Peace lilies, celebrated for their elegant white “blooms”—which are actually modified leaves called spathes—and their ability to purify indoor air, are popular houseplants. While relatively low-maintenance, proper fertilization is important for their sustained health and to encourage flowering. This guide offers insights into effectively fertilizing peace lilies.
Understanding Peace Lily Fertilization Needs
Peace lilies benefit from fertilization to replenish essential nutrients in their potting mix, which naturally deplete over time. This nutrient boost supports vigorous growth and flowering. The most suitable time to fertilize peace lilies is during their active growing season, from spring through summer. During this period, the plant expends more energy and efficiently absorbs additional nutrients.
Signs a peace lily might benefit from fertilizer include slow growth, a lack of blooms, or pale and yellowing leaves. However, yellowing leaves, especially older ones, can also indicate other issues like improper watering, so assess the plant’s overall condition before assuming a nutrient deficiency. It is not recommended to fertilize peace lilies during their dormancy in winter, when growth slows, or if the plant is stressed, such as after repotting. Fertilizing during these times can lead to a buildup of mineral salts in the soil, potentially harming the roots.
Selecting the Best Fertilizer
A balanced, water-soluble houseplant fertilizer is often recommended, such as a 10-10-10 or 20-20-20 NPK (Nitrogen-Phosphorus-Potassium) ratio. These numbers indicate the percentage of each primary macronutrient by weight. Nitrogen promotes lush green foliage, phosphorus supports root and flower development, and potassium aids in overall cellular function. Some experts also suggest a fertilizer with a slightly higher nitrogen content to support leaf production, though too much nitrogen can sometimes reduce flowering.
Liquid fertilizers are a common choice because they deliver nutrients quickly and are straightforward to use. They are mixed with water and applied directly to the soil, offering an immediate nutrient boost. Slow-release options, typically in pellet form, provide a gradual supply of nutrients over several months as their coating dissolves. While convenient for less frequent application, the rate of nutrient release can be less controllable. It is best to select a fertilizer specifically formulated for houseplants or flowering plants and avoid using outdoor garden fertilizers, which may be too concentrated for indoor plants.
Applying Fertilizer Correctly
When using liquid fertilizers, dilute them, typically to one-half or even one-quarter of the strength recommended on the product label. This dilution helps prevent over-fertilization and root burn (brown leaf tips and edges). Always mix the fertilizer thoroughly with water before application to ensure even distribution.
Fertilizer should always be applied to moist soil, never dry. Applying fertilizer to dry soil can cause root damage, as concentrated nutrients rapidly draw moisture away from the roots. After applying liquid fertilizer, watering can help distribute the nutrients evenly throughout the soil and around the roots. When using slow-release pellets, they are typically sprinkled on the soil surface or worked into the top layer. Avoid direct contact of fertilizer with the plant’s leaves, as this can cause burning. Always adhere to the specific dosage instructions provided by the fertilizer manufacturer, adjusting for the diluted strength and the size of your plant.
Troubleshooting Fertilization Problems
Even with careful application, peace lilies can sometimes show signs of fertilization issues. Over-fertilization is a common problem, often indicated by brown or crispy leaf tips and edges, stunted growth, or a white crust on the soil surface. This occurs when excess mineral salts accumulate in the soil, drawing moisture away from the plant’s roots. If these signs appear, flush the soil by watering the plant thoroughly with plain water, allowing it to drain completely. This process helps wash away excess salts, and it’s best to temporarily stop fertilizing for several months.
Conversely, under-fertilization can lead to pale green or yellowing leaves, particularly older ones, and a general lack of vigor or new growth. If nutrient deficiency is confirmed, gradually adjusting the feeding schedule and concentration can help. However, rule out other causes for these symptoms, such as improper watering or insufficient light, before increasing fertilizer. Observing your peace lily’s response to fertilization and making small adjustments to the routine can help maintain its health and encourage growth and blooms.