Fertilizer is basically a multivitamin for your plants.
It supplements the energy they’re getting from the sun and the soil, making sure they have everything they need to grow strong roots, lush leaves, and beautiful blooms.
If you’re looking for the best fertilizer for indoor plants, we’re here to help. There’s a lot to think about when it comes to choosing the right formula. Here are some of the main things to think about while you shop.
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What Kind of Fertilizer is Best for Indoor Plants?
There are a lot of different types of fertilizers to choose from which is one reason why it can be so tricky finding the right one for indoor plants. Here are a few different types to consider:
Liquid fertilizers are usually added to your watering can every time or every other time you water. Some formulas can be used for feeding your plants once or twice a month.
One of the best things about liquid fertilizer is you have a lot of control over how much is being applied. You can stop fertilizing during dormant periods and be confident that there isn’t any fertilizer still being released in the soil.
On the other hand, the downside is that you have to remember to add fertilizer to the water at the appropriate time which is easier said than done.
Granular fertilizers are mixed into the soil. They work especially well when you’re first potting a plant and can mix the granules throughout the pot.
Granules are a little tricky to use with indoor plants because they release all their nutrients at once when the plant is watered so it’s not easy to tell how much the plants are getting. Follow the directions on the package very carefully so you don’t over or under-feed your plant.
Slow-release fertilizers come in many forms, including spikes, pods, and capsules. They have a time-release coating that allows the nutrients to slowly make their way into the soil.
This type of fertilizer works better in small pots because you don’t have to worry about nutrient distribution as much since there’s less area to cover.
One of the downsides to slow-release fertilizers is that there’s no way of knowing how quickly the nutrients are dissolving. Ideally, the time-release shell is keeping it somewhat even but you never really know.
The 10 Best Fertilizers For Your Indoor Plants
There are a lot of options when choosing the right fertilizer for indoor plants. Here are some of the best options out there.
Indoor Plant Fertilizer Reviewed
1. Miracle-Gro 300157 Indoor Plant Food Spikes
These plant food spikes from Miracle-Gro are ideal for all indoor potted plants, including spider plants and ferns. Each spike is loaded with the micronutrients that your potted plants need and you can add more spikes as needed for larger plants.
One of the best things about this indoor plant fertilizer is how easy it is to use. All you have to do is poke a hole midway between the plant root stem and the rim of the pot. Then, push the spike into the soil until it’s covered.
Each spike works continuously for up to two months, though you should replace them every 30 days during the spring and summer when growth is more active.
2. Miracle-Gro Water Soluble All Purpose Plant Food
Miracle-Gro is one of the most well-known fertilizer brands so it’s no surprise to see another one of its products on our list. Rather than a spike, this product consists of water-soluble granules that you water into the soil.
When used as directed, this fertilizer won’t burn. It’s good for all plants, indoor and outdoor, so it’s a good choice if you have a lot of potted plants and want to give your outdoor plants some love, too.
This fertilizer should be applied once every one to two weeks for the best results. It’s full of everything your plants need to give them the instant nutrition they need to grow strong and healthy.
3. Osmocote Smart-Release Plant Food Plus Outdoor & Indoor
Another option that’s great for indoor plants is this granular formula from Osmocote. Since it’s fortified with 11 essential nutrients, this fertilizer is very effective. You can use it on almost any plant in any growing condition, indoors or outdoors.
One of the best things about this product is that it feeds your plants for a full six months so you don’t have to worry about reapplying after a few weeks. When used as directed, it won’t burn or damage your plants.
Don’t worry – application is simple. Just use the included scoop to measure the right amount of fertilizer – one scoop for every two gallons or four square feet. Mix the granules into the top three inches of soil and water regularly. That’s it!
4. EarthPods Premium Indoor Plant Food
One of the most unique indoor plant fertilizers out there is EarthPods. This fertilizer comes in easy-to-use capsules, each containing concentrated organic plant food that stimulates root and stem development, improves leaf color, and builds resistance against diseases.
One tube of this product contains 100 pre-measured pods – a five-year supply for a single houseplant. Not only is the tube easy to store, but it’s also 100% recyclable and made 100% sustainably made in the USA.
All you have to do is insert one of these pods near the center roots and water your plant. The pods break down slowly, releasing nutrients and trace minerals right to the roots. Use just one or two pods for small plants or up to eight for large ones.
5. Jobe’s Organics 09524 Purpose Granular Fertilizer
This is a great choice if you want an organic fertilizer that’s renewable, sustainable, and biodegradable. It’s certified for organic gardening and improves soil conditions to help your plants grow strong, resisting disease, drought, and insects.
Jobe’s Organics uses Biozome, a proprietary mix of fungi, healthy bacteria, and Archaea to help improve soil quality long term so your indoor plants can thrive. Either mix this in with potting soil before planting or add it to the dripline of existing plants.
This fertilizer comes in a large 16-pound bag so it’s a good choice if you’re repotting or adding new indoor plants to your collection and need a lot of fertilizer. The easy-pour bag can be resealed for safe and easy storage.
6. Schultz All Purpose Plant Food
If you prefer liquid fertilizer, take a look at this product from Schultz. Mixing this product is really easy – just add seven drops to each liter of water before regular watering. Or, you can feed your plants once or twice a month using 14 drops in a liter of water.
You can add this product when first planting, for maintenance, or when transplanting or repotting. This versatile formula is great for a variety of plants, too. Whether you’re growing an indoor herb garden or tending to orchids and cacti, this all-purpose formula is a good choice.
Each bottle in this two-pack contains eight ounces of fertilizer. Since you’re only using between seven and 14 drops at a time, this one can last a long time, depending on how many plants you have.
7. Jobes 5001T Houseplant Plant Food Spikes
Another option that’s really easy to apply is these plant food spikes from Jobes. They’re formulated for all indoor plants and provide continuous nutrition, right at the root for easy availability.
Each spike is pre-measured and formulated to be inserted directly into the soil. The size of the plant determines how many spikes you need. For example, for a four-inch pot, use two spikes. For a 12-inch pot, use six. To get the best results, reapply every eight weeks.
This double-pack comes with 50 spikes in all. That can last you a while, depending on how many plants you have. There’s no mixing or strong odor and it doesn’t leach out of the pot when you water.
8. JR Peters Jacks Classic All Purpose Fertilizer
This water-soluble fertilizer is evenly balanced to help your plants grow strong roots, stems, and leaves. Jack’s Classic uses enhanced micronutrients that are effective at any stage of plant growth.
There are two ways to use this product. You can dissolve it into the water for regular, routine care or use it as a periodic feed a few times a month. If you plan to use this fertilizer long-term over a few months, alternating with plain water is best to avoid increased nitrogen or phosphorus in the soil.
This product can be applied to the roots or used as a leaf spray. Both methods are equally effective and easy to do. Follow the included instructions for the proper proportions when mixing.
9. Aquatic Arts Indoor Plant Fertilizer
This formula from Aquatic Arts is made specifically for house plants, whether in a pot, holder, or hanger. It promotes strong, healthy growth and prevents wilting more effectively than most pellets or granules.
Just use a teaspoon of this liquid in every two cups of water to give your plant the vitamins, nitrogen, and phosphorus it needs for better root, leaf, and bloom growth. This eight-ounce bottle lasts for up to a year, depending on how many plants you have.
We really like how versatile this fertilizer is, too. You can use it on just about any indoor plant, including poinsettias, orchids, African violets, cactus, air plants, mums, and Gerbera daisies.
10. Espoma Company INPF8 Organic Indoor Plant Food
Another easy-to-use liquid fertilizer is this formula from Espoma. It’s all-natural and organic and includes beneficial microbes to deliver the best results.
One of the things we like best about this product is how easy it is to measure and mix. All you have to do is shake the bottle well then turn it upside down, making sure the lid is secure. Then, turn the bottle upright, open the lid, and your pre-measured dose is ready to use.
All you have to do is thoroughly drench the soil and let the runoff drain through the soil. You may find the smell to be a little strong at first but it fades quickly and the benefits for your plants are definitely worth it.
When to Fertilize Indoor Plants?
It’s somewhat easy to figure out when to fertilize outdoor plants. Most of them come out of dormancy in the spring and prepare to grow flowers or fruits. A good rule of thumb is to fertilize after the first frost to prepare them for the spring and summer ahead.
But house plants are a little different. Because they aren’t exposed to changing sunlight and freezing temperatures, it’s not always easy to know when to fertilize them. Here are some general tips and tricks.
- Even though houseplants aren’t exposed to the elements, most of them are still dormant or semi-dormant in winter and do not need fertilizer. Fertilizing them at this time could result in weak growth and make the plant susceptible to diseases and insects.
- The exception to this rule is any plant that continues to grow through the winter. Any plant that is actively growing should be fertilized but use ½ or ¼ as much in the winter as you would in the summer.
- Plants that continue to bloom in the winter should be fertilized using the regular amount.
- Begin fertilizing dormant or semi-dormant indoor plants at the end of February. Even though they’re indoors, houseplants still sense the changing sunlight and can tell spring is on its way.
- If a plant is not doing well, do not over-fertilize it as this can kill the plant. Make sure it’s getting enough light and water and that the soil isn’t contaminated.
- Don’t add fertilizer to potting soil unless the product says it’s safe to use it that way. Potting soil often has fertilizer in it and adding too much extra can be harmful.
- If you’re purchasing a plant from a home and garden center or greenhouse, find out when it was last fertilized. Taking it home and adding more fertilizer can be harmful to the plant and is easily avoided.
How Often Should You Fertilize Indoor Plants?
Generally, you should follow the directions for the fertilizer you’re using and repeat fertilizer applications as often as they recommend.
How often you should fertilize your indoor plants really depends on the type of fertilizer you’re using.
If you use liquid fertilizer, you have a few options. Some formulas are meant to be applied each time you water. Others should be used every other time or once or twice a month for a bigger feeding.
That said, some liquid fertilizers can be used in multiple ways, depending on how they are mixed. Some products tell you very clearly what ratio of fertilizer to water you should use depending on what type of application you’re using.
Granular fertilizers should be used as often as the package recommends. These usually need to be applied pretty frequently, maybe once every two weeks or so. Because granular fertilizers release into the soil quickly, once the plant uses them up, the soil is ready for more.
Spikes, pods, and other slow-release fertilizers should be applied according to the package directions. They can last as long as two months or more, depending on how many you use and the size of your plant.
How to Fertilize Indoor Plants?
Again, this depends on the type of fertilizer you’re using.
With liquid fertilizers, read the instructions carefully so you know what concentration to use. Usually, you don’t need to use a lot, maybe only a teaspoon or tablespoon. If you can, use a liquid fertilizer that includes a measuring cup or spoon or has one built into the bottle. This helps avoid errors.
Some liquid fertilizers are meant to be applied directly to the roots. If this is the case, avoid the leaves as best you can so the bulk of the fertilizer gets to the roots. Other liquid fertilizers can be applied directly to the leaves. In this case, use a spray bottle and saturate the leaves well.
Granular fertilizers should be measured carefully and mixed into the top one to three inches of the soil. Remember, granular fertilizers release their nutrients pretty quickly after watering so you want to make sure there are granules available for the entire root.
This type of fertilizer can also be mixed into the soil when repotting or transplanting a plant. Again, not all fertilizers should be used this way so make sure you read the directions for the products you’re using.
Finally, slow-release fertilizers should be inserted directly into the soil, about halfway between the stem of the plant and the edge of the pot or as close to the waterline as you can get.
One of the problems with slow-release fertilizers is that they release a concentrated amount of fertilizer around the area of insertion but that doesn’t necessarily mean that the nutrients are getting to all of the roots.
To offset this, make sure you place the spikes evenly around the plant, especially if you have a large plant and are using multiple spikes or pods. This helps even out the distribution of nutrients and can help your plant grow better.
It’s not always easy to find good fertilizer for indoor plants. There are so many different brands to choose from, it can be hard to know which ones really work.
One of the main things to keep in mind is that you have to know your plants. Spend some time researching your plant to learn more about when and how it should be fertilized.
If you’re looking for something that you can apply and forget about for a while, go for a slow-release formula that you only need to apply a few times a year. All you have to do is push them into the soil and you’re covered for weeks to months.
If you like to have a lot of control over how much fertilizer you’re using, try a liquid fertilizer. Since you can apply them every time you water, you get precise control over the amount of fertilizer your plants are getting, and when it’s applied.
Finally, if you want something that’s easy to use, go for granular fertilizer. There’s no mixing and no messy liquid, just sprinkle them on, mix them into the top layers of the soil, and water as normal.
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