2024’s Best Fertilizers for Indoor Plants, Tested and Reviewed
Hello, my friend, hello again; today we come together to talk about 2024’s Best Fertilizers for Indoor Plants, Tested and Reviewed and hope the blog can help you.
Help your houseplants thrive by feeding them the best fertilizer for indoor plants.
Plants get nearly all the sustenance they need from water and sunlight, but since houseplants live in containers, they do not receive the essential nutrients they need to remain strong, healthy, and pest-free. Fertilizers act as a nutritional supplement, providing houseplants with a combination of micronutrients and macronutrients that allow them to thrive.
After researching dozens of the most popular fertilizers for indoor plants, we gathered nine of the top performers. Then we tested them for a month on our own potted plants to learn more about their effectiveness for different plants, soils, and growing environments. Our top recommendation is the Espoma Organic Indoor Plant Food, which comes in a convenient and sturdy bottle allowing for simple application with impressive results. Ahead, preview the list of all our tested products and then follow along as we showcase the best fertilizer for indoor plants.
- BEST OVERALL: Espoma Organic Indoor Plant Food
↓ Jump to Review - BEST BANG FOR THE BUCK: Miracle-Gro Water Soluble All-Purpose Plant Food
↓ Jump to Review - BEST ORGANIC: Neptune’s Harvest Fish-Seaweed Blend Fertilizer
↓ Jump to Review - BEST SLOW-RELEASE: Osmocote Outdoor & Indoor Smart-Release Plant Food
↓ Jump to Review - BEST LIQUID: Dyna-Gro Grow 7-9-5 Liquid Plant Food
↓ Jump to Review - BEST FOR CACTUS: Grow More Cactus Juice Cacti & Succulents Fertilizer
↓ Jump to Review - BEST FOR FLOWERING PLANTS: JR Peters Jack’s Classic 10-30-20 Blossom Booster
↓ Jump to Review - BEST FOR HERBS: Dr. Earth Organic Life All Purpose Fertilizer
↓ Jump to Review - BEST ALL-PURPOSE: JR Peters Jack’s Classic 20-20-20 Plant Food
↓ Jump to Review
How We Tested the Best Fertilizers for Indoor Plants
Our tests encompassed different fertilizer types such as organic and synthetic options as well as liquid concentrates, water-soluble granules, and dry-application formulas. To obtain comparable results, we set up a trial with nine groups of five houseplants each. All of the plants were healthy and growing in 6-inch pots. Seven of the groups were made up of common foliage plants like pothos, dracaena, snake plant, and croton, and two specialty groups featured cacti and succulents in addition to flowering houseplants.
We tested these fertilizers from early February through early March, starting as the plants completed a semi-dormant phase. We repotted the plants into fresh potting soils that had no added plant food. After a week of acclimatization in the new soil, we began the recommended fertilization programs as directed on each fertilizer label.
Throughout testing, we monitored for any changes in plant health and vigor, foliage color, new growth, and infestation by insects or diseases. In addition to these measurements of product effectiveness, we also compared the up-front costs of the products along with the application rates, storage, mixing, and user convenience to get a clearer picture of the overall value. Finally, we recorded our observations, scored each product on a scoring rubric, and then gave the following awards to each product based on performance.
| Testing Stats | |
| Products tested | 9 |
| Time spent testing | 4 weeks |
| Tests performed | 4 to 5 |
| Price range | $10 to $20 |
Our Top Picks
We tested the best indoor plant fertilizers for a range of specific houseplant needs. If you’re looking for the best plant food for your indoor home garden, check out these reviews.
Best Overall
Espoma Organic Indoor Plant Food
Photo: amazon.com
Our Ratings: Ease of Use 4.5/5; Odor 5/5; Effectiveness 4/5; Value 4.5/5
Product Specs
- Type: Organic liquid concentrate
- Size: 8 ounces
- NPK: 2-2-2
What We Like
- Balanced NPK in a concentrated liquid formula that’s easy to mix and apply
- Organic fertilizer includes humic acid and beneficial microbes to maximize plant health
- Compact size and sturdy bottle make it easy to handle and store
- Budget-friendly; one of the most affordable organic fertilizers available
What We Don’t Like
- 8-ounce size is less economical for big plant collections; larger sizes are not available
- Requires frequent applications for best results
In our test, the Espoma organic indoor houseplant food proved effective and easy to use. The small size and sturdy bottle made it easy to work with and simple to store. The mild formula did not deliver a fast burst of growth, but after two applications within a month, the plants grew out healthy and attractive, with no noticeable insect or disease issues.
It’s worth noting that the fertilizer’s smell was notably less pungent than other organic fertilizers we’ve tested, and the odor did not persist long after application. As a concentrated liquid plant food, we had to mix the product with water. The instructions conveniently referenced filling the cap “halfway” as a measuring tool, but the cap did not have a reference line to show the exact measurement. So we estimated about 2 teaspoons worth in the cap, and it worked out just fine.
While buyers may be able to take advantage of periodic sale prices, even at the base price we were pleased to note that it was the most affordable organic houseplant fertilizer we tested in terms of both the purchase price and cost per application. The natural plant food ingredients and added beneficial microbes are proven to enhance nutrient absorption and minimize waste when used as directed.
Read our full review: Espoma Organic Indoor Plant Food
Get the Espoma fertilizer for indoor plants at Amazon, Ace Hardware, or Target.
Best Bang for the Buck
Miracle-Gro Water Soluble All-Purpose Plant Food
Photo: amazon.com
Our Ratings: Ease of Use 4.5/5; Odor 5/5; Effectiveness 4/5; Value 4.5/5
Product Specs
- Type: Water-soluble granules
- Size: 0.5, 3, 5, 5.5, 6.25, and 10 pounds
- NPK: 24-8-16
What We Like
- General purpose 24-8-16 formula promotes growth and overall plant health
- One 8-ounce package can fertilize houseplants for a whole season
- Works for both houseplants and outdoor garden plants
- Lowest purchase price and the lowest cost per application of all the fertilizers we tested
What We Don’t Like
- The low phosphorus ratio is not ideal for flowering plants
- Highly concentrated formula may contribute to nutrient pollution if not applied correctly
Miracle-Gro has been around for generations, and our test results show the reason why. It was easy to use, easy to store, produced zero smell, delivered fast results, and was the least expensive of all the fertilizers tested on a per-application basis.
Sustainability can be a complicated discussion when it comes to fertilizer, but the makers of this chemical-based plant food made a good effort. The highly concentrated fertilizer granules were vacuum sealed inside a plastic bag packed in a recyclable cardboard box. Minimal packaging paired with a high fertilizer density makes for an efficient system that generates less plastic waste over time than any of the organic fertilizers, packed in plastic bags and jugs, that we tested.
To mix up a batch, we used the included measuring scoop to add the granules to the watering can first, and then added water. The granules instantly dissolved without clumping, and no stirring was necessary. The solution gave off no smell. We swept up the few spilled granules and returned them to the package.
We fed our plants twice with Miracle-Gro—the first time a week after repotting and the second time 2 weeks later. We liked alternating plant food applications with plain water between feedings to prevent buildup of plant food residue in the soil. The plants responded well. They all sent out a flush of fresh new growth that began about 2 days after the first treatment. By the end of the test month, the new growth was beginning to harden off and the plants looked great.
Our only concern with this fertilizer, which we could not test with the time or equipment we had available, was the potential for nutrient runoff. This occurs when unused, water-soluble nutrients flow out of the soil with later watering, which not only wastes nutrients but can subsequently contribute to pollution. Excess nitrogen and phosphorus from private septic systems and municipal sewage treatment facilities can contaminate groundwater and cause unchecked algae growth in streams, lakes, and rivers. Users are advised to capture and reuse houseplant drain water, thereby reducing the risk of nutrient runoff.
This product is highly concentrated, so we used caution to only soak the soil—but not to the point of runoff—when feeding. But any unused plant food would have been flushed out the following week when we heavily applied plain water. Even with careful fertilizing and watering, it’s best to save drain water when using this and other water-soluble fertilizers.
Get the Miracle-Gro fertilizer for indoor plants at Amazon, Lowe’s, Ace Hardware, The Home Depot, or Walmart.
Best Organic
Neptune’s Harvest Fish-Seaweed Blend Fertilizer
Photo: amazon.com
Our Ratings: Ease of Use 4.5/5; Odor 3/5; Effectiveness 4/5; Value 4/5
Product Specs
- Type: Liquid
- Size: 18 ounces, 36 ounces, 1 gallon, and 5 gallons
- NPK: 2-3-1
What We Like
- A short list of minimally processed natural plant food ingredients
- OMRI listed for use in organic gardening and farming systems
- Concentrated liquid formula is easy to mix and easy to apply
- Generous phosphorus content is ideal for stimulating root and flower production
What We Don’t Like
- Strong fish smell lingers around recently fed plants for about a day
- Does not include a measuring cup or spoon for mixing the solution
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 OMRI, so users can rest assured that it’s made exclusively with natural and organic ingredients.
We loved the results from Neptune’s Harvest fish and seaweed fertilizer, but the smell could be overwhelming. We mixed the concentrate with water according to the label instructions and fed our plants every 2 weeks. The results after our month-long test were excellent: lush new growth and no symptoms of overfertilization or infestation.
One detail we found lacking in this product was a measuring device. Although we discovered that one capful approximates the required tablespoon per gallon of water, measuring with the cap was messy. Unlike the purpose-designed cap of the Espoma product above, this is just a regular cap. It needed to be thoroughly cleaned after measuring, or else the bottle would become a smelly mess.
And the smell is acute, especially in its undiluted state. It is not horrible like rotten fish but just an intense fish smell that lingers for a day or so after feeding. In a poorly ventilated space, it may not be ideal. But the nutrient analysis is just right for stimulating root and bud development, so this could be an excellent choice for cultivating seedlings, reducing transplant shock, and boosting flowering plants.
Get the Neptune’s Harvest fertilizer for indoor plants at Amazon, Gardener’s Supply Company, or Burpee.
Best Slow-Release
Osmocote Outdoor & Indoor Smart-Release Plant Food
Photo: amazon.com
Our Ratings: Ease of Use 5/5; Odor 5/5; Effectiveness 4/5; Value 5/5
Product Specs
- Type: Slow-release pellets
- Size: 1, 2, 4.5, and 8 pounds
- NPK: 15-9-12
What We Like
- Continuously feeds potted plants or garden beds for up to 6 months
- Available in 4 different sizes for smaller or larger gardens
- Outstanding value because of the fertilizer value and labor savings
What We Don’t Like
- Difficult to measure the right amount accurately for pots less than 1 quart (less than 6-inch diameter)
We anticipated some difficulty gauging the effectiveness of a slow-release fertilizer, but we were pleasantly surprised. In addition to being extremely easy to apply, the Osmocote fertilizer also delivered noticeable results within our testing time frame.
We used the included measuring scoop to apply the fertilizer pellets on the soil surface in each pot. To reduce the chance of the loose pellets washing, blowing, or falling out, we gently drilled them into the soil surface with a chopstick. (An easier method would have been to mix the fertilizer with the potting soil at repotting time.) After that, we simply watered as needed, which was about once a week.
The test plants perked up and began adding new growth right on schedule. Within a month they had a nice new flush of foliage maturing. Everything about them looked strong and healthy. The best part was that we didn’t need to mix up fertilizer or follow a weekly or biweekly routine throughout the growing season.
Although the purchase price was slightly higher than some of the other fertilizers we used, Osmocote’s value shines through in the season-long feeding that it provides. It worked out to be one of the least expensive options on a cost-per-application basis (approximately $.32 per application for 2 gallons of soil), and it eliminated the hassle of mixing solutions and keeping up with a feeding schedule. Twice a year would suffice.
Get the Osmocote fertilizer for indoor plants at Amazon, Lowe’s, Ace Hardware, The Home Depot, or Walmart.
Best Liquid
Dyna-Gro Grow 7-9-5 Liquid Plant Food
Photo: amazon.com
Our Ratings: Ease of Use 4/5; Odor 5/5; Effectiveness 4/5; Value 4/5
Product Specs
- Type: Water-soluble
- Size: 8 ounces, 32 ounces, and 1 gallon
- NPK: 7-9-5
What We Like
- Balanced nutrient formula is perfect for flowering plants and foliage plants
- Ultraconcentrated liquid is a budget-friendly choice for feeding large plant collections
- In addition to potted plants, this product can be used in hydroponics and outdoor gardens