7 Best Indoor Plant Fertilizer Reviews and Buying Guide

Fertilizers act as a supplement for indoor gardens’ growing process. While plants acquire natural energy from photosynthesis, fertilizers improve this process.

Choosing the best indoor plant fertilizer helps you enhance plant fertility, from growing strong roots, lush leaves to producing fruitful edibles.

Our research on the wide range of products on the market concludes that the Miracle-Gro B0019QEB86 Indoor Plant Food Spikes is the premium choice.

Miracle stands out on the market as a natural product that works well on various plant types, including edible produce. This slow-release fertilizer provides essential nutrients for healthy growth. Moreover, these benefits come at a notably low price.

This article will guide you through the top products along with their benefits and limitations.

Buying guide for indoor plant fertilizer

Types of indoor plant fertilizers

Granular

When applied, the dry granular form creates a barrier to provide nutrients and protect the soil. If the barrier is preserved correctly, the residual effect can last for years.

Most manufacturers’ instructed volume may turn out to be underfeeding or overfeeding the plants on the flip side. In the first few applications, you will need to observe the conditions to adjust the volume accordingly until you find the right option.

Beginners in gardening have the common mistake of leaving excess granules on the surface. This practice will backfire by building up mineral salts, which results in decreasing the soil quality.

Liquid

Liquid fertilizers have a fast-acting formula that penetrates the soil to spread nutrients evenly to the roots. Thanks to this feature, you only need to apply this fertilizer type once or twice a month.

Using a concentrated solution, you can withdraw a sufficient fertilizer ratio to the spray bottle, then water it down and start spraying on the roots.

This practice is excellent for controlling the dosage, and the diluted fertilizer helps plants absorb nutrients better.

On the flip side, unused liquid fertilizers tend to evaporate. Make sure you seal the container tight and store it in a cool area away from direct sunlight.

Slow-release fertilizer

Slow-release fertilizers score high on the market because they come in various forms. The category includes spikes, seeds, and pellets.

This product requires a single application by injecting the spikes into the ground. The spikes will gradually release nutrients over time, with the duration from 2 months up to 6 months.

If you have small indoor plant pots, slow-release fertilizer is the ideal option. It provides easier volume control and flexible use.

However, one minus point is the slow-release fertilizers need frequent refills for large gardens.

Essential ingredients

A high-quality indoor plant fertilizer contains macronutrients and micronutrients. Natural fertilizers provide a sufficient amount of nutritious values and better protection than synthesized chemicals.

The 3 essential macronutrients include:

  • Nitrogen (N): Supports the foliage growth.
  • Phosphorus (P): Enhances the flowers to grow bigger and have vibrant colors.
  • Potassium (K): Focus on growing a strong root system.

These macronutrients are often displayed as N-P-K on fertilizer packaging to show their ratio.

For example, the N-P-K ratio of 10-10-10 means the nitrogen volume is equal to phosphorus and potassium. Another N-P-K ratio of 20-5-5 shows that the nitrogen is 4 times higher than phosphorus, and the phosphorus is equal to potassium.

This ratio helps gardeners decide on the right house plant fertilizer. Slow-release fertilizers have many eco-friendly options, while liquid or granular fertilizers have a wide range of products from natural to chemical components.

Depending on the plant type, specialty fertilizers also have additional nutrients.

A proportion of magnesium and boron support tremendously in encouraging plant growth. Other formulas include using a combination of nitrogen and sulfur.

Healthy volume

Although manufacturers include instructions on the box, certain species need a customized volume of fertilizer. However, you can’t customize all types of fertilizers as the formula can harm the plants.

Chemical components require higher cautions than organic fertilizers. Start by using the fertilizer with the lowest chemical level and observe the results. Immediately stop applying the volume when you see brown spots or yellow leaves.

Safety level

Most indoor plant fertilizers are odorless and safe upon contact with human skin. For gardeners with sensitive skin, a pair of gloves guarantee full protection.

The next factor to consider is the plant itself. Lemons, kumquats, and peach trees are examples of fruit trees you can grow indoors. When buying fertilizers, it is better to choose an all-natural formula for edible produce.

Watch the video to learn how to fertilize indoor plants:

Top 7 Indoor Plant Fertilizers Reviews

Miracle-Gro B0019QEB86 Indoor Plant Food Spikes – Best Overall

Features

  • Easy-to-use design
  • 100% organic formula
  • Treatment for various indoor species
  • Long-lasting effect
  • Affordable price

What we like

Miracle-Gro garden feeder spikes are suitable for various household plants, from flora, ferns to pathos. The eco-friendly formula is safe for preserving the soil quality, ensuring plants get enough micronutrients to grow. Plus, the organic components work well for fruits and vegetables.

The process of using Miracle-Gro includes 2 quick steps.

First, create a small hole between the plant and the pot’s rim, then inject the spike until it is covered halfway. One spike can treat average-sized potted plants for up to 2 months, while larger pots need 2 or 3 spikes for a continuous effect.

This product brings a refreshing garden atmosphere at a good value deal. However, in a temperate climate, you will need to store the spikes in a cool area because the heat can melt the fertilizer and decrease its quality.

What Can Be Improved?

  • Decreased quality in a temperate climate

Osmocote B0071CZTBA Smart-Release Plant Food Plus – Best For Growth Season

Osmocote Smart-Release Plant Food Plus Outdoor & Indoor, 1...
11,123 Reviews
Osmocote Smart-Release Plant Food Plus Outdoor & Indoor, 1...
  • Our best formula, fortified with 11 essential nutrients
  • Works with virtually all plant varieties, in all growing...
  • Feeds up to 6 full months

Features

  • Nutrients for indoor and outdoor gardens
  • Safe for common herbs
  • Treatment up to 6 months
  • Good mineral balance
  • Detailed instructions

What we like

With 11 essential nutrients, this fertilizer is ideal for treating indoor and outdoor plants, especially in the critical growth stages. Osmocote also provides nutrients to the common types of herbs.

One bottle feeds the garden for up to 6 months and only requires you to apply once every 2 or 3 weeks.

Each purchase comes with a scoop to help measure the exact volume. In the dry season, simply add water, and the granules will blend in the soil without building up mineral salts.

The manufacturer includes the correct dosage instructions, which guarantee no-burn or harmful results when the correct dosage is applied.

The downside is you can’t customize the dosage for different species because the ingredients contain a high chemical level.

What Can Be Improved?

  • Potent chemical ingredients

Earthworm Technologies EarthPods B01CPSZLVC Premium Indoor Plant Food – Best For Soil Health

EarthPods Premium Indoor Plant Food – Easy Organic...
1,162 Reviews
EarthPods Premium Indoor Plant Food – Easy Organic...
  • CONCENTRATED PREMIUM ALL PURPOSE ORGANIC PLANT FOOD —...
  • NO MESSY LIQUIDS / NO CONFUSING MEASURING SPOONS / NO STINKY...
  • SO FAST & EASY TO APPLY — Push 1 EarthPod all the way into...

Features

  • All-natural ingredients
  • Eco-friendly packaging
  • Supplements to enrich the soil
  • Compact design for easy storage
  • Solution for a complete plant development
  • Impressively long-lasting usage

What we like

EarthPods is a well-known brand for its concentrated organic plant food. The capsule is designed to enhance healthy growth, from stimulating the strong plant roots to improving vibrant leaves.

The residual effect provides rich soil to protect the garden from diseases in the long run. 1 capsule contains a significant volume of odorless fertilizer to feed the garden for up to 5 years.

This product is easy to use. Push the capsule in the soil, then add water to help release minerals directly to the roots, which is the critical part of the plants. This quick and easy step requires no cleanup.

When the minerals run out, the remaining parts will dissolve in the soil and enrich it in the process. Earthworm ensures eco-friendly packaging, and it is also recyclable.

On the flip side, the formula causes succulents to wither.

What Can Be Improved?

  • Harmful for succulents

Easy Peasy Plants B07XGDDJ6C Liquid Indoor Plant Food – Best For Flowering, Tropical Plants

Liquid Indoor Plant Food, All-Purpose Indoor Plant...
1,344 Reviews
Liquid Indoor Plant Food, All-Purpose Indoor Plant...
  • Promotes Healthy Green Leaf Growth and Colorful Blooms
  • High Concentrate reduces plastic bottle use by 50% compared...
  • Develops a strong root system promoting healthier plants

Features

  • Fast-acting formula
  • Treatment for flora and succulents
  • Protection from diseases and insects
  • The customized ingredient list for vibrant leaves and blooms
  • Excellent cost-efficiency

What we like

With this organic liquid fertilizer, your indoor garden will have fast development and maintain strong health to withstand diseases and insects. The ingredient list is created explicitly for indoor gardens with sulfur as the secondary macronutrient.

Easy Peasy requires a small quantity for the best performance. Only 1/2 teaspoon of fertilizer for two cups of water is sufficient to boost green leaves and beautiful flowers. This feature saves costs on supplies for a long duration.

The formula is fast-acting, showing easily noticeable results after 2 months. Another plus point is Easy Peasy is the best plant food for tropical species and even succulents.

Aside from these advantages, this indoor plant food’s drawback is the fragile bottle that breaks easily during the shipping process. You will have to secure the leaking item upon receiving the package.

What Could Be Improved?

  • Loosen bottle cap during shipment

Jobe’s B000279304 Fertilizer Spikes For All Indoor Houseplants – Best For Root Development

Features

  • Odorless formula
  • Safe on contact with human skin
  • No watering required
  • Supplements for nutrient absorbing process
  • Long-lasting supply of 50 spikes

What we like

Jobe’s spikes are pre-measured with the precise amount of fertilizer for healthy growth. Once injected near the roots, the odorless formula starts working immediately, leaving fresh air for the gardener. The formula contains no chemicals, lowering the risks for skin allergies.

Each purchase comes with 50 spikes. With one spike working continuously for 8 weeks, this purchase is guaranteed to last for a long time.

Jobe differentiates itself from the other products by focusing on nourishing the roots. A strong root system enhances nutrient uptake. This process results in thriving green leaves and vibrant flowers.

Although this fertilizer provides sufficient nutrition for mature plants, the root growing process takes some time to show effects.

What Can Be Improved?

  • Slow effect for mature plants

Miracle-Gro B01BQ9WZAG Indoor Plant Food – Best For Edible Produce

Miracle-Gro 1000551 Indoor Plant Food (Liquid), 8 oz, Feeds...
474 Reviews
Miracle-Gro 1000551 Indoor Plant Food (Liquid), 8 oz, Feeds...
  • Instantly feeds all indoor houseplants
  • For all indoor plants, including edibles
  • Feeds instantly

What We Like

  • Convenient design
  • Instant effect
  • Odorless all-purpose formula
  • Treatment for fruit and vegetable garden
  • Enhancement for both young and mature growth stage

What we like

This all-purpose houseplant fertilizer has a balanced ratio of nutrients. Thanks to the handy pump, gardeners can feed the roots directly from the bottle. This feature saves time for diluting the solution.

The odorless natural formula works well on young and adult plants in different environments, including greenhouse and outdoor plants.

Moreover, Miracle-Gro nutrients focus on developing fruits. You can also use this fertilizer in the harvest season without withering the produce. Miracle-Gro only requires a weekly application for the best performance.

The only downside is this liquid plant fertilizer’s higher price than other products in the same category.

What Can Be Improved?

  • High price

Vitamin Institute SUPERthrive B000EJ0PD4 Plant Vitamin Solution – Best For Reviving Plant and Encouraging Blooms

SUPERthrive VI30155 Plant Vitamin Solution, 1 Pint,Multi
1,615 Reviews
SUPERthrive VI30155 Plant Vitamin Solution, 1 Pint,Multi
  • Superthrive Is a Highly Concentrated Non-toxic Vitamin...
  • Superthrive Replenishes the Soil to Nourish and Encourage...
  • Superthrive Maximizes Potential by Quickly Building a Strong...

Features

  • All-natural ingredients
  • Treatment for reviving plants
  • Special vitamins for flowers
  • Easy to use design
  • Soil nourishment

What we like

SUPERthrive is the best indoor plant fertilizer for reviving plants from diseases. After that, this liquid fertilizer provides essential nutrients with high nitrogen for foliage growth.

The vitamins are specifically formulated to enhance petal colors. This feature is suitable for use from spring through summer, where blooming flowers bring a lively atmosphere to your home.

SUPERthrive natural ingredients act as supplements to enrich the soil. The residual effect maintains healthy roots and leaves in the long run.

Before applying this product to the roots, gardeners need to water down the concentrated fertilizer formula. This practice helps the liquid penetrate the soil easier.

What Can Be Improved?

  • Extended time for watering down the solution

Conclusion

After a close inspection of the top 7 products, our final choice for the best indoor plant fertilizer is the Miracle-Gro B0019QEB86 Indoor Plant Food Spikes.

When buying house plant fertilizers, it is essential to choose the type that suits your purpose.

Next, consider the list of nutrients. Depending on the ratio, the nutrients focus on developing the roots, the leaves, or the flowers. Some products offer flexible use in which you can adjust the fertilizer volume.

Finally, if your garden is covered with fruitful plants, choose the fertilizer that is safe for edible produce.

Last update on 2021-04-30 / Affiliate links / Images from Amazon Product Advertising API

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