The Best Fertilizer for Indoor Plants of 2022

Help your houseplants thrive by feeding them the best fertilizer for indoor plants.

By Savannah Sher | Updated Jun 24, 2022 5:31 PM

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We reviewed a wide range of options for this list of top picks.

Plants get nearly all the sustenance they need from water and sunlight, but since houseplants are no longer in a natural environment, they may not receive some of the plant food and nutrients they need to truly thrive. Fertilizers act as a nutritional supplement, providing houseplants with a combination of micronutrients and macronutrients that help them grow faster.

With so many fertilizers available, it can be difficult for shoppers to narrow down their options. These recommendations for the best fertilizer for indoor plants were selected for their quality formulas, versatility, value, and ease of use. Keep reading to learn about the key features to consider when shopping, and then explore the picks for the best plant fertilizer products on today’s market.

  1. BEST OVERALL: Espoma Company INPF8 Organic Indoor Plant Food
  2. BEST BANG FOR THE BUCK: Miracle-Gro Water Soluble All Purpose Plant Food
  3. BEST ORGANIC: Neptune’s Harvest Fish & Seaweed Fertilizer
  4. BEST SLOW-RELEASE: Osmocote Smart-Release Plant Food
  5.  BEST GRANULAR: Jobe’s Organics All Purpose Plant Food
  6. BEST LIQUID: Dyna-Gro 719000 Grow 1 qt Plant Food
  7. BEST FOR CACTUS: Grow More 3130 16 Oz Cactus Juice 1-7-6
  8. BEST FOR FLOWERING PLANTS: J R Peters 10-30-20 Blossom Booster Fertilizer
  9. BEST FOR HERBS AND VEGGIES: Dr. Earth Organic and Natural All Purpose Fertilizer
  10. BEST BALANCED: Jack’s Classic All Purpose 20-20-20 Plant Food

Types of Fertilizer for Indoor Plants

The three primary types of houseplant fertilizer are liquid, granular, and slow-release pellets. Each kind has both advantages and disadvantages.

Liquid

Before applying it to a plant’s leaves or soil, a liquid fertilizer must be mixed with water, which requires some additional measuring. However, the water makes it easier to apply sparingly and avoid overfertilization. This type typically is best for those with many houseplants, because a large amount of water must be used to dilute very little fertilizer.

However, liquid fertilizers must be applied frequently—every 1 to 2 weeks.

Granular

Granular fertilizers are affordable and effective. Simply sprinkle the fertilizer on top of the soil, then mix or water it in. However, this application method is not very precise, which may lead to overfertilization.

Use a granular fertilizer when initially planting or repotting a plant so it can be thoroughly mixed into the soil. It typically must be reapplied after 4 to 6 weeks.

Slow Release

Slow-release fertilizers come in several formats, including pellets, spikes, pods, and capsules. Because they emit nutrients gradually, they can last from 3 to 6 months. They’re typically only available in traditional—not organic—formulas. Only experienced plant owners who are familiar with the level of fertilizer their particular plants require should use it.

What to Consider When Choosing the Best Fertilizer for Indoor Plants

While it’s easy to assume that all indoor plant fertilizers offer similar performance, a number of factors affect their functionality. Keep reading to learn about several of the most important features to consider when choosing the best houseplant fertilizer.

NPK Ratio and Plant Species

The best plant fertilizers contain a mixture of macronutrients—usually nitrogen (N), phosphorus (P), and potassium (K)—along with micronutrients. The balance of these three macronutrients is represented by its NPK ratio, which should be listed on the fertilizer’s packaging. For example, an NPK ratio of 10-10-10 means that a fertilizer includes 10 percent nitrogen, 10 percent phosphorus, and 10 percent potassium. The higher the percentage of nutrients, the more potent the fertilizer.

Because each plant species has different nutritional needs, a “perfect” NPK ratio doesn’t exist. Generally, green houseplants require a balanced NPK ratio or one that’s slightly higher in nitrogen. A higher balance of phosphorus is particularly beneficial for flowering plants such as African violets, oxalis, and peace lilies. Phosphorus also aids in fruit production, making it beneficial to edible plants.

Organic or Traditional

One of the primary decisions shoppers must make is choosing between a traditional or an organic fertilizer.

  • Organic fertilizers are made entirely from natural ingredients. Although they’re free of potentially harmful chemicals and synthetics, they aren’t quite as powerful as traditional products. Moreover, over time, their natural content can emit an unpleasant odor. Since the marketing term “organic” isn’t regulated particularly well in fertilizers, look for a product that’s been endorsed by the Organic Materials Review Institute (OMRI).
  • Traditional fertilizers contain a blend of minerals balanced for feeding houseplants. Typically costing less than organic fertilizers, they come in more concentrated formulas.

Application

A fertilizer’s ease of application depends largely on whether it’s a liquid, granular, or slow-release formula.

  • Liquid fertilizers must be diluted with water according to the manufacturer’s instructions. Using a spray bottle, either spray it on their leaves, or pour this type of fertilizer onto the plant’s soil.
  • Granular fertilizers can be sprinkled evenly on the soil’s surface and mixed into the top 3 inches of soil before it’s watered, which releases the nutrients.
  • Slow-release fertilizers vary in application method. Follow the manufacturer’s instructions for fertilizing with pods, spikes, pellets, or capsules.
Best Fertilizer For Indoor Plants

Photo: amazon.com

Our Top Picks

After learning about houseplant fertilizers, it’s time to choose the best plant food for your indoor home garden. This list features the best indoor plant fertilizers and covers a range of specific houseplant needs.

Best Overall

Best Fertilizer For Indoor Option: Plants_Espoma Company INPF8 Organic Indoor Plant Food
Photo: amazon.com

Espoma’s organic indoor plant food has an NPK ratio of 2-2-2, which means that it features a balanced mixture of macronutrients to benefit a wide variety of houseplants. It’s made with natural ingredients, making it a perfect choice for organic gardening. Since the macronutrient percentages are relatively low, this product is an excellent pick for beginners who tend to overfertilize plants.

To use this Espoma product, mix 2 teaspoons of the liquid fertilizer with 1 quart of water, then thoroughly saturate the plant’s soil. According to the manufacturer, it should be applied every 2 to 4 weeks.

Product Specs

  • Type: Liquid
  • Size: 8 ounces
  • NPK: 2-2-2

Pros

  • Well-balanced 2-2-2 formula
  • Suitable for all houseplants
  • Affordable price

Cons

  • Only one size bag available

Get the Espoma Organic Indoor Plant Food on Amazon or at Ace Hardware.

Best Bang For The Buck

The Best Plant Food Option: Miracle-Gro Water Soluble All Purpose Plant Food
Photo: amazon.com

This Miracle-Gro indoor plant food has a unique granular formula designed to be mixed with water for more even application. During a plant’s active growth period, apply this fertilizer every 1 to 2 weeks.

This formula has an NPK ratio of 24-8-16, which means a high nitrogen content, so it’s an excellent all-around pick for green houseplants but may not be the best choice for flowering plants since it’s low in phosphorus.

While this small 8-ounce bag should be sufficient to fertilize houseplants over one season, larger sizes are available.

Product Specs

  • Type: Water-soluble granules
  • Size: 0.5 pounds
  • NPK: 24-8-16

Pros

  • 24-8-16 formula that’s ideal for non-flowering plants
  • Can be used indoors and outdoors
  • Affordable price

Cons

  • Not ideal for flowering plants

Best Organic

Best Fertilizer For Indoor Plants Option: Neptune’s Harvest Fish & Seaweed Fertilizer
Photo: amazon.com

This organic fertilizer from Neptune’s Harvest is formulated with a combination of fresh fish and seaweed from the North Atlantic. It’s certified by the OMRI, so users can rest assured that it’s made exclusively with natural and organic ingredients.

For houseplants, the manufacturer recommends mixing a tablespoon of the liquid formula into a gallon of water before thoroughly saturating the plant’s soil. For best results, it should be reapplied every 1 to 2 weeks. With an NPK ratio of 2-3-1, it contains a high percentage of phosphorus, ideal for flowering plants. Since its macronutrient content is relatively low, even novice users are unlikely to inadvertently overfertilize their plants.

Product Specs

  • Type: Liquid
  • Size: 18 ounces
  • NPK: 2-3-1

Pros

  • Multiple sizes available
  • Certified organic by the OMRI
  • Ideal for flowering plants

Cons

  • May have an unpleasant smell

Best Slow-Release

Best Fertilizer For Indoor Plants Option: Osmocote Smart-Release Plant Food
Photo: amazon.com

The granules of this smart-release plant food from Osmocote are coated with a semipermeable resin shell that releases nutrients slowly based on temperature, ensuring that your houseplants receive the supplements they need during their active growing periods. The pellets can be applied only every 6 months; however, its slow-release formula means some plants may receive more nutrients than they need.

The 8-pound bag will last for a long time if users feed only indoor plants, and it’s resealable to keep the formula from drying out.

Product Specs

  • Type: Slow-release pellets
  • Size: 8 pounds
  • NPK: 15-9-12

Pros

  • Works for up to 6 months
  • Multiple sizes available
  • Excellent value for the quantity

Cons

  • Users risk overfertilizing

Best Granular

Best Fertilizer For Indoor Plants Jobe’s Organics All Purpose Fertilizer
Photo: acehardware.com

This granular, completely biodegradable fertilizer from Jobe’s Organics helps contribute to a healthy ecosystem by omitting synthetic chemicals. Due to its all-purpose 4-4-4 NPK ratio, this fertilizer works on all types of houseplants as well as herbs, vegetables, and outdoor flowers. The formula contains the proprietary microorganism archaea, which makes the fertilizer act quickly by breaking down the materials in the plant’s soil.

Apply the fertilizer when planting or repotting and then again at 4- to 8-week intervals. The 4-pound bag is resealable to help keep the fertilizer fresh.

Product Specs

  • Type: Granular
  • Size: 4 pounds
  • NPK: 4-4-4

Pros

  • Well-balanced 4-4-4 formula
  • OMRI listed
  • Perfect for all-purpose use
  • Multiple sizes available

Cons

  • Difficult to apply precisely

Best Liquid

Best Fertilizer For Indoor Plants Option: Dyna-Gro 719000 Grow 1 qt Plant Food
Photo: amazon.com

This fertilizer from Dyna-Gro is extremely concentrated, requiring only ¼ to ½ teaspoon of the fertilizer to a gallon of water.

With a 7-9-5 NPK ratio, this formula is high in nitrogen and phosphorus, suitable for fostering growth in flowering plants, but it also works well as an all-purpose pick. In fact, it’s marketed as suitable for indoor and outdoor plants as well as for lawn care and ornamental flowers.

Product Specs

  • Type: Water soluble
  • Size: 32 ounces
  • NPK: 7-9-5

Pros

  • Perfect for flowering plants
  • Ultra-concentrated formula
  • Versatile

Cons

  • Only one size available

Best For Cactus

Best Fertilizer For Outdoor Plants Option: Grow More 3130 16 Oz Cactus Juice 1-7-6
Photo: walmart.com

Cacti and succulents have unique nutritional needs and thus require an NPK ratio different from other houseplants. Featuring a low quantity of nitrogen and higher levels of phosphorus and potassium and a macronutrient balance of 1-7-6, Cactus Juice Fertilizer is crafted specifically to cater to those needs. It also includes calcium, an additional benefit for cacti and other drought-resistant plants.

To use, mix 1 teaspoon of plant food with a gallon of water and apply it to the cactus’s soil. Since it’s a liquid formula, reapply it every 1 to 2 weeks during the growing season.

Product Specs

  • Type: Liquid
  • Size: 16 ounces
  • NPK: 1-7-6

Pros

  • Specially formulated for cacti and succulents
  • Excellent value
  • Includes calcium

Cons

  • Must be applied frequently

Best For Flowering Plants

Best Fertilizer For Indoor Plants Option: J R Peters 10-30-20 Blossom Booster Fertilizer
Photo: amazon.com

Growing flowering plants indoors can be tricky, and one reason that a plant isn’t producing flowers can be that it lacks phosphorus. This Jack’s Classic fertilizer, with a 10-30-20 NPK ratio, is patently designed to increase the number of blooms on flowering plants and ensure that their petals are bright and vibrant. It’s equally proficient at feeding indoor and outdoor plants, including fruits and vegetables.

Add ½ teaspoon of the water-soluble formula to a gallon of water for the ideal mixture. Reapply every 2 weeks for the best results.

Product Specs

  • Type: Water-soluble granules
  • Size: 1.5 pounds
  • NPK: 10-30-20

Pros

  • 10-30-20 is perfect for flowering plants
  • Suitable for vegetables and fruit
  • Feeds through both roots and leaves

Cons

  • Risk of overfertilizing

Best For Herbs And Veggies

Best Fertilizer For Indoor Plants Option: Dr. Earth Organic and Natural All Purpose Fertilizer
Photo: drearth.com

Growing herbs, vegetables, and fruit year-round indoors is nearly impossible. Luckily, many varieties can thrive inside as long as they receive the right nutritional supplements. This all-purpose fertilizer from Dr. Earth is perfect for growing edible plants indoors because of its complex formulation. It’s also easy to use because it doesn’t need to be mixed into the plant’s soil. However, for new plantings, mix the granules into the topsoil if possible.

While many slow-release formulas use traditional synthetic ingredients, this fertilizer is organic yet still feeds plants for several months at a time. However, for indoor potted plants, the manufacturer recommends reapplying the fertilizer monthly to make up for the lack of nutrients in potting soil.

Product Specs

  • Type: Slow release
  • Size: 1 pound
  • NPK: 4-6-5

Pros

  • Organic ingredients
  • Easy to apply
  • Many sizes available

Cons

  • Must be applied more frequently to indoor plants

Best Balanced

Best Fertilizer For Indoor Plants Option: Jack’s Classic All Purpose 20-20-20 Plant Food
Photo: amazon.com

A 1-1-1 ratio of nitrogen, phosphorus, and potassium is generally recognized as the most flexible option for plant fertilizers. This one from Jack’s Classic has an NPK ratio of 20-20-20, offering a high concentration of all three micronutrients. This balance is particularly useful for green foliage plants. Mix ½ teaspoon of the granules into a gallon of water and apply it every 2 weeks.

This versatile formula works as well on indoor houseplants as it does on shrubs, trees, herbs, flowering ornamental plants, evergreens, and perennials.

Product Specs

  • Type: Water-soluble granules
  • Size: 1.5 pounds
  • NPK: 20-20-20

Pros

  • Well-balanced 20-20-20 formula
  • Good for all-purpose use
  • Affordable price

Cons

  • Only one size available

Our Verdict

After reviewing this guide, you now know more about shopping for fertilizer for your indoor plants. We recommend the Espoma Company Organic Indoor Plant Food for its versatility, well-balanced NPK ratio, and relatively affordable price. Those on a budget may appreciate the Miracle-Gro Water Soluble All Purpose Plant Food, which offers similar performance at a lower price point.

How We Chose the Best Fertilizer for Indoor Plants

Years of experience covering home and garden products as well as extensive product research went into creating this guide. We explored more than 40 fertilizer options and weighed a number of practical considerations before making our recommendations.

  • Nutrient mix: We aimed to include fertilizers with a variety of micronutrients and macronutrients and feature options with a variety of NPK blends for different types of houseplants.
  • Type: Many different kinds of plant fertilizer are on the market, and we tried to showcase the breadth of options available by including both organic and traditional options as well as a variety of formula types.
  • Value: Fertilizers vary widely in quantity and concentration, but we considered overall value for the cost when making our recommendations.

Tips for Using the Best Fertilizer for Indoor Plants

The following tips help ensure your plants thrive without risking overfertilization.

  • Since all fertilizers are different, follow the instructions on the manufacturer’s label.
  • Avoid overfertilization—reduce your fertilizing schedule if your plant’s leaves droop or begin to look burnt at the edges.
  • Know how to recognize nutritional deficiency based on leaf color: Browning leaves lack potassium, yellow leaves indicate a nitrogen deficiency, and purple leaves often mean the plant lacks phosphorus.
  • There’s no need to fertilize most houseplants during their dormant season if you live in an area that experiences standard seasonal temperature changes.

FAQs

While you now know more about choosing the best plant fertilizer, you might still want more information about how to use it. Here are some answers to some of the most frequently asked questions about fertilizing indoor plants.

Q. Why do indoor plants need fertilizer?

Houseplants have been removed from their natural habitat and are therefore lacking the macronutrients and micronutrients present in their native soil that helps them remain healthy. Fertilizers supplement these nutrients.

Q. What’s in houseplant fertilizer?

Houseplant fertilizers contain a mixture of macronutrients (nitrogen, phosphorus, and potassium) and micronutrients that supplement the nutrients already in the plant’s soil.

Q. How do I fertilize indoor plants?

The fertilization method depends on the chosen formula. Add powder and granular fertilizers to the plant’s soil, then water. Dilute liquid fertilizers with water before application.

Q. How often should I fertilize indoor houseplants?

The ideal fertilization schedule depends on the type of fertilizer you choose. Liquid fertilizer should be applied every 2 to 4 weeks, whereas a granular fertilizer only needs to be applied every 4 to 6 weeks. Fertilize with a slow-release formula every 3 to 6 months.

Q. Can you overfertilize houseplants?

Overfertilization is a common problem with houseplants. The signs of overfertilization vary depending on the plant species, but they include symptoms like wilting, burnt leaves, and dried leaf margins.

Q. When should I fertilize indoor plants?

Indoor plants typically don’t need fertilizing during their dormant season, which usually takes place over the winter. Start fertilizing your houseplants in early spring, about 8 weeks before the last expected frost. In areas that don’t experience winter frosts, reduce applications to half-strength.