Keep your houseplants thriving with careful attention to their fertilization needs. If your houseplant foliage becomes yellow, this indicates a zinc deficiency. Most fertilizers contain some zinc as a trace element; however, zinc is not a main ingredient in these fertilizers. If your houseplants exhibit a zinc deficiency, continue to use an all-purpose fertilizer and supplement these feedings with zinc sulphate. Monitor the condition of your plants and you should see marked improvement after supplementing with zinc.
Mix the all-purpose fertilizer with water, using half the recommended amount to make a half-strength fertilizer solution.
Move the houseplant to a sink or a tub for drainage.
Pour the mixed fertilizer around the roots of the houseplant until the fertilizer drains out the bottom of the container.
Measure the zinc sulphate according to package recommendations for the size of your growing container.
Sprinkle the zinc sulphate around the soil of the houseplant, taking care not to allow the fertilizer granules to touch the plant foliage.
Water the houseplant generously immediately after applying the zinc sulphate.