Generally speaking, adding worms in a raised bed garden isn’t necessary. That’s because the little crawlies will find their way to your garden regardless.
However, it could take some time for them to make their way to the bed if it was only recently set up. So, how do you expedite their arrival?
Today, we’ll talk about all things worms, including the best worms for raised garden beds and their benefits so you can grow a prosperous raised garden bed.
Why Are Worms Necessary in a Raised Garden Bed?
Often called topsoil physicians, the worms' activities in soils are known to have many benefits. Among them are:
1. Boost Nutrients
Worms aid in the decomposition of dead leaves, roots, and other plant debris. Compared to the soil around them, casts of worms are richer in nutrients and have readily available nitrogen, which plants can use.
Also, research shows that worm casts have nearly four times more phosphorus than surface soil. Worms burrow and leave tunnels filled with nutrient-rich casts for plants to take advantage of.
Roots come in contact with these casts, aiding their growth. Thanks to these casts, roots can spread farther and deeper in the soil to access additional nutrients and moisture.
2. Improve Drainage
Old soil in a raised bed garden is more compact and could use some loosening up. Worms can do that for you in the best way. They can channel and burrow to soften the soil, allowing more air and moisture to pass through it.
3. Strengthen the Soil
A prosperous raised bed garden relies so much on soil structure. With good soil structure, plants can absorb more moisture.
Worm casts act like cement, strengthening the bond between soil particles to create aggregates. These aggregates add architectural integrity to the soil, ensuring its structure is as solid as ever.
Apart from that, aggregates store moisture exceptionally well. When worms leave their casts on topsoil, they form aggregates that add compactness to the surface and keep your plants safely in place.
4. Boost Productivity
With the improvement of nutrient availability, soil structure, and drainage comes the enhancement of overall productivity. Worm casting is essential to plants, especially plants in raised garden beds. All you need are a few grams of worm casts to make a difference.
Best Worms for Raised Garden Beds
Keep in mind that not all worms are ideal for gardens; in fact, some of them may be bad for your gardens. They won’t loosen up the soil properly and, thus, fail to achieve any of the above goals for your raised bed garden.
These types of worms make the soil compact, which would be a bad thing. So, you’ll want to find out more about these worms before introducing them to your garden.
So, what are good worm species to add to your raised bed garden? Let’s have a look at eight of them that experts recommend and we’ve also tried and tested.
1. Lumbricus terrestris
These are anecic worms, which are the largest earthworm species in the world. Their size range is from 20 to 25 centimeters, and you can find them in all parts of the globe.
Often called the common earthworm or lobworm, Lumbricus terrestris typically feeds on dead plant leaves, though they may also acquire nutrients from feces or decomposing insects.
These worms burrow deep and usually only head to the surface to feed. They partially digest dead insects or plant leaves in their mouth before they swallow them.
2. Lumbricus rubellus
Also called red earthworms, Lumbricus rubellus are smooth, reddish species with semi-translucent segments that measure 25 to 105 millimeters in body length.
They are especially active in organic-rich soil. They also thrive in high moisture soil, as it provides them with what they need for gas exchange. These worms feed mostly on decomposing organic matter.
In doing so, they improve the rate of matter transfer across every trophic level and make it easier for crops to absorb nutrients
3. Allolobophora caliginosa
More commonly known as gray worms, Allolobophora caliginosa are worms native to Great Britain with three distinct color shades in the front. They measure six centimeters when motionless and are found mostly on topsoil burrows where they feed on organic matter.
4. Eisenia fetida
These worms are known by many names: redworms, tiger worms, trout worms, red wiggler worms, red Californian earthworms, panfish worms, and more. They handle compost, manure, and rotting vegetables the best.
That’s why they are used widely to decay domestic and industrial waste. They were previously native to Europe but are now grown in all parts of the world and used in flushless toilet systems.
5. Eisenia hortensis
European nightcrawlers are medium-size worms with bluish-colored bodies that grow to an adult weight of around 1.5 grams. You'll often find them in organic-matter-rich garden soil and deep woodland soil.
They thrive best in medium soil with a higher-than-usual carbon to nitrogen ratio. That's because it is similar to the environment in compost pits, where these worms also perform very well.
6. Perionyx excavatus
These composting worms, known as Indian blue or blue, are produced commercially. They are widely popular in the industry due to their ability to produce worm castings quickly. These worms are ideal for gardens in tropical or subtropical regions.
Perionyx excavatus can grow to about one to three inches and have two different colors. Its body is usually reddish-brown, and its head is purple.
7. Amynthas gracilis
These pink- or brown-colored worms can reach four to six inches in length and thrive in warm weather. Their presence boosts soil porosity and improves the water circulation in the soil, which in turn will benefit your plants.
8. Eudrilus eugeniae
African nightcrawlers used to be native to the tropical regions of West Africa, but they are now found across the warm regions of the globe.
They can grow up to 10 inches in length and 2.5 grams in weight after just two months. They perform best when the temperature is 50 degrees.
How to Introduce Worms to Your Raised Garden Bed
Now that you know what kind of worms to add to your garden, how do you start adding them? Ideally, worm introduction should start in spring. Follow these steps to ensure you get the process right:
- Purchase one to two pounds of cornmeal and sprinkle them on your raised bed garden.
- Using a shovel, mix the parts of the soil with the cornmeal with the topsoil.
- Water the area to maintain high moisture levels. Don’t make it too wet; otherwise, you could foil the plan.
- Bacteria will start to grow in the area after a month, which aids in worm activity. Over this period, add one pound of cornmeal every 14 days. You may use manure or compost to boost soil nutrients, if not cornmeal.
You can also try these steps for attracting earthworms to your garden:
- Purchase a bag of organic manure and slit the bag’s belly. Find a shady area and place the bag there, slit-side down.
- Do this in the fall, and your manure bag should be full of worms and offspring come spring. Add these to your compost-filled raised garden bed, and voila! You’re all done.
How to Care for Your Worms
Worms are diet and environment-sensitive, so it’s vital to care for them particularly well on these two fronts. Here’s what you need to do:
1. Add Manure or Compost
You may think that a large bucket of worms can solve all your problems, but there’s more to vermiculture. Though that should increase castings production, your worms can die or slither away.
To keep worms in your raised garden bed, you will need to introduce manure or compost. In that way, you keep your worms healthy and working.
2. Get the Heat and Moisture Right
Worms love warm soil. They perform best in all aspects when the temperature is warmer than when it is cooler.
That said, you should always start their garden introduction during springtime when the soil temperature is between the ideal range of 15 to 30 degrees Celsius and the ground has just the right amount of moisture.
3. Till Less
Tilling is great for the soil, but too much of it can harm your worms. Till less frequently, as you have the worms for that.
Also, tilling could often result in fewer worms, as you may cut most of them into pieces. No, worms cannot regrow after you split them.
Instead of tilling, add more compost or manure. You make the soil healthier and spare your worms from getting chopped into pieces.
The Right Worms Are Great for Your Raised Bed Garden!
Using the right worms can improve your raised garden bed in numerous aspects. They can boost aeration, provide nutrients, and improve solid amendment, and porosity.
However, be careful with the worm selection process since some species can do more harm than good. They can end up doing the opposite of what you’re trying to achieve and spell the end for your garden before it even begins.
Our list of the best worms for raised garden beds is the ideal place to start when you want to take this route.