.
- First aid (from the SDS). Eyes: flush with plenty of water for at least 15 minutes and get medical attention if symptoms occur. Skin: flush with water and remove contaminated clothing. Inhalation: move to fresh air. Ingestion: rinse the mouth with water, do not induce vomiting unless directed by medical personnel, and contact Poison Control at 1-800-222-1222.
Frequently asked questions
What does 39-0-0 mean, and how much of the nitrogen is slow-release?
39-0-0 means 39% total nitrogen, 0% available phosphate (P₂O₅), and 0% soluble potash (K₂O), by weight of product. The label breaks the nitrogen down as 3% urea nitrogen, 7.5% other water-soluble nitrogen, and 28.5% water-insoluble nitrogen, so about 73% of the nitrogen is the slow-release fraction and about 27% is available quickly. Each pound of product supplies 0.39 lb of nitrogen; 2.6 lb supplies 1 lb.
How long does one application feed, and what controls the release?
Soil microbes, not water, release the nitrogen, so soil temperature and moisture control the pace. Very little is released below about 50°F; release speeds up as soil warms. In a growing season an application feeds for roughly two to three months, and UC IPM suggests reapplying slow-release lawn fertilizers at 6 to 8 week intervals during active growth. The most resistant fraction can carry into the following season.
Will it burn my lawn or plants?
The risk is low at the rates on this page because about three quarters of the nitrogen is water-insoluble and does not raise the soil solution's salt concentration the way urea or ammonium sulfate does; Virginia Cooperative Extension notes that properly applied slowly available sources reduce the chance of foliar burn. Low is not zero: stay within 1 lb of nitrogen (2.6 lb of product) per 1,000 sq ft per lawn application, keep it off foliage and trunks, do not pile it against stems, and water it in.
When should I apply it to a lawn?
Only while the grass is actively growing and the soil is above about 50°F. Cool-season lawns (fescue, bluegrass, ryegrass) take most of their nitrogen from late summer through fall with a light spring feeding; warm-season lawns (bermuda, zoysia, St. Augustine) are fed after full green-up through summer and not within about six weeks of the first frost. Applying to cold or dormant turf wastes the product and risks runoff.
Can I use it in hydroponics, a drip system, or as a foliar spray?
No. Only the small water-soluble fraction dissolves; the slow-release fraction stays solid, so the product will foul reservoirs and clog emitters and gives little benefit on leaves. It is a soil-applied product. For hydroponics or fertigation use a fully soluble nitrogen source such as Calcium Nitrate 15.5-0-0.
Should I put Nitroform in the planting hole for a new tree?
We do not recommend it. Purdue and Clemson Extension advise against fertilizing trees and shrubs at planting, and University of New Hampshire Extension notes that quickly available fertilizer at planting can inhibit root growth; the priority is water and root establishment. A 1984 Kansas State study did find that honeylocust planted with 0.5 lb of Nitroform in the backfill grew larger trunks than unfertilized trees without injury, and that doubling the amount added nothing, but that was a research treatment on one species, not a consumer direction. Begin feeding the season after planting at the tree and shrub rates above.
Is Nitroform organic or OMRI Listed?
No. Nitroform is a synthetic urea-formaldehyde product and is not permitted in certified organic production. For organic programs use Feather Meal 12-0-0 for slow nitrogen or Blood Meal 13-0-0 for a faster organic response.
How does it compare with feather meal or blood meal?
All three depend on soil microbes, so all three are slow in cold soil. Nitroform carries 39% nitrogen, about three times feather meal (12%) or blood meal (13%), so far less product is needed per pound of nitrogen, and it is a conventional, not organic, material. Feather meal releases slowly over months and blood meal faster; both are allowed in organic programs, and both can attract animals, while Nitroform is odorless.
Can I mix it with other fertilizers?
In a dry blend, yes: weigh each granular component, blend only what you will spread that day, and apply the blend at the rate set by the most restrictive component. Never add Nitroform to a tank mix, injector, or reservoir. On a lawn, pairing it with a soluble source such as Ammonium Sulfate 21-0-0 gives a quick response while the slow-release fraction builds; count both toward your per-application and annual nitrogen limits.
Related guides & articles
- Best Fertilizer for Lawns: Rates, Timing, and Iron by Grass Type: annual nitrogen targets by grass species, per-application limits, seasonal timing for cool- and warm-season lawns, and where slow-release nitrogen fits in the program.
- Best Nitrogen Fertilizer for Your Garden, Lawn, and Hydroponics: how urea, ammonium sulfate, calcium nitrate, Nitroform, and the organic meals differ in speed, cost per pound of nitrogen, and best use.
- What Is the Function of Nitrogen in Plants?: what nitrogen does, how to tell nitrogen deficiency from iron, sulfur, and potassium problems, and why over-feeding causes its own trouble.
Product documents & sources
- Safety Data Sheet, Nitroform 39-00-00 (PDF): hazard communication, handling, storage, and first aid for all package sizes; issued July 2019. It documents the product’s safety profile, not application rates.
- The current package label is available by email from questions@greenwaybiotech.com. If the directions printed on your bag differ from the weight-based rates on this page, use the rates here.
Sources used for the rates and statements on this page
- UC IPM, Lawn Maintenance: Amount of Fertilizer: 0.5–1 lb N per 1,000 sq ft per application and no more than 1 lb; 4–6 lb N per year for maintained lawns; slow-release products reapplied at 6–8 week intervals (basis of the lawn rates).
- Virginia Cooperative Extension 430-011, Lawn Fertilization in Virginia: urea formaldehyde as a slowly available source; higher per-application allowances when at least 50% of nitrogen is slowly available; reduced foliar-burn risk.
- Penn State Extension, Enhanced Efficiency Nitrogen Fertilizers for Turfgrasses: methylene urea and ureaform products, 30–40% N, and why the water-insoluble nitrogen percentage on the label matters.
- Cornell University, New York State Golf Course BMPs, Nitrogen Fertilizer Use (PDF): AAPFCO ureaform definition (at least 35% N, at least 60% WIN), microbial release pathway, and little release below 50°F.
- Clemson HGIC 1000, Fertilizing Trees and Shrubs: 2–4 lb N per 1,000 sq ft per year from slow-release sources, not to exceed 6; area to the drip line; root-zone radius from trunk diameter; do not fertilize new or drought-stressed plants.
- Purdue Extension HO-140-W, Fertilizing Woody Plants (PDF): 2–4 lb N per 1,000 sq ft per year split 1–2 lb in spring and fall; urea formaldehyde as a slow-release source; feeder-root zone; no fertilizer at planting.
- University of New Hampshire Extension, Fertilizing Trees and Shrubs: 1–3 lb N per 1,000 sq ft, rates above 2 lb from slow-release sources only; prefer 30–50% water-insoluble nitrogen; quick-release fertilizer at planting not recommended.
- Colorado State University Extension, GardenNotes 651, Fertilizing Shade Trees (PDF): soil-organic-matter-based rates, per-application limit in lawn areas, and why stressed trees should not be fertilized.
- Watson, G. 2010. The Effect of Broadcast Nitrogen Fertilization Rates and Placement on the Growth of Green Ash Trees. Arboriculture & Urban Forestry 36(4):179–182: three-year Nitroform trial; limited responses; inner-root-zone placement.
- Khatamian, H., J.C. Pair, and R. Carrow. 1984. Effects of Turf Competition and Fertilizer Application on Trunk Diameter and Nutrient Composition of Honeylocust. Journal of Arboriculture 10(5):156–159: 227 g of Nitroform in the backfill increased trunk diameter; doubling did not.
- McVey, G.R. 1978. Methylene Urea: A Controlled Release Nitrogen Source for Turfgrasses (PDF, industry paper): water-insoluble fractions, reduced nitrification rate, and low salt index of methylene urea sources.
Rates and sources reviewed September 9, 2026.
Help choosing & next step
Not sure whether your lawn needs slow-release nitrogen, how to split a tree’s yearly amount, or which bag covers the season? Email questions@greenwaybiotech.com or call (562) 351-5168, Monday to Friday, 7 AM to 5 PM Pacific, with your area or soil test and we will work it out with you. Every order carries a 90-day satisfaction guarantee.
Ready to buy? Run the calculator to size your order, or choose a bag from the size selector at the top of this page.
Greenway Biotech, Inc. is a family-owned fertilizer company in Madera, California, blending and packaging specialty fertilizers since 1989.
