One thing nobody warns you about when you first start collecting houseplants is the sheer number of products available on the market. From tools you've never heard of before, to smart gadgets designed to take care of plants for you, and a large number of different fertilizers promising to deliver different results.
It can be overwhelming to navigate this and figure out what exactly you need to add to your plant care kit. The best fertilizer for houseplants, for example, isn't one single product. Just like us, plants have differing needs and go through periods of good and bad health, as well as a growth cycle that requires different essential plant nutrients at different stages.
For this reason, you may find you need to invest in a few types of houseplant fertilizer throughout the year. To help you out, I spoke to plant experts to find out more about which types of houseplant fertilizers rank best and when to use them - here's what they told me.
How to choose the best fertilizer for houseplants
Before picking up the best fertilizer for houseplants, you need to have an understanding of what fertilizer does for plants. This way, you will have a better insight into what your plant needs at that point in time and which products to choose as a result.
Essentially, fertilizer is plant food that contains a boost of nutrients needed for growth. By adding it to the soil of your houseplants, you replenish the nutrients that naturally deplete over time, which plant roots then soak up to support plant health. Different fertilizers will contain different nutrients, providing the plant with certain support.
'I like to remind people they should never assume that they have to fertilize,' says C.L. Fornari, gardening expert and author. 'Adding excess nutrients where they aren't needed can be harmful to plants,' she explains.
There are some houseplants you don't need to fertilize often, and others that are heavy-feeders. It's all about researching the needs of the indoor plants you grow and understanding whether they benefit from feeding.
Not only this, but you also need to identify whether their current state would benefit from a boost of nutrients - e.g. is your plant about to flower? Or, perhaps it's recovering from pest and disease damage.
Here, experts share insights on the best fertilizer for houseplants in different circumstances.
Best fertilizer to support overall houseplant health
When shopping around for the best houseplant fertilizer, you likely would have stumbled across the phrase 'balanced fertilizer.' This refers to the plant fertilizer numbers - three numbers on the packaging of products identifying how much nitrogen, phosphorus, and potassium they contain. A balanced plant food is one where all three are present in even volumes.
These are macronutrients plants need for general good health and strong growth. Nitrogen encourages vegetative growth, phosphorus supports flower and root growth, and potassium helps move water and nutrients around the plant. If you're looking for a fertilizer to support all of these aspects of plant growth, a balanced fertilizer is a good one to opt for.
'I would use a fertilizer with a balanced NPK like a 20-20-20 liquid fertilizer,' says Lisa Eldred Steinkopf, plant expert at The Houseplant Guru.
You can get water-soluble balanced fertilizers, as Lisa notes, which you apply by mixing with water and then watering your indoor plants. Or, you can opt for a balanced slow-release fertilizer - these are granular products typically made from organic materials that provide a consistent feed for weeks, or months, at a time.
'Organic granular fertilizers also tend to reduce the danger of causing fertilizer burn on your plants,' explains C.L.
It's true that a fertilizing mistake is using an excess of fertilizer, particularly in liquid form, which can cause root burn and damage your plants long-term. That's why it's key to always follow manufacturer instructions for the products you use.
Not only this, but you should also stick to only giving your plants a balanced fertilizer - or any fertilizer - during their active growth season. This is typically in the warmer months, but it's worth researching the growth cycle of the specific houseplants you have.
This 2 pack of balanced indoor plant food is water-soluble. It feeds plants instantly and is appropriate for a wide range of houseplants.
This 10-10-10 granular fertilizer releases essential nutrients to plants slowly, providing up to 8 weeks of sustained nutrition. It can be used in the yard and on houseplants alike.
This is specially formulated for the unique needs of common indoor houseplants. Equal parts 10-10-10 NPK to support overall plant health.
Best fertilizer to encourage leafy growth
As previously noted, vegetative growth is what nitrogen does for plants, and you might seek a nitrogen-rich fertilizer when encouraging a houseplant to push out new leaves - especially during its active growth season in spring and summer.
'If you want new growth, use a fertilizer with a higher first number,' Lisa says. This is the number showing how much nitrogen is in plant food.
'Use them at the start of the growing season,' C.L. advises. This will prepare your houseplant's soil with a boost of nitrogen for roots to take up during the time it is most heavily feeding.
Again, you can either opt for a nitrogen-rich liquid indoor plant food (like this indoor plant food from Amazon or this tropical houseplant fertilizer from Walmart), or a nitrogen-rich slow-release fertilizer. However, experts say it's best to use a liquid fertilizer for an instant boost of nitrogen when trying to encourage foliage growth.
You might also have heard of using coffee ground fertilizer for houseplants. This is an organic option, with coffee grounds being rich in nitrogen. However, be aware that wet coffee grounds sitting in a houseplant pot could attract common houseplant pests.
Best fertilizer for indoor flowering plants
Indoor flowering plants often require a different type of houseplant fertilizer to leafy kinds, especially during their blooming period. This is because a good level of phosphorus is required to support flower growth.
'Look for a bloom booster or fertilizer with a high middle number (phosphorus),' advises Lisa. 'It won’t make your houseplants bloom, as many believe. Instead, it can make the flowers more vibrant, larger, and even last longer,' she explains.
It's true that a phosphorus-rich bloom booster fertilizer (from Amazon) won't make an indoor plant flower, but it will bring a more impressive display of blooms. You need to ensure your flowering houseplants have sufficient light if you want to see them bloom in the first place. You can then apply a bloom boosting fertilizer just before its flowering season to encourage a brighter, more abundant showcase.
Something to note, however, is every flowering plant will have different lighting requirements:
'A plant such as Christmas cactus blooms because it's been given longer nights and cool temperatures in September and October, for example,' C.L. explains. For this reason, always research the needs of your indoor flowering plant and meet essential growing requirements before adding a fertilizer into the mix.
Of course, different indoor plants that flower all year round have different nutrient needs. That's why you can also choose to use specific plant fertilizers - whether you need to fertilize a peace lily, fertilize an orchid, or fertilize African violets:
This peace lily fertilizer is designed to promotes lush foliage and vibrant blooms.
This specially formulated, slow-release fertilizer is perfect for all varieties of orchids.
FAQs
Do recovering houseplants need fertilizer?
It depends on the time of year and what your houseplant is recovering from. Fertilizer should only be given to plants during their active growth season, otherwise they may run into issues of houseplant root rot or root burn. If it's fall or winter, it's generally best to avoid fertilizing your recovering plant and instead focus on providing an optimal growing environment. If, however, your houseplant has experienced some damage from pests in spring or summer and is now showing signs of recovery, providing a balanced or nitrogen-rich fertilizer can help encourage regrowth of foliage.
'I would use an organic fertilizer that has no synthetic ingredients because it can be easier on a weak plant,' says Lisa Eldred Steinkopf, plant expert at The Houseplant Guru. 'Organic fertilizers are better because they are less likely to burn the plant like synthetic fertilizers,' she explains.
Be aware that in many cases houseplants recovering from severe damage will not favor fertilizer. It may cause shock or further damage. It's therefore best to always research the best way to revive your plant from the problem it is facing.
Can you use organic matter to fertilize houseplants?
Yes, you can use organic matter to fertilize houseplants. It's for this reason many people choose to use banana peels as fertilizer, as well as coffee grounds, and eggshells which are good for plants. However, something to keep in mind when using organic matter on houseplants is you could attract a range of pests to your home. Likewise, it may leave your interiors with an unpleasant odor, or a build-up of mold in your plant's pot as some common organic fertilizer materials take a long time to fully breakdown.
The best fertilizer for houseplants really does depend on the specific plant you're growing and what it needs at that point in time. For example, while it's not recommended to feed the majority of plants during the colder months, some houseplants should be fertilized in winter ahead of the spring season. Likewise, C.L. Fornari reminds us to 'never assume that fertilizer is the answer to a plant's problem.' There could be a range of other factors impacting your plant's health, such as a lack of light. If this isn't addressed, you could find yourself making common indoor plant mistakes that lead to the death of your plant.
