Learning Center


Feeding Your Houseplants

Feeding Houseplants

Why Fertilizer is Important

Houseplants are like any other plant in that they need nutrients and micro nutrients.  Generally speaking, they are usually planted in a soil-less potting mix that doesn’t have many, if any, nutrients.  This means that their entire nutritional needs rest on us as houseplant parents.  Sometimes, when purchasing a houseplant, you will see little green or yellowish round pellets on the soil surface.  This is fertilizer that the grower applied; much of which gets lost in shipping.  The houseplants then hang out at the garden center for at least a little while, and may or may not get any additional fertilizer before adopted and taken home with you.

If you don’t have any houseplant appropriate fertilizer and you are adopting some houseplants, pick up a fertilizer as well.  Your houseplants won’t tell you they need nutrients until they really need them, and the signs can be as subtle as slowed growth or less vibrant leaves.  Plus, it can take some time to recuperate them.

Choose a water soluble or time release fertilizer that is recommended for the plants you choose.  Not sure what either of those are?  Keep reading!

Water Soluble Fertilizer

A water soluble fertilizer is a concentrated fertilizer (could be liquid or granules) that needs to be mixed with water, then watered onto the plants.  Most water soluble fertilizers instantly release nutrients that are ready to absorbed and utilized by the plants.  The most common one is Miracle-Gro and of course, our favorite, BR-61 which is like a bloom inducing steroid for annual color!  The most common fertilizers for orchids, cactus and succulents, as well as for African violets are water soluble.  Follow directions on each as both mixing rates and application intervals differ from product to product.

Water soluble fertilizers make a difference pretty quickly, since nutrients are instantly available.  Which is great if you remember to do it often.  If you tend to forget things like fertilizing plants, you might consider a time release fertilizer.

Most natural fertilizers for houseplants are water soluble such as Liquid Seaweed, and Compost Tea.  These fertilizers can smell a bit strong; you might want to water them outside on warm days. For tropical houseplants and succulents, make sure temperatures are above 55 degrees and don’t forget to bring them back in on the same day to avoid cold damage.  Tropical ferns especially love these types of fertilizers.

Time Release Fertilizer

Time release fertilizers are just what they sound like.  Nutrients are released at intervals instead of all at once, like with water soluble fertilizers.  These are also called slow release fertilizers.  Regardless, the action is the same; they release a small, steady amount of nutrients over a course of time. That course of time differs product to products so pay attention to application instructions.

For the plant nerds like us, here is an interesting tidbit.  Each little pellet of Osmocote is called a prill.  It consists of fertilizer covered with a polymer and vegetable oil covering.  This covering allows the prill to absorb water, then slowly release it back out of the covering into the soil. This fertilizer then bonds to the growing media, and is slowly absorbed by the plant roots.

When using something like Osmocote, the most common time release fertilizer we recommend for houseplants, use half the recommended rate.  Yes, half the rate, even for the one labeled Outdoor & Indoor Osmocote. Otherwise salts may build up in the soil; you would see this as white rings around the outside of a terra cotta or other porous pot, or on the soil surface.  A watering technique called leaching can help this; we wrote about this in yesterday’s post, here it is if you missed it.

Time released fertilizers last a lot longer than quick release fertilizers, so you won’t have to apply these near as often.  As a reminder, this fertilizer will be released much quicker at higher temps and slower at low temps so applications differ greatly from indoor plants to outdoor plants and seasonally as well.  One more reason to love Osmocote; it’s great on all kinds of things like annuals, houseplants, perennials, shrubs, and even vegetables and herbs.


This one gets it’s very own category.  SuperThrive is more like a vitamin mix for your plants… at least we think so.  The label is so crazy, it’s hard to tell what it has in it.  No matter, it works!  We suggest using this when making a drastic change in your houseplants location, like moving them from outside to inside for the cool season, inside to outside for the warm season or moving a Ficus benjamina from one place to another.  It really cuts down on the leaf drop or the ficus and overall, plant stress!

Adjust Rates Seasonally

Houseplants don’t go dormant but they do have a resting period, and it’s usually during the cooler winter season.  During this time, fertilize half as often or use half the recommended rate but at the regular interval.  For time release fertilizers, such as Osmocote, this could mean a quarter rate, since you are already cutting the rate in half for indoor plants.  Time release fertilizers release nutrients in reaction to both water and warm temperatures; so they release more in warm weather, less in cold weather.

Fertilizer Only Works When You Use It

Seriously though, it’s true.  We talk to customers about fertilizing and often times when we ask when they last fertilized, we get the head tilt, narrowed eyed, thinking hard look.  If you have to think that hard about when the last time you fed your plants was, you might need to come up with a better scheduling plan!  No matter which kind of fertilizer you choose, putting it in your calendar as a reminder is a good idea.  Or put dates of application on container to keep up with when you last fertilized.  We suggest some sort of reminder to keep you on track, because we get it, it’s easy to forget to feed your plants, and as you now know, feeding your houseplants is very important for their health and happiness!