The Multiplier. Your shortcut to legendary blooms.
A concentrated flower booster that turns mid-flower into a stacking frenzy — across soil, coco, or hydroponic systems. No burn. No messy mixing. Just fuller, denser blooms.
Enhances yield and flower density mid-bloom
High in Phosphorus, Potassium & B1
Noticeable results within days
“The best harvest in years.” “Humongous, beautiful flowers.”
$17.97
Get bigger, better blooms with less effort.
Designed for gardeners who want better flower performance, without changing their entire system. Flower Stacker delivers a reliable mid-phase boost — fast, clean, and safe for any flowering or fruiting plant.
“Even my late-season plants stacked beautifully. Best harvest in years.”
Versatile use: Soil, coco, hydroponic systems, & towers — it fits your grow
Compatible: Works with every other nutrient system you run.
Trusted by gardeners: 5-star favorite with repeat buyers
Fast results: See changes within 3–10 days
Plant-safe formula: No banned PGRs, no harsh chemicals
Mid-Bloom booster: Amplifies density and size during flowering
Versatile use: Soil, coco, hydroponic systems, & towers — it fits your grow
Compatible: Works with every other nutrient system you run.
Trusted by gardeners: 5-star favorite with repeat buyers
Fast results: See changes within 3–10 days
Plant-safe formula: No banned PGRs, no harsh chemicals
Mid-Bloom booster: Amplifies density and size during flowering
Every dose of Flower Stacker includes a clean, targeted blend of high Phosphorus, Potassium, and Vitamin B1 — the trifecta behind denser flowers, faster stacking, and stronger plant performance.
Zero harmful growth regulators (PGRs)
Clean inputs only
Safe for edibles, ornamentals, and everything in between
Choose your bloom phase: Start mid-flower (weeks 2-3)
2
Dilute carefully: 1ml per gallon
3
Feed weekly: Add to your regular watering ritual
4
Stop 1-2 weeks before harvest
5
Watch your blooms build
Gardener’s Tip: Handle with respect, even a small dose makes it simpler than ever to transforms harvests.
Compatible in any nutrient setup.
Unlock the full glory of your blooms.
If your plants are in flower but still look sparse, they need more than base nutrients. Don’t let poor bloom development cost you your grow. Flower Stacker gives them what they’re missing — creating a yield worth bragging about.
“I almost skipped this additive. Now I won’t grow without it.”
Yes, you can use Flower Stacker on your apple tree — and other answers.
What plants can I use Flower Stacker on?
Flower Stacker works on any flowering or fruiting plant, including vegetables, ornamentals, flowering houseplants, fruit trees, and vines. It’s especially useful during bloom phases when plants are building buds, petals, or fruit.
Does it contain any harmful PGRs?
No — Flower Stacker is completely free from harmful or banned Plant Growth Regulators (PGRs). It’s formulated with clean, plant-safe ingredients that support natural growth.
What’s in Flower Stacker?
Each bottle contains Phosphate, Soluble Potash (Potassium), and Vitamin B1 - a powerful trio for stimulating bloom development, root health, and flower production.
Flower Stacker is designed to work within any feeding system, including the full Humboldts Secret line. Just start low and adjust based on your plant's response. 1 mL raises PPMs by ~20 — small amounts make a big impact.
How much should I use per gallon of water?
Start with 1 mL per gallon of water. This formula is highly concentrated, so only increase as you see your plants respond well. Always dilute before use and avoid mixing concentrates directly together.
How often should I apply Flower Stacker?
Apply once per week during the flowering stage. Stop feeding 1–2 weeks before your final flush or harvest to allow plants to finish naturally.
Is this product safe for edible plants like tomatoes or herbs?
Flower Stacker is safe to use on edible crops. Just follow label directions and observe appropriate intervals between final feeding and harvest for best flavor and safety.
Can I use Flower Stacker in soil, coco, or hydroponic systems?
Flower Stacker works well in all major growing mediums, including traditional potting soil, coco coir, and hydroponic systems. Our customers have also seen strong results with aeroponic and tower garden setups.
How soon will I see results?
Many of our gardeners tell us they can see visible improvements in flower size and plant vitality within 3–10 days from the first time they use Flower Stacker. Expect tighter blooms, more vibrant color, and better stacking over time.
Why do I need Flower Stacker if I’m already using a base nutrient?
Base nutrients provide general support, but Flower Stacker focuses specifically on the bloom phase. Its phosphorus and potassium boost helps flowers develop more fully and produce higher yields, especially important during mid to late flowering.
How long will a bottle last?
Thanks to its concentration, even the 8 oz size stretches far, often across multiple cycles. For example, at 1 mL per gallon, a single 32 oz bottle can treat over 900 gallons of water.
Your trusted bloom ritual.
Over one hundred thousand gardeners trust Humboldts Secret Supplies to deliver real results. Whether you're coaxing treasured fruit trees, nurturing a blooming garden, or growing your own salad, Flower Stacker helps your plants meet their potential.
Try it risk-free with our 6-Month Satisfaction Guarantee.
