The Best Fertilizer for a Peace Lily

The peace lily, or Spathiphyllum, is a favored houseplant admired for its deep green foliage and striking white blooms, which are a modified leaf called a spathe. While these plants are straightforward to maintain, achieving consistent flowering and lush leaves depends on proper nutrition. Providing the right nutrients supports the long-term vitality of your peace lily.

Peace Lily Nutrient Requirements

A peace lily’s health is supported by three primary macronutrients: nitrogen (N), phosphorus (P), and potassium (K). Nitrogen is fundamental for vegetative growth, contributing to the plant’s rich, green leaves. Phosphorus is involved in root development and the production of flowers, making it necessary for the plant’s signature white spathes. Potassium aids in general cellular functions, helping to regulate water and support the plant’s overall vigor and resistance to stress.

For most peace lilies, a balanced fertilizer with equal N-P-K ratio numbers, such as 10-10-10 or 20-20-20, is recommended. These numbers indicate the product contains an equal percentage by weight of each macronutrient. Quality fertilizers will also contain micronutrients like magnesium, calcium, and iron, which are needed in smaller quantities.

Types of Peace Lily Fertilizers

Fertilizers for peace lilies come in several forms, with the most common being water-soluble liquids or powders. This type is often preferred because it allows for precise control over concentration and application, ensuring an immediate nutrient boost. Since it is mixed with water, the fertilizer is distributed evenly throughout the soil, which helps prevent over-application.

Another option is slow-release fertilizer, which comes as pellets or granules mixed into the top layer of soil. These products break down gradually over several months, releasing a steady, low dose of nutrients each time the plant is watered. While convenient, this method offers less control and can lead to over-fertilization if too many granules dissolve at once.

Fertilizer spikes are another slow-release choice where solid sticks are pushed into the soil to dissolve over time. A drawback is that they concentrate nutrients in one spot, which may not distribute evenly and can risk burning nearby roots. For those who prefer natural methods, organic choices like compost tea or fish emulsion provide a gentler source of nutrients.

How and When to Fertilize

Peace lilies have distinct growing and dormant periods that dictate their nutrient needs. Fertilizing should be confined to the active growing season, which runs through spring and summer. During the fall and winter, the plant’s growth slows and it does not require supplemental feeding. A good schedule is to fertilize every 6 to 8 weeks during the growing months.

A primary rule for peace lilies is to fertilize weakly, as they are sensitive to high salt concentrations in the soil. It is recommended to dilute a balanced liquid fertilizer to half or even a quarter of the strength suggested on the product packaging. This reduced concentration provides sufficient nutrients without causing root burn.

Before applying fertilizer, first water the plant with plain water. Applying fertilizer to dry soil can scorch the roots, while moist soil helps ensure the nutrients are absorbed and distributed evenly. After watering, apply the fertilizer solution around the base of the plant until it drains from the bottom of the pot.

Signs of Improper Fertilization

A peace lily will often display visual signs if it is receiving too much or too little fertilizer. Over-fertilization is a common issue that leads to a buildup of mineral salts in the soil. This appears as brown, crispy tips or edges on the leaves. Other symptoms include the yellowing of lower leaves, wilting even when the soil is moist, and a visible white crust on the surface of the soil.

A plant that is not receiving enough nutrients will also show distinct signs of deficiency. The indicators include slow or stunted growth and leaves that appear pale green or yellow, a condition known as chlorosis, which can point to a lack of nitrogen. A consistent failure to produce its white flowers during the growing season is another indication that the plant may require more nutrients, particularly phosphorus.