--- product_id: 659850844 title: "Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce" brand: "humboldts secret" price: "€ 26.67" currency: EUR in_stock: true reviews_count: 9 category: "Humboldts Secret" url: https://www.desertcart.sk/products/659850844-humboldts-secret-ph-down-for-plants-liquid-ph-adjuster-balancer store_origin: SK region: Slovakia --- # 25% stronger concentration Optimal pH 5.5-6.5 balance Versatile liquid formula Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce **Brand:** humboldts secret **Price:** € 26.67 **Availability:** βœ… In Stock ## Summary > 🌿 Unlock your garden’s full potential with precision pH mastery! ## Quick Answers - **What is this?** Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce by humboldts secret - **How much does it cost?** € 26.67 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.sk](https://www.desertcart.sk/products/659850844-humboldts-secret-ph-down-for-plants-liquid-ph-adjuster-balancer) ## Best For - humboldts secret enthusiasts ## Why This Product - Trusted humboldts secret brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Precision pH Control:** Quickly lowers pH to ideal 5.5-6.5 range for maximum nutrient uptake. - β€’ **Boosts Plant Vitality:** Prevents nutrient lockout, supports strong roots, lush foliage, and abundant harvests. - β€’ **Universal Compatibility:** Perfect for soil, coco, hydroponics (DWC, NFT), and all grow mediums. - β€’ **Pure & Professional Grade:** Made with high-grade phosphoric acid, no dyes or additives, trusted by expert growers. - β€’ **Ultra-Concentrated Formula:** Up to 25% stronger than competitors, requiring less product per use. ## Overview Humboldts Secret pH Down is a highly concentrated liquid phosphoric acid solution designed to rapidly and precisely lower pH levels in soil, coco, and hydroponic systems. Engineered for professional growers, it ensures optimal nutrient absorption by maintaining pH between 5.5 and 6.5, promoting healthier, more vigorous plant growth. Its versatile formula works across all growing mediums, delivering reliable, efficient results with minimal product use. ## Description Product description Product Comparisons pH Up & Down pH Down pH Up Base A & B Golden Tree Sweet & Sticky Review: Humboldt ph dn - Works great and I use less then other brands per feeding Review: This stuff is great! - The pH on my cannabis plants was at about 7 1/2 almost 8. They were not taking up nutrients like they should, which is obvious by their stunted growth and within one water and using pH down it… Problem solved! Perfect, 6.7 PH. All I did was mix my feeding solution take the pH, Then add pH down until the pH was at around 3 1/2 which I figured is half of the approximate 6 1/2 I was looking to get. And it got me there right on the line. The only problem with this product is there are no real directions. You kind of have to do trial by error and let me tell you folks please err on the side of caution. This is straight acid that will definitely burn your plants so do not apply this directly. Do not apply this in high doses. I would say start with a cap full in a gallon of your feeding solution and then go from there, adding more until you get to where you want to be. That said, I kind of understand why the directions are the way they are because every solution is a different pH, so there is no perfect amount. It’s always going to be based on your water quality and the pH of your nutrient base. At any rate, I will tell you that this product works absolutely great. I would avoid getting it on the plant itself and apply only to the soil. Happy growing.βœŒοΈπŸ™β€οΈπŸ€©πŸŒ±πŸŒ³ ## Features - Packaging Update: You may receive previous or updated packaging during our transition. Same formula, same performance. Balance Your Grow Medium Fast - Our Humboldts Secret pH Down quickly and effectively lower pH in soil or coco to the optimal range for nutrient absorption. Prevents deficiencies and keeps plants stress-free while creating the right foundation for strong roots lush foliage and abundant harvests. - Fuel Stronger Healthier Growth: Maintain precise plant pH balance between 5.5 and 6.5 to prevent nutrient lockout and maximize vitality. Works for vegetables flowers and herbs in any medium helping your garden thrive from seedling to full production with consistent vibrant growth. - Highly Concentrated and Efficient: Just a small amount of our hydroponic pH down makes powerful lasting adjustments saving you time and money. Up to 25% stronger than some competitors this commercial grade formula ensures reliable results with minimal product use. - Versatile for All Growing Methods: Use Humboldts Secret pH Down in soil hydroponic systems like DWC and NFT coco coir or other grow mediums. Works seamlessly with your nutrient solution to support balanced feeding healthy stems and increased yields year round. - Expert Made Quality You Can Trust: Designed by growers for growers our concentrated pH down for plants uses high grade phosphoric acid and contains no dyes or additives. Proudly manufactured in California it delivers professional level results for every type of garden. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B0DFN2JDB2 | | Best Sellers Rank | #33,515 in Patio, Lawn & Garden ( See Top 100 in Patio, Lawn & Garden ) #955 in Garden Fertilizers | | Brand | Humboldts Secret | | Brand Name | Humboldts Secret | | Coverage | Medium | | Customer Reviews | 4.6 out of 5 stars 453 Reviews | | Item Form | Liquid | | Item Weight | 0.63 Pounds | | Liquid Volume | 8 Fluid Ounces | | Manufacturer | Humboldts Secret | | Model Number | pHDown8oz | | Number of Items | 1 | | Target Species | plants, trees, flowers, bushes, lawns | | UPC | 850058984438 | | Unit Count | 8.0 Fluid Ounces | ## Product Details - **Brand:** Humboldts Secret - **Item Form:** Liquid - **Item Weight:** 0.63 Pounds - **Liquid Volume:** 8 Fluid Ounces - **Manufacturer:** Humboldts Secret ## Images ![Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce - Image 1](https://m.media-amazon.com/images/I/616qVWfyuwL.jpg) ![Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce - Image 2](https://m.media-amazon.com/images/I/71t1gWeLtpL.jpg) ![Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce - Image 3](https://m.media-amazon.com/images/I/8100ESQD1dL.jpg) ![Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce - Image 4](https://m.media-amazon.com/images/I/81cB+GV2ynL.jpg) ![Humboldts Secret pH Down for Plants | Liquid pH Adjuster and Balancer for Soil Coco Hydroponics | Concentrated Phosphoric Acid Solution Supporting Nutrient Uptake and Strong Growth | 8 Ounce - Image 5](https://m.media-amazon.com/images/I/91TFAK06jGL.jpg) ## Available Options This product comes in different **Size** options. ## Customer Reviews ### ⭐⭐⭐⭐⭐ Humboldt ph dn *by R***N on November 4, 2025* Works great and I use less then other brands per feeding ### ⭐⭐⭐⭐⭐ This stuff is great! *by R***H on June 15, 2023* The pH on my cannabis plants was at about 7 1/2 almost 8. They were not taking up nutrients like they should, which is obvious by their stunted growth and within one water and using pH down it… Problem solved! Perfect, 6.7 PH. All I did was mix my feeding solution take the pH, Then add pH down until the pH was at around 3 1/2 which I figured is half of the approximate 6 1/2 I was looking to get. And it got me there right on the line. The only problem with this product is there are no real directions. You kind of have to do trial by error and let me tell you folks please err on the side of caution. This is straight acid that will definitely burn your plants so do not apply this directly. Do not apply this in high doses. I would say start with a cap full in a gallon of your feeding solution and then go from there, adding more until you get to where you want to be. That said, I kind of understand why the directions are the way they are because every solution is a different pH, so there is no perfect amount. It’s always going to be based on your water quality and the pH of your nutrient base. At any rate, I will tell you that this product works absolutely great. I would avoid getting it on the plant itself and apply only to the soil. Happy growing.βœŒοΈπŸ™β€οΈπŸ€©πŸŒ±πŸŒ³ ### ⭐⭐⭐⭐⭐ Yep *by B***6 on April 30, 2026* As promised ## Frequently Bought Together - Humboldts Secret pH Down | Liquid pH Plant Balancer for Soil & Hydroponics Growing System (8 Ounce) - VIVOSUN Digital pH and TDS Meter Kits, 0.01pH High Accuracy Pen Type pH Meter Β± 2% Readout Accuracy 3-in-1 TDS EC Temperature Meter for Hydroponics, Pool and Aquarium, Yellow Blue, UL Certified - Humboldts Secret Set of A & B Liquid Hydroponics Fertilizer - World's Best Nutrient System – Hydroponic Nutrients for Outdoor, Indoor Plants – Supports Vegetative and Flowering Stages of Plants --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.sk/products/659850844-humboldts-secret-ph-down-for-plants-liquid-ph-adjuster-balancer](https://www.desertcart.sk/products/659850844-humboldts-secret-ph-down-for-plants-liquid-ph-adjuster-balancer) --- *Product available on Desertcart Slovakia* *Store origin: SK* *Last updated: 2026-05-29*