While many people remember to water their indoor plants, they often overlook fertilizing them, which is essential to keep houseplants thriving. Fertilizing provides plants with vital minerals, which can diminish over time as watering leaches nutrients out of the soil. Since a potted plant depends entirely on its container for nutrients, it’s important to regularly replenish what it needs to stay healthy.
Fertilizer vs. Plant Food
Fertilizer is often marketed as “plant food,” but it’s important to know that plants make their own food through photosynthesis. Fertilizer simply provides the essential nutrients they need to function and grow. Think of it as the fuel that supports all other plant processes.
Macronutrients in Fertilizers
The primary nutrients in fertilizers are nitrogen (N), phosphorus (P), and potassium (K), collectively known as macronutrients. The ratio of these nutrients is listed on fertilizer packages in this order, such as 10-5-9 or 10-10-10, representing the amount of each nutrient in the mix.
Nitrogen
Phosphorus
Supports flowering, bud formation, and fruiting. Fertilizers with a higher middle number are best for flowering plants.
Potassium
Strengthens root function and moisture transport, which is beneficial for plant health.
Micronutrients in Fertilizers
Plants also need trace amounts of other minerals, known as micronutrients, including calcium, magnesium, sulfur, iron, and manganese. These are essential in small amounts and can typically be found in most commercial fertilizers.
Understanding Complete and Balanced Fertilizers
A “complete” fertilizer includes all three macronutrients (N, P, K), while a “balanced” fertilizer contains equal parts of each nutrient, like a 7-7-7 ratio.
Important Tips
Don’t fertilize dry soil
Always water the plant first or apply very diluted fertilizer to avoid root burn. If the plant has wilted from lack of water, rehydrate it and let it recover before fertilizing..
Avoid fertilizing stressed plants
If your plant is dealing with pests or other issues, wait until it has recovered before feeding.
When to Feed Your Houseplant
To know when to fertilize your houseplant, it’s best to understand its specific needs. Different types of plants require different feeding routines—flowering plants often need different nutrients than foliage plants, while succulents and cacti generally require less fertilizer.
General Guidelines
In general, houseplants should be fertilized during their active growing season, which is typically spring through fall. Winter-blooming plants, however, may need feeding during cooler months. Creating a schedule for feeding ensures consistency during the growing season. Remember that some plants are heavier feeders and may require more frequent fertilization.
Newly purchased plants or those recently repotted in fresh potting mix don’t need immediate fertilizing, as fresh soil contains nutrients. However, after about a month, the nutrients in the soil start to diminish, so consider starting a regular fertilizing schedule then..