A few years ago a young woman asked me for help with her large, potted acacia tree. “I’ve had it for several years, and it was doing fine until recently. Now, the leaves are yellowing and dropping, and it’s just not thriving.”
This geranium blooms nonstop, thanks to regular fertilizing and top-dressing with worm castings.
“Let me guess, I’ll bet you’ve taken good care of it, and have been feeding it with liquid fertilizer, but despite your best efforts, it’s still suffering, correct?”
“Exactly!” she exclaimed.
I knew immediately what was wrong. Handing her a 25-pound bag of dried worm castings and 20-quart bag of potting soil, I instructed her to re-pot the tree in a 50/50 mix of the two, add the recommended amount of her liquid fertilizer, water it well, and call me in a month.
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If you live in Vermont, consider attending a seminar, taught by Mike Ather, the author of this post.
Worm Composting: 9:30-11 a.m. Jan. 25 at Gardener’s Supply, 128 Intervale Rd., Burlington, VT.
Love to compost and want to continue through the winter? Consider vermicomposting. A worm composter works faster than a traditional compost pile and can provide a wonderful educational opportunity for kids and adults. Join Master Composter Mike Ather and learn the how it’s done. Learn more and get the full schedule of seminars.
Just about thirty days later, instead of calling, she came to see me. With a huge smile she excitedly exclaimed, “My acacia is growing new, bright green leaves! What’s up with that?”
In addition to the nutrients (NPK) found in water-soluble fertilizers, all plants require a range of other nutrients and beneficial bacteria to maintain their health and vigor. In nature, these are delivered by the action of bacteria, fungi, microbes, earthworms, insects and other tiny creatures that convert soil minerals into plant food.
But in a container, it is just a matter of time until secondary nutrients and vital trace minerals are depleted — even if you use top-quality planting mix. Once this happens the plant fails to thrive.
The Worm Factory, a worm composter
Worm castings can replenish all of these nutrients. Containing more than 150 plant vitamins and trace minerals, worm poop also has beneficial enzymes, hormones and bacteria that plants crave. In addition, the crumbly structure of castings helps promote good soil aeration.
To boost houseplants in decline, simply re-pot in a blend of worm castings and good potting soil. A 50:50 ratio is ideal, but you can get by with as little as 25 percent worm castings. For healthy plants, sprinkle a tablespoon or two of worm castings on the soil surface every other month. Don’t forget to feed regularly with liquid fertilizer.
In my sunroom, I have a 14-year-old geranium that gets top-dressed with worm castings about six times a year. It always has bright green foliage and is rarely without a blossom.
Dried worm castings, such as Worm Power, can be purchased at most garden centers, or for superior, potent, biologically-active castings, make your own with a worm composter. To learn how, read the article Worm Composting
Hi Mike – I realize this article is several years old. I have a Monstera deliciosa that is about 10′ tall. It would be difficult if not impossible to repot without damaging the plant since it is essentially a thick vine and is only held upright by a large stake. Can I blend in worm castings to the top of the soil instead of repotting it in new soil with the worm castings. — thx
I would say yes, mix the top few inches with worm castings and then the water will carry the nutrients from the worm castings to the plant roots. I have a lot of plants and just add a few tablespoons of the castings to the pot every few months, no plants have died as a result so they must like it.
Hello..I would like to add a few spoonfuls of work castings to help with the fungus gnats larva. Would this help? Just want to make sure I’m doing the right thing.
Here is some information about combatting fungus gnats: https://www.gardeners.com/how-to/fungus-gnat/7317.html
What would be the best houseplant liquid fertilizer? One that can be used on multiple differential plants. Thank you.
We offer a variety of options here. https://www.gardeners.com/collections/liquid-fertilizer
I use worm castings, you mentioned to not forget liquid fertilizer. What would be an example of liquid fertilizer? And do I use it in addition to worm castings?
We offer a variety of liquid fertilizers (and water soluble ones). https://www.gardeners.com/collections/liquid-fertilizer You can use both — especially in an outdoor environment where you’re growing heavy-feeder annual flowers, etc.