Everything You Need To Know About Fertilizing Houseplants

To feed, or not to feed? That is the question. A question we're asked almost every day here at the garden center. Other questions we often get include (but are not limited to): how much to feed, when to feed, and what to feed. When it comes to caring for houseplants, it's clear that fertilization is a common source of confusion. That's why we've put together a trusty guide to feeding houseplants, so they're always their biggest and brightest!

Fertilizing Houseplants 101

Unlike our garden plants, houseplants live in a pretty confined place, with soil that doesn't get replenished with nutrients unless we add them ourselves. Fertilizers provide plants with essential nutrients required for plant growth and bud-formation. But, just because fertilizers are meant to encourage lush foliage and beautiful blooms, doesn't mean they're meant for all plants-some houseplants actually thrive in poor soils and will suffer if fertilized! The perfect fertilizer and dosage combination is truly individual to the plant itself, so it's important to check the care instruction card of any new plants you bring home.

First and foremost, always read the instruction label on your product before using it to ensure you're using the product safely and efficiently. As much as your plants might be a little lackluster without fertilizers, over-feeding is an equally, or even more dangerous, problem. Although it might come from good intentions, overfeeding plants changes the concentration of dissolved solids in the soil and can affect your plant's ability to take up water. This "burning" can lead to yellowing, browning, wilting foliage, leaf drop, and root rot.

In general, flowering plants will almost always appreciate fertilizers as they encourage the plant to put more energy into producing more buds and bigger, more vibrant blooms. Flowering annuals, in particular, rely on a consistent fertilizing schedule to fuel their dramatic displays. Feeding also depends on the type of potting soil you use. If you're using a high-quality soil mix that's already fortified with lots of organic material, you can probably hold off on the fertilizer for a few months until those nutrients need to be replenished. Now that winter is upon us at last here in North Dakota, most plants aren't actively putting energy into growing and flowering so you can cut back on feedings of indoor and overwintered plants.

Types of Fertilizers for Houseplants

With so many different types of fertilizers to choose from, each with different nutrient concentrations, picking the right one can be overwhelming if you aren't sure what to look for. Here's how you can choose which product is right for you and your precious plants:

Liquid fertilizers are common choices for houseplants, as they supply a consistent supply of nutrients that you can easily control. Since they need to be diluted in water, it's easy to combine them with your watering schedule, using them every time or every other time you water your houseplants, depending on the plant's needs. This way, you can easily slack off on fertilizers during the dormant winter period, or use them more frequently when your plant is in bloom.

Slow-release fertilizers are liquid fertilizers encapsulated inside a coating or shell that breaks down slowly over time. The shells have varying levels of thickness, meaning their break down is staggered, and your plant gets a continuous, low dose over a long period. These have quickly become favorites amongst North Dakota houseplant owners as a single application can last for up to 9 months!

Fertilizer spikes and pills can also be embedded in your containers for a continuous supply of nutrients. The drawback with spikes and pills is that you can't really control at what rate the fertilizer is released, and they don't distribute nutrients evenly throughout the soil. So, while they're an option, they aren't the best fertilizers for your houseplants.

Granular fertilizers are dry pellets that are mixed in with the soil itself. The granules release fertilizer when the plant is watered, giving the soil a pretty big dump of nutrients at once. Granular fertilizers are meant for outdoor use in the garden and aren't the best choice for feeding potted plants or houseplants.

Decoding the N-P-K Ratio

Most fertilizer will have a 3-number ratio on them, indicating the ratio of each nutrient (nitrogen, phosphorus, and potassium, respectively) that the product supplies. Each of these nutrients is important to plants for different reasons as they each support a different function.

Nitrogen, the first number in the ratio, is an essential component of chlorophyll, the green pigment in plants. Chlorophyll is needed for photosynthesis, which you might remember from middle school science as the process that plants use light energy to fuel themselves. Basically, nitrogen is vital for healthy foliage and plant growth. High nitrogen fertilizers are especially useful for leafy plants, like philodendron and pothos.

Phosphorus, the middle number, is required for root growth and for transferring energy from the roots to the rest of the plant. It's useful for plants that fruit or flower, like begonias and African violets. Phosphorus encourages healthy rooting and strong bud formation.

Potassium, the final number of the sequence, helps to boost all-around plant vigor, stimulating plant growth and encouraging healthy blooms.

For the most part, all-purpose fertilizers with equal concentrations, like 10-10-10 or 20-20-20, will provide your houseplants with an abundance of essential nutrients that target all areas of the plant. When you get into large, leafy plants or ones with dramatic blooming, you can start to think about differing N-P-K ratios.

Houseplants provide our homes with so much life and beauty, but it's on us to nurture them and keep them that way. Choosing the right fertilizer is crucial for healthy growth and gorgeous, long-lasting flowers. Now, you can head to the garden center with the knowledge you need to pick the right one for your plants. If you're still a little unsure, don't hesitate to chat with one of our experienced houseplant enthusiasts at Plant Perfect in Bismarck!

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