Worm Castings – How well does it work?

This spring (May, 2023) I got the surprise of my life! I had always believed that having worms in my garden or plant soil brings much to the soil for many reasons, one of them being that worm castings is the nourishment par excellence for the plants. But I had not realized to what extent worm castings can help plants grow and flourish.

(Before telling you my experience with worm castings, I thought it best if I tell you that I had always had gardens and flowers growing in a big back yard until 2004 when I had to move to an apartment which has a balcony.  Here’s where I am doing all my experimenting with container gardening on a balcony facing north west.)

Last fall (October, 2007) when I was cleaning up my balcony and mulching a few of my plants for the winter, I decided to transfer three of those 2 1/2 ft. long by 5 1/2 inches wide ( approx. 72 cm long by 14 cm wide) balcony window boxes into my living room. Two of the three window boxes each had one amaryllis bulb in it; the third window box I filled with soil only and would use it exclusively for vermi-composting.

I also brought in a 10-inch pot which contained three geranium plants which seemed to be slowly dying. I placed this flower pot on a table in front of my only window which got the sun – albeit only in the morning, but it was better than no sun at all. I just could not bring myself to throwing the geraniums in the outside compost.

As for the three window boxes, I placed them in one row on the floor behind my couch whose back was towards the patio door which faces north. The containers would thus be out of sight for anyone entering the apartment.

Once I had installed the three window boxes behind my couch, I went to the bait store, bought a dozen red worms, and put half of them in the container with soil only and the remaining worms I split up between the other two containers.

These reddish worms were not the small wigglers you find in composted manure, but they were the only worms available at the time. I could have used dew worms, but I don’t like handling those for they are much bigger, and I did not fancy having those in the “compost bin” behind my living room couch. (I live in an apartment).

I didn’t know then that worms love raw Quaker Oats that is used to make oatmeal, so I fed them chopped-up leftover lettuce, celery, carrot tops etc.. ( I felt it was important to break up the food in little pieces and bury most, if not all, in the soil. After all, no sense in attracting flies). Since the food was disappearing, I knew the worms were happy.

Two months went by. Once in a while I would dig into the soil to see what I would find. Soon I could see baby worms here and there, and that told me there was activity in that 3rd window box.

Meanwhile, all summer and fall the amaryllis bulbs had sprouted only green leaves, so after they had been inside for a few months they were neither growing nor dying, so I decided I would again try to use liquid synthetic fertilizer around the plant in the first window box and see if I would get results.

The next morning, to my dismay, I saw that the worms in that 1st window box had crawled out and were almost dead on my wooden floor. It then dawned on me that if the liquid fertilizer was too strong for the worms, how could it help the plants?

Right then and there I decided that was it! No more using liquid synthetic fertilizer. I had seen first hand how much worms evaded this stuff like the plague!

I picked up the worms and threw them in the 3rd window box with the bulk of the worms so they could revive fully. Then I watered the bulbs in that 1st window box to try and leach out as much of the liquid fertilizer as I could.

Since by this time the worms in the 3rd window box had had a few months of being fed and leaving worm castings behind, I decided to experiment.

Taking my little hand trowel, I dug out some of that soil that contained the worm castings (made sure I was not including the worms), spread it as top soil all around the bulb plants, and watered with tap water which was at room temperature. (I run the water in containers about a day before I use it so that the chlorine can escape out of it; in addition,  the water is warmer.)

Lo and behold, even though these amaryllises were in front of a north window and got little, if any, sun (don’t get much sun in the winter anyway), a new shoot started growing and growing. Soon I was admiring a beautiful amaryllis; four beautiful white trumpet-like flowers were peeking at me above the back of the couch. These white flowers were accompanied by another red amaryllis.  I was impressed!

(Click on the thumbnails for a better view.  1. the two amaryllises (from the front of the couch ) 2.  a behind-the-couch view of the plants and 3. a view of the vermicomposting bin.

I figured that would be the end of the flowering for a while, but soon after the first trumpet-like flowers had died down, another shoot started growing. The plant flowered three times in a row! Each time the stem was nice and strong and the flowers were healthy and beautiful! Wow!

Unfortunately up to this point I had continued using liquid fertilizer to feed the geraniums even though two of the three plants had died leaving me with only one geranium in that large 10-inch flower pot. So when the worms reacted so strongly to having fertilizer in their window box, I decided to switch my feeding habits.

I immediately stopped using liquid fertilizer to feed the geranium. Instead, with my little trowel I dug out some soil that contained the worm castings in it from the 3rd window box, and spread this compost as topsoil all around the one remaining dying geranium.

Before long, I saw a major shift. The geranium’s stem was getting stronger and one morning when I walked into the room, I suddenly realized it had sprouted a beautiful hot pink flower. As time went on, a second one came forth, then a third and up to six at a time with more beginning to grow.

Click on this picture and you will clearly see the large empty space on the left hand side of the pot where the other two geranium plants had once been.

Notice how vibrant and lush this surviving geranium looks. I did put soil with worm castings a second time, but that was all I did except for regular watering.

Here’s another proof that worm castings work. In the spring of 2006 I had planted a climbing rose called “Joseph’s coat of many colors” in a big container on my balcony, but it had not done very well. I had very few roses and it never looked that healthy. It did not survive the winter.

Although in the past I had grown these climbing roses for years in my flower garden, in the spring of 2007 when I saw my precious climbing rose had died, I figured I would not be able to grow one of these beautiful climbing roses again as long as I would be in an apartment. I thought that never again would I be able to enjoy those beautiful roses which keep changing color as they age nor be able to smell that superb heady fragrance on the night or early morning air.

Well, after experiencing success with the geranium and the amaryllis, I decided to buy a young “Joseph’s coat of many colors” a few weeks ago and mixed in some of my worm compost with the soil in the bottom of the hole where I inserted the plant. As well, I mixed the worm composted soil with the soil that was used as fill around the plant.

The rose was planted about two weeks ago (April 26, 2023), and even though the weather has remained quite cool, the plant has survived the transplanting procedure very nicely.

It now has seven strong healthy-looking stems about 12 to 15 inches long, and each stem ends with a small flower bud. Click on the picture for a better view. See how lush and healthy it looks.

I think this “Coat of Many Colors” will survive beautifully. Of course time will tell.

Yes, I am sold on using only this vermi-compost, these worm castings, to feed the plants in my balcony containers. Worm castings work fabulously well!

The nice part about it is that after taking out some or all of the composted soil, I simply add more soil into the window box container, add the food, and let the worms do the rest.

This summer, the only fertilizer I will use for all my balcony plants will be the soil which contains worm castings in it. I simply place this compost around the base of my plants and every time I water, my plants will be fed with the best plant nutrition possible.

Happy Composting!


Photo by sippakorn yamkasikorn