Yes, you absolutely should fertilize your Christmas cactus (Schlumbergera spp.). From our perspective as plants, fertilization is not merely an optional supplement; it is a critical component of replenishing the nutrients we deplete from our limited soil environment, especially when we are grown in containers. Proper feeding supports robust growth, strengthens our systems against stress, and is fundamental for producing the vibrant blooms you cherish.
Our fertilization needs are intrinsically tied to our natural growth and dormancy cycles. We are not in a constant state of growth. The year can be divided into key phases: an active growth period (spring and summer), a bloom preparation period (late summer to autumn), a flowering period (late autumn to winter), and a brief rest period after blooming. Fertilizer is the fuel for the active growth and bloom preparation stages, providing the essential building blocks for new stem segments (called cladodes) and, most importantly, flower buds.
Timing is everything. Providing nutrients when we are dormant can be harmful, encouraging weak growth at the wrong time.
Spring and Summer (Active Growth): Begin fertilizing us about a month after our spring flowering has finished. This is when longer days and warmer temperatures signal us to produce new growth. A regular feeding schedule of every two to four weeks with a balanced fertilizer is ideal during this period.
Late Summer and Early Fall (Bud Formation): This is the most crucial time to continue feeding. Our energy is focused on developing the flower buds that will bloom for the holidays. Ceasing fertilizer too early can limit our blooming potential.
Late Fall and Winter (Blooming and Dormancy): Once our flower buds are well-formed and we begin to bloom, you must stop fertilizing. We require a period of rest. Fertilizing during this time can disrupt our cycle and potentially cause buds to drop.
We are not heavy feeders, but we have specific preferences. A balanced, water-soluble fertilizer is excellent for our active growth phase. Look for a formula with equal or similar parts Nitrogen, Phosphorus, and Potassium (e.g., 10-10-10 or 20-20-20). Nitrogen promotes healthy green stem growth, while Phosphorus is vital for root development and flower production.
As we move into late summer, many gardeners have success switching to a fertilizer with a higher phosphorus ratio (e.g., 10-30-20) or a blossom-booster formula to further encourage bud set. However, a consistent balanced fertilizer throughout the growing season is also perfectly adequate. The key is to always apply it to moist soil to prevent root burn and to dilute it to half the strength recommended on the package label.
