Get the Right Fertilizer for Your Plants in Under 2 Minutes
Stop guessing what your tomatoes, citrus, or hydroponic system actually needs. Answer a few questions about your crop and growing conditions — we’ll match you to the exact formula our team recommends, backed by 35+ years of California formulation experience.
- Made in California Since 1989
- CDFA Registered
- FDA-Registered Facility
- 1,580+ Verified Reviews
Why This Quiz Works
Real Expertise
Built on 35+ years of formulating fertilizers in California for commercial growers, hobbyists, and hydroponic farms. We know which inputs actually work for which problems — because we’ve watched them work in the field.
Verified Quality
CDFA-registered, manufactured in an FDA-registered facility, and heavy-metal tested for lead, cadmium, arsenic, and mercury on selected products. Every recommendation comes from formulas built to meet California’s strict agricultural standards.
Custom-Blended Formulas
Most of our recommendations are formulas we developed ourselves — not relabeled commodity products. NPK ratios are dialed in for the specific crop or problem, not generic catch-alls that try to do everything and nothing well.
Find Your Match in Under 2 Minutes
Answer a few questions about your crop, soil, and goals — we’ll match you to the right fertilizer with application rates and timing included.
Growers Who Found Their Match
Real results from verified buyers — not curated marketing copy. These are the outcomes that keep customers coming back.
Once You Have Your Match
Getting the right fertilizer is half the job. Applying it correctly is the other half. Here’s what to know once your recommendation is in hand.
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Read the NPK numbers
The three numbers on every fertilizer bag — like 4-18-38 — tell you the percentage of nitrogen, phosphate, and potash by weight. A higher first number drives leaf and stem growth; higher middle and last numbers support flowering, fruiting, and root development.
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Match application timing to crop stage
Pre-plant, vegetative growth, flowering, and fruiting all need different ratios. The quiz factors crop stage into its recommendation, but every product page also includes a stage-by-stage feeding schedule you can follow.
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Water-soluble vs. granular
Water-soluble formulas dissolve fully and act fast — ideal for hydroponics, foliar feeding, and quick deficiency correction. Granular and organic meals release nutrients slowly over weeks to months and feed soil biology while they work.
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Don’t guess on rates
Every product page lists exact mixing rates, application frequency, and total seasonal amounts per square foot or per gallon. Following the listed rates prevents fertilizer burn, salt buildup, and the kind of over-application that does more damage than it fixes.
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Soil tests are worth doing
If you’re seeing repeated problems despite fertilizing correctly, get a soil test before doubling your inputs. A $25 lab test reveals pH, base nutrient levels, and what your soil actually has to offer — information no quiz or guess can give you.
Need Something More Specific?
If you already know you need a nitrogen source or you only want OMRI-listed organic options, jump to the focused quiz that matches your situation.
Nitrogen Fertilizer Quiz
Compare urea, ammonium sulfate, calcium nitrate, blood meal, feather meal, and more nitrogen sources matched to your exact use case — soil pH, crop type, application method, and release speed.
Organic Fertilizer Quiz
Match the right organic amendment to your crop and soil — blood meal, feather meal, bone meal, fish bone meal, kelp, alfalfa, cottonseed meal, and Azomite. Built around OMRI-listed and naturally derived inputs.
Frequently Asked Questions
How accurate is the quiz?
The quiz uses scoring logic built around 35+ years of formulation experience and the same matching criteria our team uses when growers call us for advice. It accounts for crop type, growth stage, soil conditions, and application method to narrow down the right product. It is not a substitute for a soil test, but for most home growers and small operations it gives a reliable starting point.
What if my plant problem isn’t in the quiz?
The quiz covers the most common crops, deficiencies, and growing scenarios. If your situation is unusual — uncommon ornamentals, large-scale agricultural operations, or persistent issues that fertilizer alone won’t fix — email us at questions@greenwaybiotech.com or call (562) 351-5168 Monday through Friday, 7 AM to 5 PM PST. A real person will help you work through it.
Are Greenway fertilizers organic?
Some are and some are not. Our organic line includes blood meal, feather meal, bone meal, fish bone meal, kelp meal, alfalfa meal, cottonseed meal, and Azomite — many of these are OMRI-listed for use in certified organic production. Our water-soluble crop blends and single-nutrient products are conventional. Check individual product pages for OMRI listing status and certifications.
Where are Greenway products made?
Every Greenway fertilizer is custom-blended at our family-owned facility in Madera, California, in the Sierra Nevada foothills. We’ve been operating in California since 1989. Our manufacturing facility is FDA-registered, and our fertilizers are registered with the California Department of Food and Agriculture (CDFA).
How fast will I see results?
It depends on the product and the issue. Water-soluble fertilizers applied as a soil drench or foliar spray can show visible response in 3 to 7 days for nutrient deficiencies. Granular and organic meal products release more slowly and typically show their full effect over 4 to 8 weeks as soil microbes break them down. Long-term soil-building from organics builds over multiple seasons.
Do you ship internationally?
We ship throughout the United States and to select international destinations. International shipping availability and rates vary by product weight and destination country. Add items to your cart and enter your address at checkout to see exact shipping options for your location.
What’s your return policy?
Unopened products in original packaging may be returned within 30 days of delivery for a refund of the product price. Shipping costs are non-refundable, and return shipping is the customer’s responsibility unless the return is due to a product defect or shipping error on our end. Email questions@greenwaybiotech.com to start a return.
Can I use these fertilizers in hydroponics?
Yes — many of our water-soluble products are formulated specifically for hydroponic use, including our crop-specific blends, Cal-Mag Plus 2-0-0, calcium nitrate, monopotassium phosphate (MKP), and our chelated micronutrients. Each hydroponic-suitable product page includes mixing rates in PPM and EC ranges. Note that calcium and phosphate must never be combined in the same concentrated stock tank — always mix them in separate A/B reservoirs.
How is Greenway different from brands sold on Amazon?
We sell directly on Amazon as well — Greenway is the manufacturer, not a reseller. The difference between us and most fertilizer brands you’ll find online is that we formulate and blend our own products at our California facility instead of relabeling commodity inputs. Our crop-specific NPK ratios are dialed in for the actual nutritional needs of each crop, and we’ve been doing it for 35+ years.
Are your fertilizers safe for pets and children?
Fertilizers are not food and should be stored out of reach of children and pets. Once applied and watered into the soil according to label directions, the area is generally safe for normal use. Granular organic meals like blood meal and bone meal can attract dogs by smell — work them into the soil rather than leaving them on the surface, and keep pets away from freshly applied areas until everything is watered in. Always follow the safety instructions on the product label.
Stop Guessing. Get Your Match in Under 2 Minutes.
Personalized fertilizer recommendations backed by 35+ years of California formulation experience — with application rates and timing included.
Find My Fertilizer