Fertilizer: What's the Deal?

As our plants head into active growing season, fertilizer has been on our minds.  Do I really need to use it? What kind should I get? What if I do it wrong and damage my plants? 

It's easy to become overwhelmed before you've even started!  This week, we'll do our best to point you in right direction to become fertilizer savvy.

Ever wonder how we keep our stock green and glowing? Keep reading!

What is fertilizer?

Within the word fertilizer is the word "fertile", which means "capable of producing abundant vegetation" (thanks, dictionary.com).  So, when we fertilize our plants, we are adding nutrients to our soil in order for the plant to grow more abundantly.

There are six main nutrients plants need to thrive.  You won't find the first three in fertilizer because they are readily available in air and water: carbon, hydrogen and oxygen.  The remaining three are nitrogen, phosphorus and potassium. They come from the plant's soil and thus, are the main active ingredients to houseplant fertilizers.  To learn more about what role each of these nutrients plays, click here.

Almost all fertilizer is intended for application in the soil of your plant.  One exception is air plants, of course, because they have no soil.  Check out our article on air plant care to learn more. 

Some plant parents encourage feeding the leaves of your plant too, just be cautious that you do not feed your succulents this way.  Tropical plants and ferns do well from spraying leaves with liquid nutrients, but it can cause rot and other problems with succulents.

Applying liquid fertilizer to succulent leaves can cause rot and other problems.  Be sure to apply fertilizer only to their soil, as indicated by the instructions on the bottle.

Why do I need to fertilize?

Normally, Mother Nature would be feeding our plants with the nutrients they need.  However when plants are pot-bound in our house, the nutrients in the potting soil are limited.  This is why we, as plant parents, need to provide the proper nutrients to our pot-bound babies.

Even if you start with great soil, as your plants grow, they absorb nutrients and leave the soil less fertile. By fertilizing your houseplants, you replenish lost nutrients and ensure that your babies have the food they need to flourish.

When should I fertilize?

Most houseplants in the Northern Hemisphere (what up, North Carolina!) actively grow during the spring and summer.  This is known as the active growing season. It's during this time your plants will need more nutrients to build their new plant tissues.

Regular use of fertilizer is recommended from mid-April to September for plant parents in the Northern Hemisphere; from mid-October to March for plant parents in the Southern Hemisphere.

Which fertilizer should I use?

There are lots of different types of fertilizer you can use. The basic rule of thumb we use when selecting a fertilizer is an equal part ratio of (e.g. 5-5-5) of nitrogen, phosphorus, and potassium.  All plant fertilizers are required to have this information on their label, so if you don't see it, don't use it.

We like to keep it pretty simple and stick to an all-purpose fertilizer on most of our houseplants. You can pick some up from us in-store or online. For succulents and cacti, we like to use a special cactus blend, and for our air plants, we use a special air plant liquid mix.

We like liquid organic cactus food for fertilizing our succulents and cacti.

Types of Fertilizer

Fertilizers come in several different varieties: liquids, sticks and tablets, and granular and slow-release forms.  Sticks and tablets seem convenient, but they don't distribute nutrients very well through the soil.  We recommend using liquid fertilizer or slow-release fertilizers for houseplants.

No matter the type of fertilizer you use, always read and follow the application instruction the bottle or bag.


Liquid fertilizers are added to your watering can. Depending on label instructions, you might fertilize every time you water, or every other time. Check the label and follow the instructions.

Slow-release / Granular 

Slow-release fertilizers are coated in time-release pellets that distribute nutrients into the soil.  This occurs over time because the individual pellets have coatings of different thicknesses that dissolve in the soil at different rates.

We like liquid organic indoor food mix for fertilizing our tropical houseplants.

In addition to fertilizer, what kinds of other supplements can I give my plants?

Apart from the six main nutrients plants need to thrive (carbon, hydrogen, oxygen, nitrogen, phosphate and potassium), certain plants also appreciate other minerals like calcium and magnesium.  Instead of buying a bunch of different fertilizers to meet specific needs of just a few of your plants, why not use items already in your home?  Here are some tricks we like to use.


Eggshells are filled with calcium, which is essential for plants to develop a strong cellular structure.  Learn more here.

Try it with: Any houseplant


Brewed coffee grounds contain a good amount of potassium and magnesium, which are excellent for plant growth.  Go easy with this one - too much acidity in the soil can be harmful.  Learn more here.

Try it with: Aloe, fern

Epsom salt

High quality Epsom salt is rich in magnesium and sulfate, two minerals that together provide incredible nourishment for plants, allowing them to grow fuller and greener, and live longer lives. Learn more here.

Try it with: Fiddle leaf fig, peace lily


What do you use to fertilize your plants?