August 6, 2025, 11:02 am | Read time: 3 minutes
The Calathea is known for being quite sensitive. Owners should take care to choose the right location and tend to it according to its needs. This includes fertilizing the Calathea. The plant’s nutrient requirements are moderate and vary with the seasons. Ignoring this can quickly upset the prayer plant, leading to its decline. myHOMEBOOK reveals what hobby gardeners should know.
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1. Mistake: Ignoring Growth and Dormant Phases
Many houseplants, such as the Calathea, go through so-called growth and dormant phases. During the growth phase, the plant actively grows, producing new leaves, flowers, or even fruits. This phase is usually in spring and summer, as they receive more light, it’s warmer, and they can better absorb nutrients.
In contrast, fall and winter are the dormant phases. To conserve energy, plants like the prayer plant pause their growth. During this time, houseplants should be watered less and not repotted. Additionally, houseplants like the Calathea should be fertilized sparingly or not at all during the dormant phase. Failing to adjust fertilization habits risks over-fertilizing the plant, which can cause long-term damage, such as root burn.
2. Mistake: More Fertilizer Helps More?
During the growth phase, the Calathea should be regularly supplied with nutrients. However, not too much! Over-fertilization from too frequent applications can lead to root burn. Brown leaf tips and whitish residues on the soil are typical symptoms.
It’s better to follow this guideline: From April to September, apply fertilizer every one to two weeks through the watering.
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3. Mistake: Using Mineral Fertilizers
An all-purpose liquid fertilizer is used as fertilizer. Ideally, a special fertilizer for tropical houseplants would be used–but it’s not a must. More importantly, hobby gardeners should avoid mineral fertilizers or those with high salt content. These are often intended for plants like tomatoes or cacti. While they help these plants grow, they primarily harm the prayer plant.
The Calathea has fine and sensitive roots that do not tolerate (too much) salt well. The roots are damaged by the salty soil, making it increasingly difficult for the plant to absorb nutrients. Since the Calathea can only be cultivated as a houseplant in this country, there is no way for rain to wash salts and excess nutrients into deeper soil layers in a pot.
By the way: The prayer plant can also be fertilized with coffee grounds. Make sure they are dry to prevent mold. Although this waste product still contains valuable nutrients like potassium, nitrogen, and phosphorus, it should not be used as the sole fertilizer. What hobby gardeners should consider when fertilizing with coffee grounds can be found in this article.
4. Mistake: Fertilizing Before Watering
Liquid fertilizer is ideal for the Calathea. The fertilizer can be easily applied through the watering. This not only dilutes the fertilizer but also prevents it from hitting dry soil. This is something to avoid at all costs. Fertilizing the prayer plant on dry soil can lead to root burn. It’s better to fertilize moist substrate.