Container Gardening Mini-Series: Fertilizer

Welcome to the third installment of our Container Garden Mini-Series. Today’s post is a bit more lengthy as there’s lots of info I want to share with you.

First, to catch up on this mini-series, you can read Parts One and Two by clicking below:

Part One:  Commitment                             Part Two:  Water

Container Gardening Mini-Series: Fertilizer

May 13: Sage shrub plant happily blooming!
(We even saw a green hummingbird feeding on it!)


Today’s Topic?


Fertilizer is especially important for container gardening, because all the nutrients that can benefit the plants [in a container garden] must be drawn from the soil in the container.

Start with a good quality garden soil. There are many brands of potting soils for sale at your local home improvement store or nursery. Even the big-box discount stores have garden departments this time of the year too.

If you are growing vegetables in containers, my suggestion is to use organic potting soil to keep your vegetables free from chemicals that you would rather not eat.

There are two main types of fertilizer: time-release pellets or spikes that provide nutrients just a little bit each time the containers are watered; and there is fertilizer in powder or liquid form that, when mixed with water, provide your containers with a good amount of nutrients.

Time-release fertilizers are a good choice to add to your containers at the start of the growing season in the Spring. Once you sprinkle the small pellets around the plants, or stick the spikes into the dirt, your containers will get the nutrients they need over a period of time of up to three or four months. Read the information on the version of time-release fertilizer you choose for specifics and application directions.

Liquid fertilizers are mixed with water and applied to your containers during a typical session of watering. Usually these fertilizers provide nutrients for a short time and will need to be reapplied every few weeks throughout the growing season. Again, specifics on the packaging will provide good directions on frequency of application and how much to use each time.

Which type of fertilizer you choose is completely up to you. If you don’t want to be bothered with having to remember to fertilize every few weeks, go with the time-release fertilizers.

What are you planting?

Answering this question will help you determine what ingredients your plants need. For example, foliage plants need lots of nitrogen for their color and health; whereas flowers and vegetables need more phosphorous and lower nitrogen.

Wait a minute.

You don’t want a chemistry lesson and neither do I. Just remember to really take stock of what you’re growing and buy a corresponding fertilizer. All the major brands will list which types of plants they work best for, right on their packaging: flowers, evergreens, flowering shrubs, fruits and vegetables, organic versions and so on.

What do I use?

Before I answer this question, I want to direct you to the disclaimer I shared during the Commitment part of this series, reminding you that I’m not a professionally trained gardener. Click here to read!

I use a combination of fertilizers in our containers. (Please note that I’m not being paid or sponsored to share my favorite brands with you. This is simply me telling you what I personally use on a regular basis.)

Espoma Holly-tone.The Espoma company has been around since 1929 here in the USA (gotta love that!), and specializes in natural and organic fertilizers and potting mixes. Here’s their website so you can learn more. We use their Holly-tone every year. Espoma also makes “-tone” versions for Roses, Trees, Vegetables, Tomatoes, Bulbs and more. All of their tone products are organic, won’t burn your plants like some chemical fertilizers can, and are safe for people, pets, and the environment. As we hope to add at least one dog to our furry family some day, we prefer to use pet-safe products as often as possible.

Holly-tone is formulated for acid-loving plants and shrubs, in fact quite a long list of them too – right on the package. As we have Azaleas, Evergreens, Heather, Magnolias, Holly, Hydrangeas, and Junipers, we apply Holly-tone in the Spring and Fall. As more and more people have discovered the ease of planting small shrubs in containers, using an acid-loving plant food is a must.

You just sprinkle it around the plant right on the soil, and then cover with your choice of mulch. We simply move the mulch away from each plant with a small rake, sprinkle, then rake the mulch back into place. I can’t tell you what Holly-tone specifically does – you can read the packaging for the science part of how it works – but I can tell you that our acid-loving plants are quite happy and healthy, with good color foliage and needles plus beautiful blooms.

Osmocote. Osmocote is a time-release fertilizer, owned by the Scotts/Miracle-Gro Company. Here’s their website so you can learn more. There are several different versions of Osmocote for vegetables, flowers, indoor plants, etc. We use the Flower and Vegetable version in the green bottle.

We sprinkle this around our garden plants in the Spring, and know that for the next four months our plants will be taken care of. As we do with the Holly-tone, we sprinkle this right on the soil, and then cover with mulch. This season, we have begun to add some of this into the bottom of new planting holes (both in gardens and containers) and mix it with dirt too. Why? Well, our neighbor says doing just that is what makes his gorgeous Begonias grow like flowering shrubs each year. (And they are GOR-JUSS!!!)

Most recently, we used Osmocote when we transplanted our Sage shrub plant (it is HUGE!!!) into a larger container. Within a week it was blooming happily in its new home, as you can see in the images. (Yes, normally you don’t want your sage to flower. After our mild Winter, it began blooming already in April. We decided this one will be ornamental, and we will purchase another one for our own use as an herb.) Did I mention how huge this plant is? We love it!

I’ve spotted both Holly-tone and Osmocote at the major home improvement stores and at most garden nurseries too.
May 7: Newly transplanted sage shrub plant.
(You can see some Osmocote pellets on the soil.)

Scroll back up to the top of this post to see the transformation!

An extra tip for today:

Are you a total newbie when it comes to container gardening?

Make it easy on yourself this first year, and purchase the gorgeous pre-planted containers you see at your local nursery or home improvement store. This is a fantastic way to introduce yourself to the world of container gardening.


  • containers already planted for you
  • you can read up on the plants included, begin to learn their needs
  • if they die, you can blame the store – just kidding!

Consider this the “cliff hanger” in our Mini-Series, as I’m sure this won’t be the last time I talk about container gardening. So stay tuned!



  1. says

    More great advice! I’m going to check out the fertilizer, Hailey wants a “green, green, garden” and I don’t want to eat chemicals if we eventually end up with any edible veggies. 🙂