Updated: November 6, 2026
What Are Worm Castings?
Looking for a gentler way to feed your plants than many chemical fertilizers? Let’s talk about the benefits of worm castings. Also known as vermicompost, they are a great way to give your garden soil and plants a little extra love. (Want the full rundown? We’ve got a deeper look at what worm castings are.)
Castings from composting worms are a natural fertilizer with plenty of nutrients and minerals, like nitrogen, potassium, magnesium, calcium, and phosphorus.
Because they are a purely organic fertilizer, worm castings can help your plants grow better, support healthier soil, and help the soil hold on to moisture. If you want a steady supply, you might want to start your own little worm farm with red worms.
Red worms live off organic scraps, including the ones from your kitchen or yard. As they munch through them, they turn those scraps into a richer, plant-friendly fertilizer. And since the worms have already done the breaking down, plants can absorb the nutrients more easily than from fresh animal compost or some chemical fertilizers, which need more time to break down first.
Earthworm Castings for Amazing Plant Growth
Vermicompost is full of good stuff: water-soluble plant nutrients, helpful bacteria, enzymes, and bits of organic matter. The mucus and tiny mineral clusters the worms leave behind help the soil hold on to water and nutrients.
Earthworm castings also bring beneficial microbes into your soil, which helps keep it healthy and lively.
Like the classic movie line, “if you build it, they will come”: the moist, cozy environment that comes with worm compost in your garden can attract even more worms. The more worms around, the more fertile your soil tends to get, and the more you get to enjoy the benefits of worm castings.
Healthy, living soil gives your plants a strong base to grow from, and it can help them handle the ups and downs of the season. Some gardeners also find that castings help keep pests away from their plants.
If you want to start enjoying the benefits, grab a worm bin and start your very own worm farm today! And if you’re not ready to start worm farming, we’ve got you covered with our very own “black gold”. Curious about how it works? Read how Black Gold helps plants grow.
Can You Use Worm Castings on Houseplants?
Yes, and houseplants tend to like them. Because worm castings are gentle, you can mix a little into your potting soil or sprinkle some on top and water as usual. We break down how much to use and how often in our guide to worm castings for houseplants.
Making Worm Castings
(Source: Pinterest)
So how do you actually make worm castings at home? Uncle Jim can help you with that.
Worm castings are, in plain words, worm poop. It’s a fancy name for something that happens naturally during the vermicomposting process: your worms eat the kitchen scraps you give them, and what they leave behind is the castings.
Our vermicomposting for beginners guide lays out everything you need to know to set up a worm farm and keep it happy, so you can harvest your own castings regularly.
How to Harvest Worm Castings
(Source: Pinterest)
Here are some ways you can harvest worm castings:
- Worm Relocation: Worms like to move toward food. If you push the uncomposted scraps to one side, the worms will follow, leaving their castings behind for you to collect.
- Hand Harvest: A slower method, best if you like to take your time. Pick out a few castings at a time, or empty the tray and sift through it. Then put everything back and add more scraps.
- Screen Compost: Sift the contents of the bin through a screen. It separates the worms and other bits from the finished compost.
Here is a more in-depth guide on how to harvest worm castings.
Frequently Asked Questions
What Is Worm Tea?
Worm casting tea (or worm tea) is made by steeping worm castings in water. It’s a popular way to give your plants a boost of beneficial microbes. All you need is worm castings, a porous bag, a bucket, and dechlorinated water. Here’s a simple way to make and use worm tea.
Are Worm Castings Better Than Compost?
Both worm castings and regular compost bring nutrients to your soil, help it breathe, and are gentler on plants than many chemical fertilizers. The main difference is timing: since the worms have already digested the organic matter, plants can use the nutrients in worm castings more quickly. Regular compost needs more time to break down first.
Want to compare them side by side? Read compost vs. worm castings, or dive into our complete worm castings guide.
And if you’re ready to start your own farm, Uncle Jim’s has earthworms for sale! We take great care packing these hard workers so they arrive alive and in one piece from our farm to your home.
17 thoughts on “The Benefits of Worm Castings on Garden Soil & Plants”
I’ve bought worms the past 3 years and each year they have just disappeared by summer’s end. I live in the upper West desert area in Arizona and have a lot of gopher problems. I use the vibrator sticks to help keep them out of my flower and garden areas, could the vibrations be affecting the worms also? Please help.
worm activity can be distracted from vibrations but if only few hours in a day it will be fine.. if you want to propagate your worms check twice a week if moisture condition is ok. never leave it dry or they locate for better places and if they cant, they will just die.. keep feeding with degredable or decaying matters, (left over,peelings, and uprooted weeds that will decay).
Great article on the benefits of worm castings!
I can personally say that what you state in the article is very true, I have been using my own in house worm castings for 4 or 5 years now front seed starting to gardening throughout the season. I see healthier plant starts, Healthier plant growth including longevity and increased yields by using the castings in the garden during the growing season. I have even used them to repair dead spots in my lawn that nothing else worked on. Great article!
I am starting a big garden and I’m going to buy your worms, and was wondering for my soil what can I add so that the worms can have food but not hurt my plants?
These natural fertilizers are very helpful to plants. Thank you for sharing this article. Really helpful and informative. Hope to read more from you.
Do desert rose leave poison my worms
Hello David!
We would not recommend that you add them to the worm bin. There are no studies on this but it is not worth taking the chance since the Desert Rose does contain toxins.
I’m trying to make my garden nicer instead of using manure, do you think worms would be better fertilizer?
I want to become a gardener, I think I should use manure for fertilizer because I don’t have worms. Is that okay?
Hi! I am starting a garden, and right now i’m using my cows manure as fertilizer, but I saw that worms are better fertilizer, and wanted to try silt fencing and worms, but what type of worms are best?
Hello Maria;
We recommend that you add the European Night Crawler for in the ground or raised bed gardens. They are a hardy worm that can live off of the nutrients in the soil and burrow deeper which helps to protect them from the elements. We recommend that you add 5-10 per square surface foot of soil.
Uncle Jim’s Worm Farm
Thank you very much! I will gladly do so, thanks again!
To my dismay, I almost cried but held back the tears. I tried to to make a large worm casting bin out of those large iron containers sold at Home Depot. I had a friend help me set it up.I do believe that that bin became too hot. I will stick to my 5 gallon bucket in my 4by20 raised bed garden. My worms all died!. Now I will make the large container into another large raised bed garden.I plan to put three more 5 gallon buckets in other 4by20 feet garden. (2 buckets each in the two 4’by20′ raised planters I had built three years ago.)(SIGH….) Thank you for all your help and I will be buying more products and some more worms in the near future.
I have prior experience using worm casting in my garden with great results. I just assembled a greenhouse and am adding worm casting to all my plants andnI am starting a worm farmmso I appreciate receiving the free worms I won!
I liked how this post shared that worms tend to move places where the food is. My friend wants worm-casting composting for her garden. I should advise her to go for it to enhance her garden.
I like how you said that it is an organic fertilizer that can help protect your soil and plants! Last night, I was at my sister’s house for dinner, and she talked about how she and her husband want to look into starting a garden in their backyard before the end of the month, so they want to make sure they get all of the right supplies. I’ll pass this information along to her so she can know the advantages of using worm castings.
Hello, How much worm casting do I need to make 5 gallons of worm tea?