Best Fertilizer for Indoor Plants — Which House Plant Fertilizer?

Last Updated on November 3, 2021 by Grow with Bovees

Growing indoor houseplants isn’t always as easy as it seems, because, as you are probably well aware, there are several factors that come into play for successful plant growth. 

Just like you and me, indoor plants need to be fed in a timely manner to thrive, and it all starts with choosing the right houseplant fertilizer. 

Unlike outdoor plants that receive much of their nutrient intake from the sun and rain, the nutrients provided to indoor plants are limited to the soil and fertilizer in the pot.

Even though some fortified potting soils are rich in minerals and other enhancements, you will have to fertilize the soil after a couple of months when the plants have consumed the nutrients in the soil.

What’s In Houseplant Fertilizers? 

High-quality houseplant fertilizers contain a great mineral balance of both micro and macro-nutrients.

These essential minerals are represented by the N-P-K ratio-nitrogen, phosphorous, and potassium, and are listed on the label of the respective fertilizer. 

An excess mineral ratio can affect the growth of plants, which is why it is highly important to pay attention to the amounts of nutrients in the fertilizer. 

Adding to this, the ratio of nutrients found in the best organic lawn fertilizer is different from the N-P-K ratio of houseplant fertilizer, because these two groups of plants have different nutrient needs. 

This means that you can’t use a lawn fertilizer to feed your houseplants, because it will probably not result in healthy growth. 

To break down the N-P-K ratio, the middle number stands for phosphorous, a macronutrient that’s essential for flowering.

So, if you have flowering houseplants, you should look for a fertilizer with a slightly higher amount of phosphorous for active growth. 

Contrarily, if you have non-flowering houseplants, buy a fertilizer that’s slightly higher in nitrogen (first number).

Apart from these critical nutrients, some fertilizers contain both micro-nutrients like iron, zinc, and boron, and macronutrients such as calcium and magnesium. 

Although micronutrients are present in smaller amounts than macronutrients, these crucial nutrients are important for the growth of roots and growth of stems and leaves in certain plants. 

Types of Indoor Plant Fertilizer 

Now that you’re aware of the essential nutrients in houseplant fertilizers, it’s time to know about the different types of fertilizer for indoor plants available to determine which one is right for you. 

There are myriad different varieties of indoor fertilizers to choose from-sticks, liquids, tablets, granules, fast and slow-release forms, making it tricky to get the right one for your indoor plants. 

Liquid Houseplant Fertilizer 

Liquids are the most common, cost-effective fertilizers, and simply need to be diluted with a little or a lot of water depending on your plant’s healthy growth needs. 

But on the downside, liquid fertilizers need to be used more frequently than their granular counterparts, but, on a brighter note, offer a reduced risk of fertilizer burn. 

There are several types of houseplant fertilizers available, but the preferred choice for most avid gardeners is Miracle-Gro or organic fertilizer for houseplants and trees. 

Even though organic liquid fertilizers take a bit longer to work, they do provide a steady stream of nutrients, making them a great solution to feed your indoor houseplants. 

Adding to this, they are also easier to control, meaning you can stop feeding when the plant goes dormant in the winter months, and continue feeding during the period of active growth. 

Granular Houseplant Fertilizer 

Granular houseplant fertilizers come in the form of pellets, and work well during active growth periods.

They can be mixed with potting soil by hand, and are most commonly used in outdoor gardens, but can also be used in indoor plant containers.

Granular houseplant fertilizers are available as granular pellets or compressed spikes, where the former are sprinkled on the surface of the soil, and the latter pushed down into the soil to get in close contact with the roots of the plant.

Just like liquid fertilizers, there are both organic and chemical granular options available, but again, organic is an excellent choice for most indoor gardeners. 

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Granular organic plant fertilizer contains naturally derived ingredients such as sulfate of potash, dehydrated worm castings, blood meal, bone meal, rock phosphate, limestone, and plant-based natural ingredients. 

If the label on the container of fertilizer doesn’t have an ingredient list of all the nutrients, then great chances are that it’s a synthetic concentration of fertilizer. 

Granules are best used when repotting a plant in fresh potting soil, and release essential nutrients when you water the plant. 

The water aids with nutrient absorption by transporting the granular fertilizer from the top layer of potting soil to the root zone of the plants. 

Slow-release Houseplant Fertilizers

Just as the name would suggest, slow-release fertilizers offer gradual fertilizer delivery to the houseplants.

Also dubbed time-release fertilizers, slow-release fertilizers contain a synthetic source of nutrients that are tucked away in a coating. 

This coating gradually breaks down and slowly releases the nutrients in low doses over a long period of time, so you will have to feed them only a couple of times or so per year. 

Slow-release fertilizer bottles and packages are a highly convenient way to feed houseplants, but most do not contain eco-friendly ingredients. 

When to Fertilize Houseplants? 

Now that you know about the different types of fertilizer options available to feed houseplants, it’s important to figure out the right time to fertilize your indoor plants. 

Determining when to feed houseplants is actually fairly easy, and the rule of thumb is to fertilize after the first frost to prepare your houseplants for the spring and summer ahead. 

Houseplants generally go dormant or semi-dormant during the winter, and therefore they do not need fertilizer. 

If you fertilize houseplants at this time, the plants will not absorb the nutrients, and in fact, will make them more susceptible to diseases and insects. 

However, this also depends on the type of houseplant, because ones that continuously grow through the winter, such as aloe vera and snake plants, should be fertilized less at the rate of ½ or ¼ as much in the winter as you would in the summer. 

Start feeding dormant and semi-dormant plants at the end of February.

Adding fertilizer to potting soil may not be a good idea unless the label says it’s safe to go this route, because most potting soils often have fertilizer in them, and adding more could result in fertilizer burn. 

How Often to Fertilize Indoor Plants? 

It is recommended that you follow the instructions on the fertilizer label, and how often you should fertilize indoor plants boils down to the fertilizer you’re using. 

If you’re feeding liquid fertilizer, some products should be used just once or twice a month, and others each time you water the houseplants. 

You should also pay attention to the ratio of fertilizer to cups of water, which is usually indicated clearly on most fertilizer labels. 

Granular fertilizers need to be applied more frequently because they release quickly into the soil, hence are digested by the plants more quickly. 

Slow-release fertilizers, spikes, and pods tend to last a couple of months or more, depending on how much you use, and the size of your indoor plants. Again, for all types of fertilizers, follow the manufacturer’s usage instructions. 

How to Fertilize Indoor Plants? 

This depends on the type of fertilizer you’re using, but here are some general guidelines.

Liquid fertilizers are available in several NPK ratios and can be mixed with any other nutrients your soil needs. 

You usually don’t need to use a lot of liquid fertilizer, but a teaspoon or a tablespoon should be enough.

Some liquid fertilizers can be applied directly to the green leaves of your houseplants, whereas others are meant to be applied directly to the roots. 

Organic liquid fertilizers are generally concentrated, so you will have to make a diluted solution and spray either on the roots or leaves of the plants for effective nutrient absorption. 

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With granular fertilizers, you have to first and, most importantly, measure carefully, and then mix into the top one or two inches of soil. 

As mentioned earlier, the nutrients of granular fertilizers are absorbed pretty quickly by indoor plants, so make sure you feed enough granules for the entire root system. 

Granular fertilizers can also be mixed in with fresh soil when transplanting or repotting a plant, but read the manufacturer’s directions before use. 

Slow-release fertilizers should be inserted directly and should be placed a couple of inches into the soil. 

9 Best Indoor Plant Fertilizers

Miracle-Gro Indoor Plant Food — Best Spray Fertilizer for Plants 

The Miracle-Gro indoor house plant fertilizer is great to use with all types of indoor plants including edibles, and flowering plants, a hoya krimson queen, for example.

This liquid plant food comes in a handy spray bottle, and contains 1 percent nitrogen, 1 percent phosphate, and 1 percent potash, and is easy to use, and ready to apply as soon as it arrives. 

The Miracle-Gro spray indoor plant fertilizer for plants should be sprayed twice for small pots, and 5 sprays for larger pots, so that it reaches the plant roots.

Jobe’s Houseplant Indoor Fertilizer — Best Spikes for Active Growth 

Jobe’s houseplant fertilizer spikes offer a great balance of nitrogen and minerals.

It is an easy way to keep your houseplants healthy and delivers a continuous supply of nutrients right at the roots. 

These pre-measured specially formulated spikes can be simply inserted into the soil around your houseplants. 

The N-P-K ratio of Jobe’s spikes is 13:4:5, making it a great choice for all your indoor plants.

It is one of the better quality fertilizers available today that unlike liquid and granular fertilizers eliminates messes, hazards, and smells, and doesn’t wash away when you add cups of water. 

Jobe’s spikes should be applied every 8 weeks, and each package contains 50 spikes. 

Joyful Dirt Organic Premium Concentrated Houseplant Fertilizer — Best Concentrated Fertilizer 

For an organic balanced fertilizer that contains beneficial microbes as well, you really can’t go wrong with the Joyful Dirt organic concentrated fertilizer for potted plants. 

It is one of the few organic fertilizers that’s specially formulated to feed all kinds of plants indoors but is not recommended for outdoor plants.

The Joyful Dirt organic fertilizer comes in a convenient shaker bottle for easy application to your indoor potted plants. 

You can either apply this indoor plant food directly onto the soil on each side of the plants or mix it directly into your watering can.

The Joyful Dirt concentrated organic fertilizer is to be applied once a month, and a little more often for unhealthy plants. 

It contains Mycorrhizae, and other growth enhancers, and has a 3-1-2 N-P-K ratio.

The Joyful Dirt fertilizer is safe to use around kids and pets and claims to produce more vibrant and larger houseplants. 

The Grow Co Fiddle Leaf Fig Tree Plant Food — Best Fig 

The Grow Co Fig Tree plant food offers a continuous supply of nutrients for all ficus varieties.

The slow-release fertilizer promotes strong root growth, and the right amount of vitamins and minerals for your outdoor and potted plants, resulting in beautiful plants on your property. 

The Grow Co slow-release fertilizer is a great alternative to liquid fertilizer and is an easy-to-use formula that greatly reduces fertilizer burns in indoor and outdoor plants.

A single application of this plant food feeds your ficus trees for up to six months and can be mixed with the top couple of inches of the soil. 

LiquiDirt Nano Organic All-Purpose Fertilizer — Best Organic Fertilizer for Leaf Shine and Brown Leaf Tips 

The LiquiDirt has an all-natural ingredient list that includes poultry, litter, rabbit manure, bat guano, worm castings, humic shale, oyster shell, and kelp meal. 

This organic, nutrient-rich all-purpose plant food can be used for all types of plants including heavy feeders and is a pH-balanced formula. 

LiquiDirt all-purpose plant food doesn’t expire ever and stays good until you use it, and is made based on the company’s Zymology process. 

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This power fertilizer is 100 percent water-soluble and should be added to water to make a super concentrate. 

Osmocote PotShots Slow-Release Fertilizer — Best Slow-Release Fertilizer 

Osmocote PotShots is one of the best slow-release fertilizers in the market and is specially formulated for potted plants.

These pre-measured food nuggets contain a great blend of essential nutrients and can feed your indoor and outdoor container plants for up to six months. 

This slow-release organic liquid organic houseplant fertilizer should be used twice per year, making it an easy and convenient way of feeding your houseplants. 

Osmocote PotShots liquid plant food contains homogeneous granules topped with a proprietary slow-release coating derived from soybean oil, which ensures great nutrient absorption for your plants. 

Each package of this indoor plant food contains 25 nuggets, and each nugget should be placed halfway between the edge of the container and your plant’s stem.

Lastly, push each nugget one to three inches deep into the soil, and then water. 

Miracle-Gro Spikes — Great For Flowering Plants

Unlike the Miracle-Gro liquid plant food mentioned above, Miracle-Gro indoor plant food spikes are a perfect choice for the continuous feeding of plants.

This (2 Pack) Miracle-Gro offers great value for money, given that you get not one but two-2.2 ounce packages. 

It is billed as one of the best fertilizers for houseplants, and its primary macronutrients are geared towards creating strong roots in houseplants. 

When applied to your common houseplant properly, Miracle-Gro spikes will last up to 2 months.

The spikes should be replaced every 30 days in the spring and summer, and every 60 days in the winter and fall. 

Each spike should be planted in each hole and pushed down until it is covered by the soil.

It features a 6:12:6 N-P-K ratio and is a great choice for all indoor flowering plants and foliage houseplants. 

Alaska Fish Fertilizer 

Alaska fish liquid fertilizer is infused with nutrients derived from fish to provide your houseplants with strong, healthy, and natural growth. 

Apart from slowly releasing fertilizer to your plants, Alaska fish fertilizer also considerably improves your soil’s structure and condition. 

This fish-based fertilizer is available in a plastic bottle and is great for use in vegetable and flower gardens.

It has a 5-1-1 N-P-K ratio and is OMRI listed for organic gardening. 

Aquatic Arts Philodendron Fertilizer

If you have beautiful philodendrons growing in your home, Philodendron Fertilizer is your best friend.

It has a 3-1-2 N-P-K ratio and is formulated to deliver nutrients to the soil and roots of your houseplants. 

It’s a good choice for many varieties of philodendrons including velvet philodendrons and philo pink princess

Philodendron Fertilizer is nutrient-rich and comes in an 8 Oz bottle.

This 8-ounce bottle lasts roughly a year and should be used once a month. 

Final Thoughts 

Feeding houseplants can be tricky, and knowing when to feed them can be even more challenging.

There are several ways to tell if your plants need fertilizer or plant food, such as wilting, pale, and lanky leaves.

The best type of houseplant fertilizer depends on your houseplant’s needs, so choosing the right fertilizer for indoor plants can be confusing. 

The good news is that most of the common houseplants have similar feeding needs, but some plants can be heavier feeders than others. 

With regards to the houseplant fertilizer schedule, it’s best to refer to the instructions on the label before application.

Compost tea is a great source of nutrients, but it doesn’t always make the best indoor plant food due to the fact that it often stinks terrible! It’s better used for fertilizing plants outside rather than on your tropical plants indoors.

Some houseplant fertilizers are available in a bottle for storage purposes and easy use, whereas others come in sealed packages. As long as you use the right products, fertilizing houseplants is an easy task.