White clover (Trifolium repens) is a popular ground cover, valued for improving soil health and attracting pollinators. Common in lawns and gardens, this resilient plant is low-maintenance, but understanding its nutritional needs is important for success. This guide explains how to properly fertilize white clover.
Understanding White Clover’s Nutritional Needs
White clover fixes atmospheric nitrogen via a symbiotic relationship with Rhizobium bacteria in its root nodules. These bacteria convert nitrogen into a usable form, acting as a natural fertilizer producer. Thus, white clover does not require additional nitrogen. Excess nitrogen can hinder its growth by favoring competing grasses or suppressing its nitrogen-fixing capabilities.
While nitrogen is self-supplied, white clover still needs other nutrients. Phosphorus (P) and potassium (K) are important. Phosphorus aids root development and energy transfer, while potassium supports plant health and stress resistance. Micronutrients like molybdenum (Mo) and sulfur (S) are also beneficial. Molybdenum is essential for nitrogen fixation, and sulfur contributes to plant vigor.
The Importance of Soil Testing
Before fertilizing, a soil test effectively determines your soil’s nutrient status. A comprehensive test reveals nutrient levels, micronutrients, and pH. This prevents unnecessary fertilization, ensuring only required nutrients are added.
Soil testing kits or services are available through university extension offices or commercial laboratories. Results provide tailored recommendations. White clover thrives in soil with a pH between 6.0 and 7.0 (slightly acidic to neutral). Soil pH significantly impacts nutrient availability and Rhizobium bacteria effectiveness.
Choosing the Right Fertilizer Blend
Given white clover’s nitrogen-fixing ability, use fertilizers with low or zero nitrogen. Look for NPK (Nitrogen-Phosphorus-Potassium) ratios like 0-20-20, 0-10-10, or 0-0-28. The NPK ratio indicates nitrogen, phosphorus, and potassium content. These formulations provide needed phosphorus and potassium without excess nitrogen.
Fertilizers come in different forms. Granular fertilizers are slow-release, providing a steady nutrient supply and are easy to spread. Liquid fertilizers offer fast-acting delivery, quickly absorbed by foliage. Organic options, like bone meal or kelp meal, slowly release nutrients as they break down. Choose a blend that aligns with your soil test results to address deficiencies.
When and How to Apply Fertilizer
Fertilize white clover in early spring before active growth, or in fall for root development. Avoid winter application, as the plant is dormant and won’t utilize nutrients. Also avoid extremely hot days, which stress plants.
For granular fertilizers, use a broadcast spreader for even distribution. Water the area after application to help nutrients settle. Dilute liquid fertilizers according to instructions and apply with a sprayer; they are quickly absorbed through leaves. Always adhere to product label dosage to prevent over-fertilization, which harms clover and leads to nutrient runoff.
Clover Care in Various Landscapes
For pure white clover stands, provide adequate phosphorus and potassium while limiting nitrogen. This encourages dense, healthy growth. Maintaining optimal soil pH also supports nitrogen-fixing bacteria and plant vigor.
In mixed grass and clover lawns, fertilizing is challenging as grass requires more nitrogen. While a low-nitrogen NPK blend (e.g., 5-10-10) might support both, higher nitrogen levels favor grass over clover. Maintaining clover health in mixed settings involves ensuring sufficient phosphorus and potassium, allowing clover to naturally supply its own nitrogen.