Newmarket, Ontario (Head Office)
1175 Stellar Drive, Unit #5
Newmarket, ON L3Y 7B8
- Mon10:00am–6:00pm
- Tue10:00am–6:00pm
- Wed10:00am–6:00pm
- Thu10:00am–6:00pm
- Fri10:00am–6:00pm
- Sat10:00am–4:00pm
- SunClosed
$0.00 CAD
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Jack's Classic Blossom Booster 10-30-20 is a Jack’s Classic blossom booster fertilizer and water soluble plant food made to promote more flowers and brighter colors.
Built around a high phosphorus formulation, this bloom fertilizer is suited to periods of bud set when plants are gearing up to flower. It’s designed to increase the number and size of blossoms, helping flowering displays look fuller and more finished. Gardeners also reach for it when they want brighter colors and a stronger bloom presence, especially for containers and other plantings where flower impact matters most.
This professional formula features a 10-30-20 NPK and is described as feeding through both the roots and the leaves, supporting consistent nutrient uptake in a range of growing situations. Alongside the core macronutrients, it’s a “with micronutrients” formula, including magnesium plus micronutrients such as iron, manganese, zinc, copper, boron, and molybdenum, with several provided in chelated forms.
Jack's Classic Blossom Booster 10-30-20 is positioned for indoor and outdoor plants, making it an easy match for seasonal gardens as well as year-round indoor growing. It’s intended for flowering plants and is commonly associated with popular bloomers like geraniums, impatiens, begonias, marigolds, hydrangea, bougainvillea, hibiscus, orchids, and violets. It’s also described as great for vegetables and fruit, including fruit trees and berry bushes, and it’s often chosen for flowering beds, containers, and hanging baskets where consistent bloom quality is the goal.
This is a good fit for growers who want a water soluble plant food that targets bloom development with a high phosphorus formulation, supports uptake through roots and leaves, and includes micronutrients for well-rounded flowering-plant nutrition.
Step-by-step mixing and feeding instructions for Jack's Classic Blossom Booster 10-30-20 - 1.5 lbs.
Fill your reservoir or watering container with clean, room-temperature water first. Shake the bottle of Jack's Classic Blossom Booster 10-30-20 - 1.5 lbs well before every use. Using the feeding schedule below, measure the recommended dose and add it directly to the water while stirring. Allow the solution to mix fully before adding any other fertilizers, additives, or supplements.
Always add nutrients to water — not the other way around. Mix thoroughly between products to ensure an even, stable nutrient solution.
Vegetative stage — Blossom Booster
Flowering stage — Blossom Booster
Warning – Important Safety Information
This product may cause mild skin irritation and eye irritation. Avoid unnecessary contact with skin, eyes, and clothing. Use only as directed.
General safety precautions
Read and follow all instructions on the product label and any accompanying documentation before use. Keep out of reach of children and pets. Do not ingest. Avoid breathing vapours, mist, or dust that may be generated during handling or use.
Wear appropriate personal protective equipment (PPE), such as protective gloves, long sleeves, long pants and closed-toe footwear. When there is a risk of splashing or airborne particles, use safety glasses or other suitable eye and face protection.
First aid – skin contact
IF ON SKIN OR HAIR: Remove contaminated clothing immediately. Rinse skin with clean water for several minutes, then wash with mild soap and water. If irritation or redness develops and persists, seek medical attention. Wash contaminated clothing before reuse.
First aid – eye contact
IF IN EYES: Rinse cautiously with clean water for several minutes, keeping eyelids open. Remove contact lenses if present and easy to do. Continue rinsing. If irritation persists, obtain medical advice.
First aid – ingestion and inhalation
IF SWALLOWED: Rinse mouth thoroughly with water. Do not induce vomiting unless instructed by a medical professional. Seek medical attention if you feel unwell.
IF INHALED: Move the person to fresh air and keep them comfortable for breathing. If coughing, breathing difficulty, dizziness or other symptoms occur, seek medical assistance.
Storage and handling
Store this product in its original closed container, in a cool, dry and well-ventilated area. Protect from extreme temperatures and direct sunlight. Keep container tightly sealed when not in use.
Avoid release to drains, natural waterways or outdoor soil. Dispose of unused product and empty containers in accordance with local regulations and the directions on the label.
Important: If medical advice is needed, keep the product label or container available. Always follow the specific instructions and safety recommendations provided by the manufacturer. This safety notice is intended as general guidance and does not replace official label directions or documentation.
| Total Nitrogen (N) | 10.0% |
|---|---|
| Ammoniacal Nitrogen (N) | 5.0% |
| Nitrate Nitrogen (N) | 5.0% |
| Available Phosphate (P2O5) | 30.0% |
| Soluble Potash (K2O) | 20.0% |
| Water Soluble Magnesium (Mg) | 0.5% |
| Boron (B) | 0.02% |
| Chelated Copper (Cu) | 0.05% |
| Chelated Iron (Fe) | 0.1% |
| Chelated Manganese (Mn) | 0.05% |
| Molybdenum (Mo) | 0.001% |
| Chelated Zinc (Zn) | 0.05% |
Ammoniacal Nitrogen (N) is a plant-available form of ammonium (NH₄⁺) that provides a steady, gentle source of nitrogen for healthy green growth. Unlike fast-release nitrogen types, ammoniacal nitrogen feeds plants slowly, helps stabilize root-zone pH, and works well in cooler temperatures. It is commonly used during early vegetative growth because it supports strong leaf development without burning young roots. If plants show pale leaves, slow growth, or weak stems, they may need more available ammoniacal nitrogen.
Even in tiny amounts, molybdenum is crucial because it helps plants convert absorbed nitrogen, especially nitrate, into forms they can actually use to build new growth. That makes ammonium molybdate unique from many other micronutrient sources: it supports nitrogen-use efficiency, so a shortage can make plants look nitrogen-deficient even when feeding is adequate, leading to slow growth, pale leaves, and weak vigor unless the bottleneck is fixed.
Available Phosphate (P₂O₅) supports root development, energy transfer, and early structural growth by providing a form of phosphorus that plants can absorb and use quickly.
Boric acid supplies boron, which plants need in extremely small amounts to build healthy new growth and support flowering and fruit development, but the safe range is very narrow. It’s unique because deficiency shows up first in the newest tissues while excess often burns older leaf edges, so accurate diagnosis and tiny, careful corrections matter more than with most nutrients.
Boron is essential because it stabilizes cell walls, supports root and shoot growth, and regulates sugar movement throughout the plant. What makes boron unique is its limited mobility and extremely narrow range between deficiency and excess, which causes new growth to show symptoms rapidly when levels fall out of balance.
Chelated copper is important because it supports key enzyme systems that drive energy flow, strong tissue formation, and healthy new growth, while chelation keeps copper available and stable in the root zone. It’s unique because plants need it in extremely small amounts and it can become unavailable or toxic more easily than many other micronutrients, so chelated forms help deliver precise, predictable copper without big swings.
Chelated iron is important because it keeps iron usable for plants even when growing conditions would normally lock iron out, helping prevent the classic yellow-new-leaf symptom caused by low chlorophyll production. It is unique from other iron sources because the chelation protects iron from becoming insoluble, making it a more reliable way to correct iron-related chlorosis when regular iron can fail.
Chelated manganese is important because it keeps manganese available for photosynthesis and enzyme activity even when pH or water chemistry would normally lock it out, and it’s unique from similar micronutrients because it strongly supports the plant’s energy-processing systems that drive healthy, resilient new growth.
Chelated zinc is important because it keeps zinc available for uptake even when pH or root-zone conditions would normally lock zinc out, helping plants form normal-sized, healthy new growth—something that makes zinc uniquely different from many other nutrients that mainly affect older leaves or simple leaf color changes.
Copper EDTA helps keep copper dissolved and available to roots longer, so plants can absorb it more consistently when copper would otherwise tie up in the growing medium. It’s important because copper supports enzyme activity and healthy new growth, and it’s unique because the chelate improves predictability while allowing very small, controlled copper dosing.
Molybdenum is important because it helps plants convert nitrogen into usable building blocks for chlorophyll and growth, and it’s unique from many nutrients because it mainly supports enzyme-driven “nutrient use” rather than directly building plant tissue.
Nitrate Nitrogen provides a stable, easy-to-absorb form of nitrogen that supports steady growth, strong foliage, and reliable plant development without sudden nutrient swings.
Soluble potash (K2O) is important because it helps plants control water use, move sugars to new growth and fruit, and build stronger, higher-quality structure under stress. It’s unique from many other nutrients because it acts more like a regulator and transport helper than a direct “building material,” so the biggest benefits show up as steadier growth, stronger stems, and better finishing instead of just bigger leaves.
Total Nitrogen is important because it directly drives leafy growth, chlorophyll production, and overall growth speed, which sets the pace for the entire plant. It’s unique because the “total” number can include different nitrogen forms that behave differently in the root zone, meaning the same total amount can produce very different results depending on the nitrogen type and plant stage.
Water soluble magnesium is important because it quickly restores the plant’s ability to make chlorophyll and produce energy, which helps stop interveinal yellowing on older leaves and improves overall nutrient use; it’s unique because it becomes available immediately in water, making it faster and more predictable than slower magnesium sources.
Iron EDTA keeps iron dissolved and available long enough for roots to absorb it, which is why it can quickly improve new growth color when iron is tied up in the root zone. It’s unique because the EDTA chelate balances stability and accessibility, making iron more reliably usable in mildly acidic to near-neutral conditions compared to many non-chelated iron forms.
Magnesium sulfate supplies magnesium for chlorophyll and sugar movement plus sulfur for protein building, helping plants stay efficient and green during high-demand growth. It’s unique because it adds magnesium without extra nitrogen or calcium, so it corrects magnesium issues with fewer side effects when balance is the real goal.
Manganese EDTA is unique because the EDTA chelate keeps manganese stable and more available during delivery, helping plants absorb it more reliably when manganese would otherwise lock up. This matters because manganese drives key enzyme functions tied to photosynthesis and healthy new growth, so consistent availability can prevent pale, chlorotic young leaves and stalled vigor.
Monoammonium phosphate feeds roots with phosphate for energy transfer and ammonium nitrogen for fast tissue building, which is why it can boost early rooting and growth more quickly than many other phosphorus sources. It’s unique because the ammonium portion can change root-zone pH and nutrient availability, so using it correctly supports roots, but overusing it can trigger imbalances that look like other deficiencies.
Monopotassium phosphate provides fast phosphorus and potassium that support energy use, nutrient flow, and bloom development without adding nitrogen, so it helps flowering progress cleanly without pushing extra leafy growth. It’s unique because it delivers a focused PK boost in a highly soluble form, which can correct stage-related demand quickly, but it must be used carefully to avoid potassium-heavy imbalances that can block calcium and magnesium uptake.
Potassium nitrate is often better for quick correction when the plant needs both potassium and fast nitrate nitrogen, because it dissolves cleanly and is taken up quickly, unlike potassium sources that don’t supply nitrogen. It’s unique because it can restore leaf color and growth momentum while also improving water regulation, but it can backfire if nitrogen is already high or if salt levels are already stressing the roots.
Zinc EDTA is important because it keeps zinc available in the root zone when pH or water chemistry would normally tie zinc up, helping new growth develop normally before deficiency symptoms get worse. It’s unique from other zinc forms because the EDTA chelate shields zinc in solution, making delivery more consistent when conditions are not ideal.

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