With springtime springing on us, we have been getting lots of questions in about houseplant fertilizing. When, howand why to fertilize your houseplants are all worthy questions that can help you level up your houseplant care, so we've decided to put together a little houseplant fertilizing 101 guide for you!

Here, we unravel the mystery of what fertilizer is and what it does for your plants, and present a list of 5 fertilizing tips to get started so you can confidently turn your thumb a deeper shade of green this spring.

Spring Feeding: Houseplant Fertilizing 101 - Pistils Nursery

Houseplant Fertilizing 101

What is Fertilizer?

Although the name is a bit misleading, fertilizer isn’t actually “Plant Food.”  Rather, plants make their own food using sunlight in a process called photosynthesis.

Fertilizer is more like a multi-vitamin for your plants with essential nutrients. In a natural environment, these essential nutrients get replenished in the soil from decomposition of organic material and weathering of rocks over time.

In our homes, however, the nutrients in the soil of our potted plants get depleted over time, as our plant friends use them. This is why it is important to refresh soil and add fertilizer when appropriate.

The Chemistry

You don’t need a degree in chemistry to understand your fertilizer label, but it is helpful to have a basic understanding of what each component does for your plant.

The main nutrients found in houseplant fertilizer are Nitrogen (N), Phosphorus (P), and Potassium (K), which are the fundamental nutrients your plant will need. These are called macronutrients and will be seen on labels in the form of a numeric ratio. For example, a package that says 10:4:3 means the fertilizer contains 10 parts Nitrogen, 4 parts Phosphorus, and 3 parts Potassium.

Here is a breakdown of the main nutrients and why they are important:

  • Nitrogen (N): Promotes plant growth
  • Phosphorus (P): Formation of roots, flowers, and fruit
  • Potassium (K): Resistance to disease and stress, hardiness for winter dormancy

Other beneficial nutrients found in fertilizers are calcium, magnesium, and iron. These are referred to as micronutrients on fertilizer labels. 

5 Tips to get started Fertilizing Houseplants 

  1. Read the label: There are many different types of plant fertilizers with different nutrient ratios, so it is very important to read the label carefully and make sure you are giving your plant the correct balance of nutrients. Fertilizers can be solid, liquid, slow release, specific for one plant type, organic, or chemical. The first step is to understand what you are using, the type of plants the product is intended for, and the purpose of that specific fertilizer.
  2. Less is more: Dilute your fertilizer more than the label recommends. You can always add more fertilizer but you cannot take any back once used. Adding too much fertilizer can cause damage called “fertilizer burn” that can lead to death of your plants if it goes untreated. (Treat fertilizer burn by flushing your pot thoroughly with water, or repotting in fresh soil).
  3. Timing: It is important to fertilize only when your plant is actively growing and never in times of dormancy. It is best to fertilize your plants in the springtime because this is when they are growing the most and therefore using the nutrients we give them the fastest. Hold off on fertilizing in the winter, when your plants are more or less dormant.
  4. Know your plants: Some plants require specialty fertilizer with a specific balance of nutrients that they can use. Examples of plants that need special fertilizers include: cacti, succulents, carnivorous plants, and epiphytic plants such as orchids. Do a little research on what kind of fertilizer is best for your specialty plant before feeding. 
  5. Wait after repotting: When you repot a plant, its roots are more vulnerable to fertilizer burn. Wait a few weeks before fertilizing to give your plant time to adjust to its new home. Keep in mind plants recently repotted will have nutrients refreshed from the new soil, so fertilize them sparingly. Springtime is an ideal time to both repot plants and fertilize them – but not at the same time!

What Houseplant Fertilizer We Use at Pistils

  • Good Dirt Plant Biotics: Micro-organisms convert nutrients into usable forms for plants and create a healthier soil. When used early enough, this can help plants be better prepared for stresses like moving, cold weather, and unpredictable pests. To use: add a light dusting to the top of the soil before watering.
  • Good Dirt Plant Food: This is our go-to gentle liquid fertilizer for indoor and outdoor plants. To use for indoor plants, add one pump per gallon of water, for outdoor plants use two pumps per gallon of water when watering.
  • BGI Garden Gain All Purpose Plant Food: This is a slow release granular fertilizer with both macro and micronutrients that will fertilize one 10” plant or two to three 6” plants for up to 4 months. To use, work indicated amount evenly into surface soil and water thoroughly. Every time you water, a little more nutrients are released.
  • Modern Botanical Liquid Nutrients: This water-soluble gentle fertilizer is designed for hydroponics, but we love it for all houseplant applications. We put a few drops in our watering cans, to help grow our plant cuttings, in semi-hydro setups with LECA, and more!
  • Air Plant Fertilizer: This foliar spray was designed with air plants in mind. Spray onto the leaves of Tillandsia, Staghorn ferns, and other plants that absorb water and nutrients through their leaves.

Spring Feeding: Houseplant fertilization 100 - Pistils Nursery

Time waits for no one, and with spring in full swing the time is now to start fertilizing and refreshing soil, so our houseplants have what they need to grow big and strong this year.

Our plants grow the most during spring and continue their growth into the summer, starting to slow down in the fall for their more dormant winter rest. Keep this in mind when adding fertilizer to your care regimen; starting strong in the spring and summer, slowly winding down into the fall, and leave them be for the winter.

Be thoughtful and mindful with your plants so we can keep them and our thumbs a vibrant color green.

Words by Brittany Oxford

Pistils Nursery