Fertilizers
Fertilizers for every crop, soil type, and growing method
Greenway Biotech has manufactured and sourced high-quality fertilizers from Madera, California since 1989. Our catalog covers the full spectrum of plant nutrition — from fast-acting water-soluble formulas for hydroponics and foliar feeding, to slow-release organic amendments that build long-term soil health, to precision chelated micronutrients for pH-challenging soils. Products in this collection are CDFA registered, third-party tested for heavy metals, and backed by our 90-day guarantee.
Whether you're looking for the best fertilizer for your vegetable garden, a fast-acting plant fertilizer to correct a mid-season deficiency, or a complete hydroponic nutrient system, Greenway Biotech's catalog has a solution for every growing situation. Use the sub-collections below to navigate directly to the category that fits your needs — or browse all 45+ products in the grid.
También ofrecemos fertilizantes orgánicos, quelatos, y nutrientes para hidroponía — fabricados en California desde 1989.
Shop by category
Not sure where to start? Each sub-collection is focused on a specific nutrient, growing method, or product type — with its own buying guide and product comparison table.
How to choose the right fertilizer
The right garden fertilizer depends on three things: what nutrient your plants need, how quickly they need it, and how you plan to apply it. Here's a quick framework:
Grow method: soil or raised beds
Water-soluble fertilizers work for regular feeding. Organic amendments build long-term fertility. Combine both for best results — organics as the foundation, water-solubles for peak demand.
Grow method: hydroponics or soilless
Use the hydroponic nutrient system (Cal-Mag Plus + Grow Green + Blossom Green + Micro Green). Chelated micronutrients keep trace elements stable in solution.
Soil pH above 6.5 — nutrients locking up
Chelated micronutrients (Iron EDTA, Iron DTPA, Zinc, Manganese, Copper) stay plant-available in alkaline conditions where sulfate forms precipitate out.
Growing a specific crop
Specialty fertilizers (Tomato 4-18-38, Lettuce 8-15-36, Pepper 11-11-40, Cucumber 8-16-36, Strawberry 8-12-32) are pre-formulated for crop-specific NPK ratios with chelated micronutrients.
Organic vs. synthetic vs. chelated — what's the difference?
| Type | How it works | Release speed | Best for | Examples |
|---|---|---|---|---|
| Organic | Nutrients released as soil microbes break down natural materials | Slow (weeks to months) | Soil building, long-season feeding, certified organic programs | Blood Meal, Bone Meal, Kelp Meal, Alfalfa Meal, Azomite |
| Water-soluble synthetic | Nutrients dissolve completely in water and are immediately available for root uptake — no waiting for microbial breakdown | Fast (days) | Correcting deficiencies quickly, hydroponics, fertigation, foliar feeding | Urea 46-0-0, Calcium Nitrate, MAP 12-61-0, Potassium Sulfate 0-0-53 |
| Chelated micronutrients | Metal ions bound to organic ligands that prevent precipitation in high-pH soil | Fast (available on contact) | Iron, zinc, manganese, copper deficiency in alkaline or neutral soils | Chelated Iron EDTA, Iron DTPA, Zinc EDTA, Manganese EDTA |
| Specialty crop formulas | Pre-blended NPK ratios matched to specific crop requirements at key growth stages | Fast (water-soluble) | Home growers who want one product optimized for their specific crop | Tomato 4-18-38, Lettuce 8-15-36, Pepper 11-11-40, Strawberry 8-12-32 |
For deeper guidance on choosing and applying fertilizers:
Read: Sulfate vs. Chelated Fertilizers — Key Differences Explained →
Read: Best Fertilizers for a Vegetable Garden →
Read: The Organic Gardener's Guide to Soil Preparation →
Frequently asked questions
What does NPK mean and how do I read a fertilizer label?
NPK stands for nitrogen (N), phosphorus (P), and potassium (K) — the three primary macronutrients plants need in the largest quantities. The three numbers on every fertilizer bag (e.g., 10-10-10 or 46-0-0) are the guaranteed analysis: the percentage by weight of available N, P₂O₅ (phosphate), and K₂O (potash) in that order. A bag labeled 21-0-0 contains 21% nitrogen and no phosphorus or potassium. A 4-18-38 label means 4% nitrogen, 18% phosphate, and 38% potash. Note that P and K values are expressed as P₂O₅ and K₂O rather than elemental phosphorus and potassium — this matches how soil fertility is reported on fertilizer labels industry-wide. Secondary nutrients (calcium, magnesium, sulfur) and micronutrients (iron, zinc, manganese, copper, boron, molybdenum) are listed separately when present in guaranteed amounts.
Can I use water-soluble fertilizers in organic gardens?
Not all water-soluble fertilizers are approved for certified organic production — most synthetic water-solubles (Urea, Calcium Nitrate, MAP, MKP, Potassium Sulfate) are not OMRI listed and are not permitted in certified organic programs. However, some water-soluble products derived from organic sources may qualify. If organic certification matters for your operation, check individual product pages for OMRI status and consult your certifying agency. For home gardens without certification requirements, synthetic water-solubles are widely used alongside organic amendments.
What's the difference between soil application and foliar feeding?
Soil application delivers nutrients to the root zone — either as a dry broadcast/incorporation or dissolved in irrigation water (fertigation). Nutrients are taken up through the root system over time. Foliar feeding involves spraying a dilute fertilizer solution directly onto leaves for rapid absorption through the leaf surface — useful for correcting acute deficiencies quickly or supplementing during high-demand growth stages. Foliar feeding is not a substitute for healthy soil nutrition; it's most effective as a targeted supplement. Only water-soluble fertilizers should be used for foliar applications. Apply in the early morning or evening when temperatures are below 85°F and foliage is dry — never during heat stress or midday sun.
How do I know if my plants have a nutrient deficiency?
Most nutrient deficiencies produce visible symptoms on leaves — the pattern tells you which nutrient is involved. Yellowing that starts on older, lower leaves typically indicates nitrogen or magnesium deficiency (mobile nutrients). Yellowing between leaf veins on young, new leaves (interveinal chlorosis) is the classic sign of iron, zinc, or manganese deficiency (immobile micronutrients). Stunted new growth with short internodes suggests zinc deficiency. Purple or reddish leaf undersides can indicate phosphorus deficiency, especially in cold soils. A soil test is the most reliable way to confirm which nutrients are genuinely deficient before purchasing amendments.
Are Greenway Biotech fertilizers safe for edible crops?
Yes. Products in this collection are CDFA registered and manufactured under quality-controlled conditions at our Madera, California facility. Organic products are derived from natural plant, animal, or mineral sources. Synthetic fertilizers are manufactured to food and agricultural grade standards. All products are third-party tested for heavy metals — results are available on our Heavy Metal Analysis page. Follow recommended application rates on individual product pages. For edible crops, avoid applying any fertilizer directly to foliage within 2 weeks of harvest.
Do you offer free shipping?
Yes — free shipping on all orders over $100 to the continental United States. All products are shipped from our Madera, California facility. For questions about your order, contact us at questions@greenwaybiotech.com or call (562) 351-5168, Monday–Friday 7AM–5PM PST.