Keeping your indoor plants healthy isn’t difficult.
But it does take regular feeding with a good fertilizer to give them what they need.
Without it, your plants use up the available nutrients quickly. Leaving them prone to deficiencies, stunted growth, and a sickly appearance.
Our top choice is Miracle-Gro All Purpose Plant Food. It’s good for all indoor plants and produces quick results at an economical price.
The best fertilizer for indoor plants at a glance:
- Jobe’s Organics All Purpose Fertilizer Spikes
- Miracle-Gro All Purpose Plant Food
- Earthpods Natural Flower & Plant Food Capsules
- Osmocote Smart-Release Plant Food Plus
- Miracle-Gro Indoor Plant Food Spikes
- Aquatic Arts Indoor Plant Food
- Houseplant Resource Center Liquid Fertilizer
- Schultz All Purpose Plant Food Plus
- J R Peters Jack’s Classic All Purpose Plant Food
- Espoma Organic Indoor Plant Food
All links lead to Amazon, where you can find more information & customer reviews.
The Best Fertilizer For Indoor Plants: Reviews
Miracle-Gro All Purpose Plant Food
Miracle-Gro is a company with a good reputation for its fertilizer products.
This one comes in a powder that you dilute with water. Making a liquid fertilizer designed to quickly give your houseplants the nutrients they need for fast and healthy growth.
You can use it on container plants indoors and outdoors. And you can also use it to grow vegetables, trees, and shrubs.
It has a 24-8-16 NPK ratio. Providing a large amount of nitrogen for fast and strong growth. And a good amount of potassium, making your plants more resistant to disease. As well as increasing the yield of those that bear fruit.
Mix 1/2 a teaspoon per gallon of water before adding it to your watering can. With just 1 application every 1-2 weeks enough for spectacular results.
With even struggling plants rapidly growing and coming into bloom.
But you have to be careful to follow the instructions and not over-apply it because it can burn your plants.
Some customers also report using this successfully for hydroponics.
It comes in a 10 lbs container.
Jobe’s Organics All Purpose Fertilizer Spikes
These fertilizer spikes are organic and OMRI listed (Organic Materials Review Institute). They’re all-purpose, making them good for indoor houseplants, as well as flowers, shrubs, and fruit trees in your garden.
The fertilizer sticks break down slowly in the soil releasing the 4-4-4 NPK mix. And they contain all the essential secondary nutrients, calcium, sulfur, and magnesium. As well as a range of micronutrients. Making them a complete food for your plants.
Included in the mix is a proprietary blend of helpful microbes that Jobe’s call Biozome. This includes bacteria to enhance the biological activity of the soil. And a microorganism called Archaea that aggressively breaks down organic matter to release nutrients.
They’re easy to use. You stick them into soft soil, where they feed plants at the roots without any mess or waste.
Another big plus of this fertilizer is something it doesn’t have.
Unfortunately, most organic fertilizers have an unpleasant smell as they often contain animal manure. Which makes them less suitable for using indoors.
But these spikes are free of offensive odors. Making them one of the few natural fertilizers you can use for indoor gardening without having to hold your nose.
Customers report great results. With healthy green growth and beautiful flowers.
But there is one drawback:
Some dogs like to dig the spikes out of the soil and eat them. So if you have pets you’ll have to keep an eye on this.
They come in a resealable bag of 50 spikes. With 4 spikes recommended for use in an 8” pot, 8 for a 12” pot, and 16 for a 16” pot.
Earthpods Natural Flower & Plant Food Capsules
These eco-friendly fertilizer capsules are good to use on both indoor and outdoor plants. Including flowers, herbs, fruits, and vegetables.
They’re packed with a wide range of plant nutrients to make sure your plants have everything they need for healthy growth.
The NPK ratio is low at 0.2-0.2-0.4. But there’s a lot more to this product than that. With a full range of essential nutrients needed for plant growth included.
They also contain humic acid and fulvic acid. That help to make nutrients more available in the soil.
And they add beneficial bacteria and fungi to enhance the breakdown of organic matter and release of nutrients. While helping your plants roots to increase their nutrient uptake.
Over time, these capsules increase the quality of the soil your plants are sitting in. Stimulating strong root growth, and healthy stem development.
They’re easy to use. Just push 1 capsule beneath the soil near the stem of your plant every 14-21 days and water. They break down slowly, gradually releasing their nutrients.
Customers report results within weeks. With plants visibly perking up, new growth of green leaves, and flowers blooming.
The 100 capsule tub is enough to fertilize a single small houseplant for 5 years. With 1-2 capsules recommended for each small plant, 2-4 for each medium sized, and 4-8 for large plants.
The capsules are made in the USA, from natural and organic ingredients according to the company. But the product doesn’t seem to have any organic certification.
Osmocote Smart-Release Plant Food Plus Outdoor & Indoor
This granular fertilizer is designed by the company to be an all-in-one solution for fertilizing all plant varieties.
It has a 15-9-12 NPK formula. Containing high levels of nitrogen, phosphorus, and potassium for impressive growth, flowering, and fruiting.
It’s also fortified with the essential secondary macronutrients magnesium and sulfur. And 6 micronutrients, iron, zinc, molybdenum, boron, manganese, and copper. Making it good for correcting nutrient deficiencies in your soil.
The fertilizer comes in granules coated with a resin that controls the release of its nutrients gradually. Resulting in it feeding your plants for up to 6 months at a time.
It’s a synthetic fertilizer. So it has the same potential drawback that most of them have.
That is, it can burn your plants when used incorrectly. But the company guarantees no harm if you stick to the instructions.
The bottle of fertilizer comes in 3 sizes: 8 lbs, 2 lbs, and 1 lb.
As well as this product for indoor and outdoor plants, the same company does a special version for flowers and vegetables.
Miracle-Gro Indoor Plant Food Spikes
These effective, economical, and easy to use fertilizer spikes are one of the most popular products for fertilizing houseplants.
They have an NPK ratio of 6-12-6. Along with a good amount of nitrogen to fuel growth, it’s also high in phosphorus which helps plants to develop strong root systems. And in flowering plants, it encourages the production of flowers.
It also contains a good amount of potassium, for plant resistance to disease and drought. And to increase fruit yield and quality in fruiting plants.
The Miracle Aerator Spike included in the package makes it easy to create a small hole in your soil at the halfway point between the rim of the pot and the stem of the plant. You then place the spike in. And they dissolve gradually, with each one fertilizing for about 2 months in the winter and fall. While it’s recommended to replace them every 30 days in the summer.
Customers are impressed with the convenience of using these. If you often forget to mix and apply fertilizer, then placing these in your plant pot and forgetting about them can get you great results. With quick growth of stems and leaves, and happy thriving plants.
They come in a pack of 48 spikes. With 5 spikes recommended to use at a time in a 9” pot.
Aquatic Arts Indoor Plant Food
This fertilizer has a 16-5-11 NPK ratio. It’s particularly high in nitrogen for fast and vigorous growth, strong stems, and vibrant leaves.
It consists of pellets that dissolve slowly in the soil. Gradually and continuously releasing their nutrients.
This means you don’t need to mix it into the soil very often. With the product fertilizing your plants for up to a year at a time when used according to the instructions. Making it very convenient, particularly if you’re forgetful.
But at the same time, it works quickly. With the manufacturer claiming a faster response time than fertilizer spikes.
It’s made from 100% natural ingredients. But, it’s not certified organic.
The fertilizer comes in an 8 oz bag.
Houseplant Resource Center Liquid Fertilizer
This liquid fertilizer is good for all varieties of houseplants. Including Pothos, African Violets, Dracaena, Orchids, Succulents, Spider plants, philodendron, and more.
It has a 3-1-2 NPK ratio guaranteed by analysis. But it doesn’t provide secondary nutrients or micronutrients.
Because the nutrient content is not too strong it won’t overpower your plants. And you can use it up to once a week when you water.
The bottle contains 8 fluid ounces of fertilizer that you dilute before using.
Schultz All Purpose Plant Food Plus
This liquid plant food is for all indoor and outdoor plants. It has a 10-15-10 NPK formula. And it’s fortified with additional micronutrients such as zinc, iron, and manganese. The high phosphorus content is good for encouraging flowering, and for root development.
The product is great for repotting, transplanting, and rooting. And customers report their plants looking healthier and growing quickly after use.
Be careful with how much you use though. A small minority of people have reported it killing their plants.
The 4 fluid ounce bottle goes a long way, as you just need to use 7 drops per quart of water. And if kept in a cool, dark place with the lid tightly on, the bottle will keep for 10 years or more.
J R Peters Jack’s Classic All Purpose Plant Food
Jack’s classic plant food is good for use on all indoor and outdoor plants, including trees, shrubs, flowers, vegetables, and fruits.
It has a 20-20-20 NPK ratio. Giving it a very high amount of all the primary nutrients. Making it good for rapid growth of foliage, flowering, and the production of fruit.
It also contains many of the micronutrients that plants need including boron, copper, iron, zinc, and manganese.
The fertilizer comes in a 1.5 lb tub of powder that you mix with water before applying to your plants.
Espoma Organic Indoor Plant Food
This organic liquid fertilizer has a 2-2-2 NPK ratio. It also includes beneficial microbes to improve the health of your soil. And it contains humic acid.
It’s made from kelp extract (seaweed), bone meal, soy protein, fish protein, and poultry manure. Which means it does have a bit of a smell. But it’s not too bad once it’s diluted and goes away within a few days after use. It won’t prevent most people from using it indoors.
It’s good to use on all types of houseplants. Including ferns, palms, ivy, flowering plants, corn plant, and bamboo.
Struggling indoor plants perk up within days of being fed with this. And customers report an increase in leaf growth and greening.
The liquid comes in an 8 fluid ounce bottle. And you mix the concentrate with water before drenching the soil around your plant.
Choosing The Best Fertilizer For Houseplants
There are many different fertilizers available on the market. With different ingredients, nutrient profiles, and plants they work best for.
How do you choose the right one for your indoor plants?
Here’s some more information to help you:
The Nutrients
On the packaging of most fertilizers, you’ll see 3 numbers together. For example, 20-20-20.
These numbers show you how much of the primary macronutrients Nitrogen (N), Phosphorus (P), and Potassium (K) are in the fertilizer. Expressed as a percentage of the total weight of the product.
So, in a 30 lbs bag of 20-20-20 fertilizer, you get 6 lbs of each of the three nutrients.
These are essential for your plant’s growth, and are needed in greater quantity than any other nutrient.
Here are some of the many functions they have:
Nitrogen:
- Needed for plant growth
- Required for your plants to look green as they play a key role in chlorophyll production (also needed to create usable energy from light)
Phosphorus:
- Helps root development
- Encourages plants to flower
Potassium:
- Encourages fruiting plants to bear fruit—increases harvest and fruit quality
- Makes plants more resistant to drought, cold, and disease
- Needed for nitrogen and phosphorus to fulfill many of their functions
Plants also require the essential secondary nutrients calcium, magnesium, and sulfur, in smaller quantities than NPK. And the micronutrients boron, zinc, molybdenum, iron, manganese, chlorine, and copper.
All of these nutrients are needed in sufficient quantities for the optimum growth and health of your houseplant.
Soil often contains enough of the secondary nutrients and micronutrients to begin with. But if you’re growing plants in containers then the nutrient content of the soil will deplete over time. So supplementing extra in a fertilizer makes sure that your plant gets as much as it needs, and corrects any deficiencies.
Different types of plants will sometimes benefit from a different fertilizer formula due to their specific demands.
For example, if you’re growing flowers then phosphorus is very useful because of its role in flower development.
Whereas plants that bear fruit need more potassium and calcium. So fertilizers for fruit trees often include these in greater quantities.
Related: The Best Fertilizer For Citrus
Synthetic vs Organic fertilizer
Fertilizers come in 2 different types, organic fertilizers and synthetic fertilizers.
Is it important which one you choose for your indoor plants?
Well, they both have pros and cons.
One of the big advantages of synthetic fertilizers is that they usually contain large amounts of primary nutrients. And because they’re water soluble your plants can absorb them quickly and easily. Leading to fast and impressive growth.
But, there can be a drawback to this as well:
If you’re not careful, high levels of nutrients can overwhelm your plant and cause nutrient burn.
This is much less likely to happen with organic fertilizers. To start with, they have a lower amount of NPK.
And the nutrients are released gradually into the soil as the organic material slowly breaks down.
This organic material provides fuel for soil microbes. Helping them to thrive and produce a biologically active soil with better texture, aeration, and drainage.
This is a healthy soil for plants to grow in. By using organic fertilizer you build your soil so it’s good for the long term.
Another advantage of organic fertilizers is that they often come with helpful bacteria and fungi included that help increase the quality of your soil.
In summary:
Synthetic fertilizers are a fast and economical way of getting good results.
But if you want to build healthy soil for the long term, with less risk of damaging your plants then get an organic fertilizer.
Types Of Fertilizer
When looking at the options for houseplants you’ll see fertilizers coming in a few different forms: liquid, granular, and spikes.
Liquid fertilizers are fast-acting as they are quickly taken up by the roots. But you usually have to apply them regularly. Most of the time, liquid fertilizers are synthetic. They are easier to use than the other types as a fertilizer for indoor plants in water.
Granules (or pellets) often release nutrients slowly. Leading to gradual and continuous fertilization over a longer period of time. You can get both synthetic and organic fertilizers as granules. If they’re synthetic, they often have slow-release nitrogen in their formula to enable them to fertilize your potted plants for longer.
Fertilizer spikes are small sticks of dried fertilizer that you hammer or push into the soil. They release their nutrients gradually over time as they dissolve. You can get both organic and synthetic fertilizer spikes for plant care.
Conclusion
Using a good fertilizer will help to keep your indoor plants healthy and encourage vigorous growth of leaves and flowers.
In our opinion, the best fertilizer for houseplants is Miracle-Gro All Purpose Plant Food. It produces consistent and fast results, at an economical price.
And if you want to go organic, we recommend Jobe’s Organics All Purpose Fertilizer Spikes.
