Calla lilies are admired for their elegant, chalice-shaped blooms and vibrant colors. Proper nutrition is important for their robust growth, healthy foliage, and abundant flowering, as fertilization supplies essential nutrients.
Selecting Calla Lily Fertilizer
A balanced NPK (Nitrogen, Phosphorus, Potassium) ratio, such as 10-10-10 or 20-20-20, is often suitable for overall plant health. Nitrogen promotes lush foliage, while phosphorus is important for strong root development and prolific flower production. Potassium supports general plant health and disease resistance. Some gardeners opt for fertilizers with a slightly higher phosphorus content, such as a 5-10-10 ratio, to encourage more blooms and less excessive foliage growth. High nitrogen formulas can sometimes lead to abundant leaves at the expense of flowers. Beyond NPK, trace elements like magnesium, iron, and calcium also contribute to plant health.
Fertilizers come in various forms, each with distinct application methods and release rates. Liquid fertilizers are fast-acting and deliver nutrients quickly, making them suitable for regular feeding during the growing season. Granular fertilizers, including slow-release types, release nutrients over a longer period, requiring less frequent application. Organic options such as compost, bone meal, or well-rotted manure enrich the soil, improve its structure, and provide a gradual nutrient supply. Bone meal, specifically, is rich in phosphorus and calcium, which can enhance blooming and root health.
Fertilizing Schedule and Application
Correct fertilization timing is important for calla lily health and blooming. The general approach involves fertilizing during their active growth phase, typically from spring through early summer. An initial application of a balanced fertilizer can be made in early spring as new growth emerges to kick-start the season. As flower buds begin to appear, switching to a bloom-boosting fertilizer with higher phosphorus can encourage more vibrant and abundant flowers.
For calla lilies grown in containers, more frequent fertilization is generally necessary because nutrients can leach out with watering. Applying a water-soluble liquid fertilizer every two to four weeks during the growing season is often recommended for potted plants. In-ground calla lilies may benefit from a slow-release granular fertilizer applied once in spring, or regular feeding every four to six weeks during their active growth.
Regardless of the fertilizer type, proper application is important to prevent root burn and ensure nutrient absorption. Always water the plant thoroughly before applying fertilizer to moisten the soil; this helps dissolve the fertilizer for effective nutrient absorption. After application, water again to distribute nutrients and prevent concentration.
When using granular fertilizers, sprinkle them evenly around the base of the plant, avoiding direct contact with stems or leaves. For liquid fertilizers, dilute them according to package instructions before applying directly to the soil.
Troubleshooting Fertilization Issues
Both insufficient and excessive fertilization can cause problems, each with distinct symptoms. Under-fertilization can manifest as yellowing leaves, especially older ones, indicating a nitrogen deficiency. Weak or stunted growth, along with poor flowering or small, deformed blooms, may signal a lack of phosphorus. Yellow or brown leaf margins and reduced flowering can point to a potassium deficiency. If these signs appear, adjusting the fertilizer type or increasing the frequency of application during the growing season can help.
Conversely, over-fertilization can cause more immediate and severe issues. One common symptom is leaf burn, characterized by yellow or brown discoloration, particularly on leaf tips and edges. This occurs because high salt concentrations draw moisture from roots, leading to dehydration. Other signs include a white, crusty buildup on the soil surface, stunted growth despite fertilizer application, or excessive foliage with few or no blooms. In severe cases, roots may appear blackened or limp.
Promptly addressing over-fertilization minimizes damage. For potted plants, thoroughly flush the soil with ample water to leach out excess salts and nutrients. This involves allowing water to run through the pot and drain. For in-ground plants, a slow, steady trickle of water from a hose can help flush the soil around the plant’s base. Temporarily suspend further fertilization to allow the plant to recover. Removing any severely damaged foliage can help the plant redirect energy to new growth.