Humboldts Secret Supplies: Tools for Growing, Living & Thriving
Your Secret to Stronger, Healthier Plants..
Over one hundred thousand gardeners are in on it — see why beginners and experts trust us with their plants. From indoor pots to backyard beds, and everything in between.
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Plant nutrients and pest control that take the guesswork out of growing.
Humboldts Secret makes feeding and protecting plants simple, effective, and — dare we say — a little magical.
Increase yields by 568%.
No myths, just Humboldts Secret. See the proof on screen — in real-world tests, our plant nutrient system boosted yields by over 500%. Imagine what it could do for your garden.
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Stronger yields . Faster growth . Healthier plants .
Grow more with less
Up to 568% more yield compared to untreated soil.
See results in just days
Growth you can measure within a week — fuller leaves, stronger stalks, and plants that are alive and thriving..
No more trial and error
Our system skips the guesswork and delivers consistent results, even for beginners.
Not sure where to start?
Every gardener’s initiation is different — here’s the simplest way in. Our Starter Kit gives you the tools to feed your plants exactly what they need, with less waste, less confusion, and more visible results.
- Comes with everything you need for a full growth cycle.
- Simple, beginner-friendly instructions (no pH math required).
- Works for indoor plants, patio pots, raised beds, small greenhouses, and backyard gardens.
“My plants turned around in a week. I’ve never had this kind of success with other products.”
Pick your product. Unlock your results.
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Starter Kit
From $59.97
World's Best Indoor & Outdoor Plant Fertilizer and Nutrient System
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Starter Kit
Mini - 6 Bottle Set (48 Ounce)
Starter Kit 2 – 8 Bottle Set (216 Ounce Total)
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Starter Kit 2 – 8 Bottle Set (216 Ounce Total)
From $169.97
Starter Kit 2 – 8 Bottle Set (216 Ounce Total) 94 reviews (94)
World's Best Indoor & Outdoor Plant Fertilizer and Nutrient System
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Starter Kit 2 – 8 Bottle Set (216 Ounce Total)
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Golden Tree
From $29.97
Golden Tree 1,474 reviews (1,474)
Our Signature All-In-One Additive
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Golden Tree
8 Ounce
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Base A & B Bundle
From $19.97
Base A & B Bundle 404 reviews (404)
World's Best Base Nutrient System
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Base A & B Bundle
8 Ounce - Bundle
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Flower Stacker
From $16.97
Flower Stacker 329 reviews (329)
Flowering Booster to Increase Yields
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Flower Stacker
8 Ounce
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Plant Enzymes
From $30.97
Plant Enzymes 137 reviews (137)
Highly Concentrated Enzymatic Formula
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Plant Enzymes
8 Ounce
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Sweet & Sticky
From $18.97
Sweet & Sticky 276 reviews (276)
Carbohydrate and Energy Source for Microbial Life
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Sweet & Sticky
8 Ounce
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CalMag & Iron
From $13.97
CalMag & Iron 241 reviews (241)
CalMag & Iron to Correct Common Deficiencies
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CalMag & Iron
8 Ounce
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Tree Trunk
From $15.97
Product for Plant Strength and Stress Resistance
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Tree Trunk
8 Ounce
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Flower Shield
From $29.97
Flower Shield 144 reviews (144)
Natural Insecticide, Fungicide and Miticide
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Flower Shield
8 Ounce
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PH Up
From $13.97
Liquid PH Up Buffering For PH Stability
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PH Up
8 Ounce
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PH Down
From $12.97
Liquid PH Down Buffering For PH Stability
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PH Down
8 Ounce
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Everything Growing
From $29.97
Everything Growing 133 reviews (133)
All Purpose Plant Food and Fertilizer Powder 20-20-20
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Everything Growing
2 Pound
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Everything Outdoor
From $25.97
Everything Outdoor 128 reviews (128)
All Purpose Lawn, Plant, Vegetable, Fruit & Tree Food 5-5-5
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Everything Outdoor
32 Ounce - Spray
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4-1 Soil Meter
From $18.97
Easily monitor pH levels, temperature, humidity, and brightness both indoors and outdoors with our versatile 4-in-1 soil meter.
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4-1 Soil Meter
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Fabric Grow Bags
From $15.99
Fabric Grow Bags 42 reviews (42)
Premium Non-Woven Fabric Grow Bags
Pro-grade results for anyone with a house and a hose.
You don’t need a greenhouse or an oracle to grow something great. Humboldts Secret makes it easy to feed your plants the nutrients they actually need. No second-guessing, no nutrient burn.
- Clear instructions and easy measuring.
- Safe for all plant types, from houseplants to herbs.
- Works in pots, raised beds, balconies, and beyond.
We’re so confident you’ll see stronger, healthier plants that every bottle is backed by our 6‑Month, 100% Satisfaction Guarantee.
Real gardeners. Real results.
Using these so far has been great. I’m really happy with the results and how well everything is working.
K
Krysta
Verified purchase
Ive been using this product line for few years now and i have to say...... It is a must for a wide variety of household and outdoor plants. All my plants are thriving
H
Harold
Verified purchase
Really like this product a lot but still trying to figure out why it says you don't have to flush.... I decided just to flush it anyway and the results have been fantastic!!!
M
Micheal
Verified purchase
Nothing beats the results from Humboldt. Foolproof instructions make it great even for beginners.
A
Alishia
Verified purchase
Humboldt is the best stuff we’ve ever used!! Amazing results!! Best prices, and super fast shipping
K
Karo
Verified purchase
This product exceeded my expectations. My plants grew fast, stayed healthy, and produced amazing results. I’ve recommended it to all my friends.
C
Conor
Verified purchase
Very pleased with this product. After switching to Humboldt’s Secret, my plants have had zero deficiencies. One of the best on the market!
T
Terrilynn
Verified purchase
No issues. Perfect the whole way form seed to harvest
K
Kevin
Verified purchase
Meet the gardener who uncovered the Secret.
Before Humboldts Secret Supplies became a trusted name in plant nutrients, Yousef was just trying to solve a problem with his own plants: why were so many products failing to deliver the results they promised?
He started experimenting, testing different blends, and tracking what actually made plants thrive, and what didn’t. After countless refinements, he unlocked natural pest control and liquid plant food formulas that worked — a Secret worth sharing. Friends asked for them. Then customers. Now, over one hundred thousand gardeners use Humboldts Secret.
And Yousef? He still leads the company today with the same philosophy it began with: give people the tools to grow well, without overcomplicating the process or cutting corners on quality.
Excellent customer service
Free shipping for orders over $89
6-Month Satisfaction Guarantee
Secrets worth sharing: Tips, how-tos, and growing smarter
Winter Feeding Mistakes That Stall Early Growth and How to Avoid Them
#### Winter Feeding Mistakes That Stall Early Growth and How to Avoid Them
Cold roots and slower winter uptake can make feeding mistakes costly. Learn how to adjust winter nutrients for healthy early growth.
How to Reset Your Root Zone After Holiday Feeding Without Stressing Your Plants
#### How to Reset Your Root Zone After Holiday Feeding Without Stressing Your Plants
Holiday feeding can leave salt buildup in the root zone. Learn how to safely reset your root zone in winter without stressing plants.
Slow Growth Does Not Mean Hungry Plants: How to Read Winter Signals Correctly
#### Slow Growth Does Not Mean Hungry Plants: How to Read Winter Signals Correctly
Slow growth in winter does not always mean plants need more nutrients. Learn how to read winter signals and avoid overfeeding mistakes.
Cold Roots, Warm Rooms: How Winter Root Zones Sabotage Indoor Gardens
#### Cold Roots, Warm Rooms: How Winter Root Zones Sabotage Indoor Gardens
Cold air below the soil can slow growth, block nutrients, and stress roots. Learn how cold root zones affect winter gardens and how to fix it.
Why Feeding More in January Backfires and How to Feed Smarter in Winter
#### Why Feeding More in January Backfires and How to Feed Smarter in Winter
Feeding more in January often harms plants. Learn why winter nutrients behave differently and how to feed smarter without stressing roots.
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Starter Kit
From $59.97
Starter Kit 2 – 8 Bottle Set (216 Ounce Total)
From $169.97
Base A & B Bundle
From $19.97
Golden Tree
From $29.97
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