Converting granular fertilizer into a liquid feed offers faster nutrient absorption and simplified application via a sprayer. This allows plants, especially seedlings or those with deficiencies, to access nutrients immediately without waiting for granules to break down. Success depends entirely on the chemical makeup of the granular product chosen. The goal is to create a concentrated stock solution that must be diluted later for safe use.
Understanding Granular Composition and Solubility
The major factor determining convertibility is the fertilizer’s solubility in water, which relates directly to whether it is a quick-release or slow-release product. Quick-release fertilizers, such as urea, ammonium sulfate, or potassium nitrate, are the best candidates because they are comprised of highly water-soluble salts. These formulations dissolve rapidly upon contact with water, making nutrients instantly available to the plant.
Slow-release granules are largely unsuitable for quick liquid conversion due to their protective structure. These pellets often feature coatings, like sulfur or polymers, which control the rate of dissolution over weeks or months. Attempting to dissolve these coatings quickly is ineffective, and the undissolved material can cause significant problems. Furthermore, many standard granular fertilizers contain insoluble materials, such as clay, sand, or other inert fillers, included to aid in spreading. These non-nutrient carriers will not dissolve and must be filtered out.
Step-by-Step Guide to Mixing
The conversion process begins by selecting a water-soluble granular product and gathering the necessary materials, including a large bucket, warm water, a stirring implement, and safety gear. Start by pouring the measured granular fertilizer into the bucket before adding any liquid. A common starting ratio for creating a concentrate is approximately one cup of granular fertilizer for every gallon of water, though this may vary based on the NPK concentration.
Next, add warm water, ideally between 80°F and 90°F, as the higher temperature facilitates dissolution. Stir the mixture thoroughly to initiate the dissolving process and prevent clumping at the bottom of the container. Allow the solution to sit for a minimum of 24 hours to ensure all soluble particles have fully dissolved. Stirring the mixture periodically throughout this soaking period will help maximize nutrient extraction.
The final step is straining the resulting concentrate to remove any undissolved solids or fillers. Use a fine-mesh strainer, cheesecloth, or similar material to decant the liquid into a separate, clean container. Removing this sediment is crucial because insoluble particles can quickly clog the nozzles of sprayers and application equipment. The strained liquid is now a concentrated stock solution that should be labeled and stored in a cool, dark location away from direct sunlight.
Determining Concentration and Safe Application
Using the concentrate directly on plants is not recommended, as the high concentration of soluble salts can draw water out of plant tissues, causing chemical burn known as foliar scorch. The stock solution must be significantly diluted before application to prevent this damage and ensure effective nutrient uptake. Since commercial liquid fertilizers provide precise instructions, a homemade concentrate requires a cautious approach due to its unknown exact concentration.
A standard starting dilution for general-purpose use is mixing one to two tablespoons of the concentrate into one gallon of water. For sensitive plants, seedlings, or foliar feeding applications, start with the weakest possible mixture, such as one tablespoon per gallon. It is advisable to test this weak solution on a small patch of the target plant and wait a few days to check for any negative reactions before treating the entire area.
The timing of application plays a significant role in preventing plant damage. Avoid applying the liquid fertilizer during the hottest part of the day or when plants are under drought stress. Applying the solution in the early morning or late afternoon allows the plant time to absorb the nutrients before the sun can rapidly evaporate the water, which would leave concentrated salts on the leaf surface.