We’ve all seen worms wiggling in the dirt. We’ve likely played with them as kids. Back then, they were great entertainment, but as a gardener, worms can take on a much more important role.
With my vegetable gardens, if I spotted a worm squirming in a pile of dirt, I would automatically move him to my garden so he could burrow in and do his magic. But these were in-ground gardens. What about a raised garden bed? Are worms okay for this type of garden?
You can put worms in a raised garden bed. However, raised beds need additional consideration. Although worms can provide the same benefits to a raised vegetable garden as an in-ground garden, it’s not a simple matter of sprinkling a few overtop your soil. The environment must be hospitable to worms so they will remain and thrive. Furthermore, worms should not be added to certain types of beds, such as elevated beds.
Read on to learn more about the benefits of worms, which beds shouldn’t have worms, and how to add worms to your raised garden.
Placing Worms in a Raised Garden Bed
Worms can be very beneficial to most gardens. But, using them in a raised garden bed can take a little planning. Even so, worms are well worth exploring, even if you’re a gardening newbie.
Why You Should Add Worms to a Raised Vegetable Garden
- aerate the soil.
- move water through the soil.
- break up dense, heavy soil with their tunnels.
- speed up the composting process by eating the organic matter in the soil.
- fertilize the soil with their worm castings (worm poop from eating the organic matter), which in turn helps plants grow larger and stronger.
When to Not Use Worms in a Raised Garden Bed
Worms should not be used in elevated raised garden beds, or raised beds with enclosed bottoms. Similarly, they should not be used in raised beds sitting on concrete or any other solid material.
When you put worms into a completely enclosed space it creates several problems.
First, a worm’s skin needs to stay moist because it breathes through its skin. Enclosed garden beds can become too hot and dry for worms, especially during the peak summer months.
Some worms prefer to dig down into the deeper soil. This isn’t possible in beds that sit on or have solid/elevated bottoms.
Lastly, during heavy rains, the soil may become too saturated and the worms may drown.
Which Worms to Use in a Raised Garden Bed
Although you’re probably familiar with big, fat earthworms – like the kind used for fishing – there are actually many types of worms. A lot of worms are beneficial, but some can be invasive and detrimental.
For our purposes, raised bed gardening, the two types of worms most commonly used are red wigglers and nightcrawlers.
Red wigglers (Eisenia fetida), sometimes called red tiger worms, are well-suited for raised garden beds. This type of worm likes to stay nearer the surface, so it won’t dig down too deep. Perfect for a shorter raised bed.
They’re also great composting worms and are most commonly used for this purpose (called vermicomposting). They actually prefer compost to soil. And, of course, munching on all that organic matter produces great fertilizer.
Myth: Cutting a worm in half will not result in two worms. If you do accidentally cut a worm in half and the “head” portion is long enough, it may grow a new tail. Overall, though, it’s best to be careful when digging with any sharp instrument so as not to disturb your worms.
If composting is part of your gardening plans, then red wigglers are definitely ones you want to consider.
Beware though, you’ll find some sellers calling their worms red wigglers, when in fact they’re not. A red wiggler will be a smaller worm, about 2″ – 5″ in length. They’re reddish-brown in color, are striped, and may have a yellowish tint to their tail.
A second good choice for raised vegetable gardens is the good old nightcrawler (Lumbricus terrestris). These guys are much larger worms, potentially reaching lengths of 8 – 10 inches.
Unlike the red wiggler, nightcrawlers don’t usually stick near the surface. They like to burrow deeper into the ground. So if you have a deep bed, or one with more compacted earth, a nightcrawler can be a great choice. With these beds they can get in there and help aerate that dense soil.
Although nightcrawlers eat compost (how much depends on the nightcrawler variety) and provide good fertilizer, their appetites can be less voracious than the red wiggler. They prefer soil to compost material. In addition, they can be more sensitive to different types of soil and temperature fluctuations.
How to Add Worms to Your Raised Garden Bed
Adding worms to your garden bed is not difficult, but there’s more to it than just tossing a pile of worms onto your soil and calling it a day. To properly do their job, worms need to feel comfortable in their environment. Otherwise, they’ll either leave or, worse, they won’t survive.
So let’s talk about finding worms and some of the ways you can add them to your raised beds.
Where Can I Find Worms?
If you’re raised garden bed sits directly on grass or ground soil, over time, worms may simply find their way into your raised bed. Especially if they find the soil in your garden bed appealing.
But, if taking a wait-and-see approach isn’t to your liking, don’t worry. Worms can be purchased commercially at local garden centers and big-box stores, online, or even at bait shops.
A final option is to find worms that are already in your or someone else’s (preferably someone you know!) backyard. If you already have an existing garden spot or compost pile, take a look there first to see if you find worms to transport to your raised bed.
How to Add Worms to Your Raised Garden Bed
Adding by Hand
One of the easiest ways to add worms is to dig several small holes, about 3 – 4 per meter. The holes should roughly be a trowel length in depth.
To learn more about trowels, take a look at my article on the subject. I think you’ll find it helpful.
Once the holes are dug, place a little bit of compost in the bottom. Make sure to moisten the compost. Then add your worms and cover the hole up with soil.
You can also do your own vermicomposting as a way of adding worms to your garden bed.
Vermicomposting is simply the process of using worms to convert organic matter into fertilizer. What’s great about this method is you can actually vermicompost right in your raised garden bed.
To do so, you’ll need a bucket and some food scraps. This article from Growing in the Garden has some great information on vermicomposting in your raised beds.
Tip: If you’re wanting to vermicompost, red wiggler worms would be your best choice. These worms love living in compost and have hearty appetites.
Helping Your Worms Stick Around
Once worms are in your garden bed you want to keep them around. To encourage this, you need to have food for them to eat and an environment they like.
For red wigglers, keep your beds covered with mulch or some other type of organic composting material. They’re voracious eaters, so they’ll welcome this buffet.
Nightcrawlers, on the other hand, like to dig down so it’s important they’re able to access the bottom of your raised garden bed and have the opportunity to crawl into the soil beneath. They also like to eat, so mixing mulch and compost into your soil will help satisfy their appetite.
Since worms breathe through their skin, it’s imperative they’re kept moist and cool. One of the reasons you’ll see them out at night is because it can be too hot during the day and they can become too dry.
For red wigglers, make sure you’re keeping your mulch moist. Take care though not to overwater and drown your worms if you’re vermicomposting,
When using nightcrawlers, mix in some compost a bit deeper into your soil, so they can feed in deeper depths, where they prefer to live.
How Many Worms Should I Add to a Raised Garden Bed?
In general, at a minimum, you should add roughly 5 – 10 worms per square meter.
- Worms can be added to a raised garden bed.
- You should not add worms to beds that are fully enclosed or sit on a solid surface.
- Red wigglers and night crawlers are two of the most popular worms to add to a garden.
- Red wigglers like living in compost and tend to stay near the surface.
- Nightcrawlers like deeper soil and will burrow down.
- Keep your garden bed’s environment inviting to your worms so they’ll stick around and thrive.
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