For most plants, summer is the active growth season, which also holds true for houseplants. Because plant growth nutrients are limited in potting soil, fertilizing houseplants regularly during summer provides the nutrients they need to sustain this consistent growth. But exactly how often should you fertilize houseplants in the summer?
Houseplants should be fertilized at least once a month in the summer to sustain their active growth in the warmer months. However, you can fertilize fast-growing houseplants more often, especially when liquid fertilizers are used. Slow-growing houseplants are fertilized less frequently.
Since plants may not show immediate signs of low nutrients in the soil, the best approach is to follow a regular schedule so that your houseplant never lacks nutrients. To help you create a summer houseplant fertilizing schedule, this article will tell you what houseplant fertilizers are, how often you should apply them to your houseplant, and what types to use.
An Overview of Houseplant Fertilizers
There are many fertilizers, but not everyone is perfect for every kind of plant. Most plants will do fine with an all-purpose fertilizer. However, it’s best to stick to fertilizers made for houseplants.
Note that fertilizers are applied to plants to provide the essential macronutrients and micronutrients for healthy plant growth.
As their nomenclature suggests, houseplants consume the primary macronutrients in larger quantities than the micronutrients. Macronutrients are vital for overall plant health and growth. The primary macronutrients are nitrogen, phosphorus, and potassium. It’s indicated by the N-P-K ratio on the fertilizer’s packaging.
The NPK ratio tells you the percentage of each of the three macronutrients in the package. The ratio of macronutrients for garden plants differs from that of houseplants because these plants have different nutritional requirements. This is why it’s essential to use a fertilizer specifically formulated for houseplants.
When buying fertilizer for your houseplant, ensure it says it’s only for houseplants on the package. Take, for example, the popular Miracle-Gro Indoor Plant Food (available on Amazon.com). The product is labeled as “food for flowering and foliage houseplants” and has an NPK ratio of 6:12:6.
It’s also important to note that you can choose from various fertilizer types when buying your plant’s food. Which you choose will also change how often you apply fertilizer to your plants.
Types of Houseplant Fertilizers
Houseplant fertilizers are usually categorized by the mode of application. The two main fertilizers you’ll use on houseplants are granular and liquid formulas.
One option also isn’t necessarily better than the other. For instance, liquid fertilizers are better if your plant needs nutrients as soon as possible. Still, granular fertilizers can be more convenient if you don’t want to apply them as often.
Before choosing one, you’ll need to consider their key differences.
Granular Houseplant Fertilizers
Granular fertilizers are small, hard pellets that you apply to the upper layers of soil in the pot. Immediately after adding them, you should water the plant thoroughly to help the nutrients seep into the soil. You generally don’t need to apply it as frequently as liquid fertilizers.
This fertilizer also comes in two main forms: slow and quick release. Which you use will impact how often you fertilize your house plants during the summer.
Slow-release fertilizers deposit nutrients into the soil over time. You won’t need to give your houseplants more than one application a season because the fertilizer should provide nutrients for multiple months.
However, quick-release fertilizers add nutrients to the soil immediately. Your houseplants will quickly take in all the nutrients, leaving none in the soil for later. Generally, you’ll need to apply a quick-release fertilizer at least once a month for the best results.
If you’re not careful, you could accidentally overfeed your plants, so make sure you give them enough time between applications.
Liquid Houseplant Fertilizers
These fertilizers contain nitrogen, phosphorus, and potassium, although they’re in a liquid concentrated form. You’ll need to dilute the fertilizer with water so that you don’t use too much.
Since it’s a liquid, this fertilizer is almost always a quick-release formula. It’s also much easier for your plants to absorb the liquid, so you must apply it more often than granular fertilizers.
Since it’s quick releasing, you’ll want to offer it to your houseplants every two weeks during the summer. Your plants will absorb the nutrients quickly during their growing phases, making it important to replace them often.
Often, liquid fertilizers are also used as plant growth enhancers. These enhancers contain several ingredients that help boost plant growth, including:
- Plant micronutrients,
- Amino acids,
- Vitamins,
- Trace elements,
- and various plant hormones.
When used correctly, these fertilizers are perfect for enhancing the appearance of your plants and make them look greener. If you would like to learn more about using liquid fertilizer, check out my article: How to Use Liquid Plant Fertilizer (8 Essential Tips)
Can You Combine Granular and Liquid Fertilizers?
Many gardeners recommend against mixing granular and liquid fertilizers together. After using one, you’ll want to wait a while before switching to the other. This is because you don’t want to overload your houseplants with nutrients, even if they’re in a growing phase.
Since liquid fertilizers provide immediate nutrients and granular fertilizers deposit them in the soil over time, it’s easy to overfeed your plants. Your plants can react by developing brown, crunchy leaves or even wilting, so it’s important to be careful. Overfertilizing houseplants can also stunt their growth, which is the opposite of what you’re trying to achieve.
Why Houseplants Need Fertilizer in Summer
All plants consume nutrients from the soil through their root system. However, potted plants don’t have access to the nutrients naturally occurring in the ground. Once they deplete the vitamins and minerals in their pots, you’ll be required to fertilize them to restore plant growth nutrients in the soil. Otherwise, there’s no way for them to get more nutrients.
As with garden plants, potted houseplants consume soil nutrients at varied rates in different seasons. Since the increased warmth of the sun in summer promotes rapid growth, plants consume more nutrients in this period. Houseplants need regular fertilizer in summer rather than during their slow-growth periods in winter.
What Happens If You Don’t Use Fertilizer?
Your houseplants experience a significant growth boost during the summer. If they don’t have the nutrients they need to grow, they’ll stop. It can also lead to nutrient deficiencies, which causes several health problems in plants.
Your flowering plants won’t be able to bloom as well, either, since they need a lot of nutrients to make flowers.
Nutrient deficiencies in houseplants can come with these symptoms:
- Yellowing or browning leaves
- Leaves appear crunchy or burned
- Leaves becoming warped, curled, or distorted in other ways
- Excessively dropping leaves
- Wilting
Using fertilizer can undo many of these symptoms and prevent your plant from dying, as long as you act quickly enough. Since your plants can’t access endless nutrients in the earth, they rely on you to provide them with fertilizers during their growing periods.
Summer Houseplant Fertilizer Application Guidelines
How often you fertilize your houseplant will depend on the type of plant. For example, fast-growing plants with large leaves or those that bloom a lot, like roses and hydrangeas, will need more frequent fertilizing.
You’ll need to consider the type of fertilizer you’re using and whether it’s a slow or quick-release formula. Here’s a quick breakdown of when you should apply each kind of fertilizer:
- Slow-release granular fertilizer: You only need to use slow-release pellets every four months, so one application should last your houseplants the entire summer.
- Quick-release granular fertilizer: You should apply these pellets at least once a month during the summer.
- Liquid fertilizer: You’ll need to use this fertilizer the most often. Since this fertilizer is easy for your plants to drink immediately, you should apply it every two to three weeks during the summer.
Some plants also grow faster than others, meaning you’ll want to slightly increase the frequency of fertilizing them.
These summer houseplant fertilizer application guidelines should be followed regardless of whether your houseplant stays indoors or you bring it outdoors for the summer. Plants will experience the brighter summer sunlight and grow faster in the warmer months, whether they’re indoors or outdoors.
Houseplant Summer Fertilizer Application Schedule
In summary, here’s what a houseplant summer fertilizer application schedule would look like considering plant growth rate and climate conditions:
| Climate and Plant Factors | Summer Fertilizer Application Schedule | Plant Examples |
| Tropical climate |
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| Houseplants that grow fast in summer |
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| Slow-growing plants |
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Final Thoughts
Houseplants are receptive to the warmer summer weather. This facilitates their rapid growth during these months.
Because houseplants have limited nutrients in the potting soil, they must provide sufficient nutrients in the growing season using fertilizers.
You can choose between granular, liquid, slow-release, or homemade organic fertilizers. In either case, the rule of thumb is to manure your houseplant at least once every month.
The number of times you fertilize your houseplant in the summer should increase if you use liquid fertilizers or if your houseplant qualifies as a fast-growing plant.
