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Professional Greenhouse Water Soluble Fertilizers


Proven Winners® Professional Greenhouse Water Soluble Fertilizers are designed to improve pH management and minimize problems due to high pH levels.

Proven Winners® has developed eight specific formulations to minimize and correct pH related problems at different water alkalinity ranges, as well as cold weather growing and greening formulas. Each formula contains 100% FeEDDHA, the best chelated Iron form available, for improved plant Iron uptake at high pH levels and to correct Iron deficiency.

Order a Water Test Kit Online    PDF Icon View PDF    PDF Icon Formula Chart    PDF IconNutrient Concentration Chart

Formulated for Proven Winners® and Proven Selections® Plants to Match Your Specific Water Supply

One of the most frequently asked questions of Proven Winners® from growers across North America is how to best manage plant nutrition and pH. Based on the questions we receive, we know that incorrect fertilization and improper pH levels commonly result in grower production issues.

Because of this, we have developed Proven Winners® Professional Greenhouse Water Soluble Fertilizers:

  • These products are developed to work at different water alkalinity ranges in order to help minimize pH-related problems.
  • Based on review of a recent water test from your greenhouse or nursery, Proven Winners® will recommend one of four formulations targeted at specific water alkalinity ranges to help minimize pH-related problems.
  • There are also products for cold weather growing, as well as a greening formula.
  • The Iron source in each product is 100% FeEDDHA, the best chelated Iron form for plant uptake at higher pH levels.

The specific formulations of Proven Winners® Professional Greenhouse Fertilizers were developed by our own growers to address issues under various growing conditions. Plus, they are backed by the advice and service of the Proven Winners® propagator companies.

We'll Use Your Water Test Results to Help Select the Right Product for You

Which Proven Winners® Professional Greenhouse fertilizer is best for you to use is based on water test results. If you have a completed water test that is three months old or less, send the results to your Proven Winners® propagator. If you don't have a test kit, call your Proven Winners® propagator and they will send one to you. Once complete, send the results to your Proven Winners® propagator. When they receive your test results, they will then recommend the proper products based on your specific water test results.

Proven Winners® Professional Greenhouse Water Soluble Fertilizer Products

The eight fertilizer products available from Proven Winners® can be used with every irrigation. The specific product that you will use is based on your specific water conditions or needs:

  • 14-3-14 + Minors Low Alkalinity Formula with FeEDDHA
  • 16-4-16 + Minors Moderate Alkalinity Formula with FeEDDHA
  • 18-5-18 + Minors Moderately High Alkalinity Formula with FeEDDHA
  • 17-4-17 + Minors High Alkalinity Formula with FeEDDHA
  • 12-3-12 + Minors Cold Weather Formula with FeEDDHA. Contains high levels of Nitrate Nitrogen for cold weather conditions.
  • 16-4-8 + Minors Greening/pH Reducing Formula with FeEDDHA. A valuable tool to correct increases in pH and quickly green up a crop.
  • 0-9-6 + Minors Plant Holding Formula with FeEDDHA. Used to help "hold" plants that are at shipping size. Will also keep plants green and looking good.
  • Micronutrient Formula

Each Product Contains 100% EDDHA as its Source of Iron

All products listed above are made with 100% FeEDDHA. These products have a reddish-brownish color appearance due to the inclusion of the Iron EDDHA ingredient. 

According to Paul Pilon*, there's a phenomenon that occurs when crops (like annual geraniums & petunias) seemingly are grown at adequate soil pH and then they experience a sudden pH decline (SPD). It's not uncommon for the pH to suddenly drop one to two points. When this occurs, these plants often experience micronutrient toxicities from excessive availability of iron and manganese at low pH. These plants are also commonly referred to as iron-efficient plants.

Iron-efficient plants naturally have a great ability to take up iron and manganese. At normal pH ranges above 6.0, these plants normally grow and appear healthy. When the pH falls below 5.8, iron and manganese become more soluble, which makes them more available to the plant. When low pH is present, iron-efficient plants often take up too much of these micronutrients and toxicity or plant injury often occurs.

So you may be wondering, how do these plants lower the pH? Certain iron-efficient plants release acid ions when they take up ammonium or when they're deficient of phosphorus. The plants generally consume the phosphorus that's available, particularly during warm, bright days. This process causes the release of additional acid into the growing mix, which lowers the pH in the soil and causes any soil-bound phosphorus to become soluble or available to the plants. Unfortunately, this process of lowering the pH often leads to the increased availability of iron and manganese and often iron-manganese toxicity.

* Used with permission from the Perennial Pulse e-newsletter: July 27, 2018.



Proven Winners® Professional Greenhouse Water Soluble Fertilizers are packaged in 25 lb. bags. Bags are 5 mil. plastic bags, with a 2 mil. poly inner liner. Package labels are distinctly color coded for easy identification.

How to Order Proven Winners® Professional Greenhouse Water Soluble Fertilizers

Contact your Proven Winners® propagator:

Pleasant View Gardens, Inc.
Loudon, NH


Four Star Greenhouse, Inc.
Carleton, MI


These products are not available in Canada at this time.

  • At the time of your initial order, a recent water test taken within the last three months is required. We will review your water test and match your water alkalinity to the correct fertilizer products for your specific growing situation. If you do not have a recent water test, we will provide you with a test kit from our commercial lab or you can order a water test kit online.
  • After your initial order, you can reorder through your propagator or online. An updated water test is required.
  • Minimum order is one 25 lb. bag.
  • Pricing and freight quotes are provided by your Proven Winners® propagator. Orders can be made up of multiple or different products to reach freight quantity discounts.
  • Products are produced by Greencare Fertilizer and shipped to you by either Greencare or your Proven Winners® propagator. Final pricing is dependent on quantity ordered.
Water quality and fertilizer are only two of many factors that affect soil pH. Proven Winners® does not guarantee that these fertilizers will eliminate all of your pH and nutritional problems. Proven Winners® further recommends regular soil, tissue, and water testing to minimize pH and other nutritional problems. Additionally, these products are formulated for use with Proven Winners® and Proven Selections® annual and perennial plants. Use caution when applying on other plant material.

Products Produced by Greencare Fertilizer

Greencare Fertilizer is an innovator in water soluble fertilizer products and is focused on providing complete solutions to growers. Greencare takes the time and effort to manufacture these products in a controlled environment so they are completely uniform, bag-to-bag, and within the bag.


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