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Vermicomposting Made Easy: In-Bed Worm Composting

Worm composting directly in the garden bed simplifies the process of vermicomposting. When you use in-bed vermicomposting bins, the worms live, work, reproduce, and make worm castings in the garden bed right where they are needed. 

In-bed vermicomposting solves the problem of what to do with the worms during extremes of hot and cold. For example, vermicomposting in hot weather places (like the low desert of Arizona) is difficult unless you bring the worms inside during the summer months. With in-bed vermicomposting, the worms simply burrow deeper in the beds during the heat of an Arizona summer and then emerge again in the fall. 


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How does vermicomposting work?

Worm composting – also called vermicomposting (‘vermi’ = worm) – is the process of using worms for composting food scraps into vermicompost. Worms eat up to half their weight daily in kitchen scraps, and worm castings are the byproduct of all that eating. Worm castings = GARDEN GOLD!

During digestion, the worms secrete chemicals that break organic matter into nutrition readily available for plants. Worm castings and the chemicals secreted during digestion make up vermicompost.

Vermicomposting Made Easy: In-Bed Worm Composting

What are the benefits of worm composting (vermicomposting)?

  • Vermicompost improves soil texture and structure and aerates the soil
  • Vermicompost increases the water-holding capacity of soil. 
  • The nutrients in vermicompost are immediately available to plants
  • Worm castings contribute to faster plant growth and higher production.
  • Worm castings are dense in microorganisms and nutrients.
  • The chemicals in worm castings help prevent “damping off” and other diseases.
Vermicomposting Made Easy: In-Bed Worm Composting
Worm castings from vermicomposting

What is the easiest way to make and maintain a vermicomposting (worm composting) bin?

A vermicomposting bin built into your raised beds, containers, or in-ground garden bed is the easiest way to make a worm composting bin. 

No need to harvest the worm castings or move the worms inside for extremes of hot and cold temperatures. The worms live, work, reproduce, and make worm castings in the garden bed, right where they are needed. 

Vermicomposting Made Easy: In-Bed Worm Composting
Adding worms to an in-bed worm composting bin

When should I add in-bed vermicomposting bins to my garden beds?

Vermicomposting Made Easy_ In-Bed Worm Composting

If you live in a hot summer climate, do not add worms during the hottest months of the year. In the low desert of Arizona, the best time to add in-bed vermicomposting bins to your garden is from mid-September through May.


Which type of worms should I use for in-bed vermicomposting?

Red wigglers are composting worms that hang out in the top six inches of your garden. “Earthworms” is a generic term for one of the hundreds of varieties of worms. If you dig them from the garden, they won’t stay in the compost level.

That’s not bad, but they won’t hang out in the habitat we set up. Most bait worms need cooler temperatures than Arizona summers. If you buy nightcrawlers, you will probably lose them in June or July. We want all worms. Red wigglers will stay and live better, but no worm is bad.

Purchasing red wiggler worms locally is the best choice. I get my worms from Arizona Worm Farm here in Phoenix. You can also buy them online.


How do I make an in-bed vermicomposter (worm composter)?

Supplies needed for in-bed vermicomposting:

Vermicomposting Made Easy: In-Bed Worm Composting
The 24-sheet shredder I use to shred cardboard for my vermicomposting bins
  • Bin (see options below).
  • Shredded cardboard – This shredder from Amazon will shred cardboard boxes (remove tape and labels first).
  • Kitchen scraps – Perfect worm food includes bananas, watermelon, pumpkin, strawberries, apples, and more. I keep them on the counter in this container until I add them to the bins.
  • Worms – Red wigglers are preferred. I get mine from Arizona Worm Farm. Look for a local supplier if possible. If you can’t find one you can get them online here. The earthworms typically found in the garden aren’t suitable for vermicomposting.

Bin options for in-bed vermicomposting:

The bin helps designate a place in your garden for the worms to go. Choose one slightly smaller than the depth of your garden bed. There are several options:

Vermicomposting Made Easy: In-Bed Worm Composting

Vermicomposting Made Easy: In-Bed Worm Composting
  • A wire garbage can with wide openings is the simplest way to add bins to your beds. They are available at Dollar Tree or Amazon.
  • Lifting the bin out of the bed is simple when it’s time to collect the finished worm castings.

Vermicomposting Made Easy: In-Bed Worm Composting
  • Shape hardware cloth into a cylinder slightly shorter than the depth of your garden bed.
  • Wire the ends of the hardware cloth together.

Vermicomposting Made Easy: In-Bed Worm Composting
  • 2-gallon bucket (with the bottom removed and holes drilled in the sides)
  • I used this drill bit (for drilling holes) and a Dremel (to cut off the bottom of the bucket).
  • If you use this type of vermicomposting bin, it is STRONGLY RECOMMENDED to remove the bottom of the bucket.

Directions for installing and using an in-bed vermicomposting bin:

Vermicomposting Made Easy: In-Bed Worm Composting

1. Dig a hole in the garden bed the bin size.

Place the bin in the hole

2. Place the bin in the hole.

Fill the habitat with shredded cardboard, and wet it down. Allow cardboard to absorb moisture overnight.

3. Fill the habitat with shredded cardboard, and wet it down. Allow cardboard to absorb moisture overnight.

Add 300-600 red wiggler worms to the worm habitat.

4. Add 300-600 red wiggler worms. Red wigglers are preferred. I get mine from Arizona Worm Farm. Look for a local supplier if possible. If you can’t find one you can get them online here.

Begin feeding worms - see worm feeding details below.

5. Begin feeding worms – see worm feeding details below.

Cover the food scraps with a layer of "brown" materials. Examples: wood chips, dried leaves, soil, shredded cardboard

6. Cover the food scraps with a layer of “brown” materials. Examples: wood chips, dried leaves, soil, and shredded cardboard.

Cover the worm habitat. I use a tile. They are very inexpensive and the right size for my habitat. You could also use a piece of wood. If you are using a bucket, the bucket lid works well.

7. Cover the worm habitat. Use a thick layer of wood chips. You could also use a piece of wood or a tile. If you are using a bucket, the bucket lid works well.

Check back occasionally and add more food scraps. (Always top with brown). Remove any large pieces of uneaten food.

8. Check back occasionally and add more food scraps. (Always top with browns). Remove any large pieces of uneaten food.

When food scraps are gone and the bucket is empty, you can harvest the castings. (The worms will leave the bucket and be in the bed). Spread the castings around the garden bed. You can also leave the castings in place.

9. When food scraps are gone, and the bucket is empty, you can harvest the castings. (The worms will leave the bucket and migrate to other areas of the bed). Spread the castings around the garden bed. You can also leave the castings in place.

Begin the process over again, starting with fresh shredded cardboard, food scraps, and brown. No need to add additional worms.

10. Begin the process over again, starting with fresh shredded cardboard, food scraps, and browns—no need to add additional worms.


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How many in-bed vermicomposting bins should you have?

I have one worm habitat in each bed. One habitat per bed is enough to get a continuous flow of microbes.

You can add as many bins as you need to process your food scraps and waste, but you don’t need a high density of worms for a successful garden.

Add at least 300 worms for each habitat. 600-800 is better, if possible.

Worms multiply to fit the space and available food. In a big garden, worms will breed faster.


What do worms eat?

Perfect worm food: Watermelon, bananas, sweet potatoes, pumpkin, strawberries, apples, beans, pears, carrots, cherries, grapes, peaches, spinach, cucumbers, cabbage, celery, mangoes, tomatoes, corn, cardboard, shredded paper and egg cartons.

Feed worms in moderation: Bread, potatoes, pasta, rice and other starchy foods

Avoid feeding worms: Citrus, meats, bones, eggs (crushed shells are ok), dairy products, processed foods, salty or greasy food, and pet waste.

Tips for feeding worms in vermicomposting bins

Tips for feeding worms:

Tips for feeding worms in vermicomposting bins

Add equal amounts of greens and browns each time you feed.

  • Make sure worms have eaten previously added food scraps before adding more. Plan on feeding worms about once per week.
  • Cut or blend food before adding to bins. Smaller pieces of food break down faster and speed up the composting process. 
  • Cover with browns after adding food scraps (greens) to avoid attracting fruit flies
  • Remove large pieces of uneaten food. Pay attention to what the worms are eating and not eating. 
  • The bin’s interior should have the moisture consistency of a wrung-out sponge (damp but not overly wet). Spray lightly with a hose if necessary.
  • Cover with a thick layer of wood chips, or replace the lid on the bucket after feeding. 
In-bed vermicomposting bins built into your garden simplifies worm composting. The worms live & make worm castings right in the garden beds.


Frequently asked questions about in-bed vermicomposting:


Question: I have a ton of black soldier fly larvae in both of my bins. Will they be detrimental to my red wigglers?

Answer: Black soldier flies are unusual in the Phoenix metro area because it is so dry here. They won’t hurt the worms, and within two or three weeks, they pupate into harmless flies (the live fly has no mouth – the only stage of the insect that eats is the larvae) that die within a day or two.  

The larvae are voracious eaters, so someone who finds them in the bin should feed much more than normal. If they put buckets or bins in the ground like your setup, they may observe fewer worms in their bucket or bin as the worms will move away from the heat the larvae produce.  

The worms are fine and will return when the larvae leave. The larvae don’t bite – if someone wanted to remove them (easiest is with a kitchen strainer) and toss them, that is a fine option too.


Question: I dug into two of the buckets to see how my worms were doing, and they were missing. Not a worm to be found in either bucket. Would you expect the worms to stay in that bucket full of compost, or have they perhaps left their original home and crawled around through the rest of my garden, maybe just coming back to the bucket for their meals?

Answer: The worms go through the beds, and some are in the buckets with the scraps. I’m guessing with the intense heat we are having, they are burrowing down as deep as they can go.


in-bed vermicomposting
Adding fresh shredded cardboard after emptying the bucket of the worm castings. The worms will return to the bins.

Question: I have two guinea pigs, and feed them alfalfa hay, organic alfalfa pellets, and leafy greens such as romaine lettuce, spinach, swiss chard, and parsley. They produce a lot of waste (approximately 1 quart of waste hay and pellets daily). I read that I can add their waste and their waste hay directly to my raised bed gardens, which I have been doing and have been digging it in with a hand spade. Will red wiggler worms compost the guinea pig waste and waste hay?

Answer: Red wigglers will eat guinea pig manure as it decomposes – and they will not eat anything that they don’t like until it decomposes enough for them to eat. A pound of worms will eat about a pound of waste a week. You will likely produce a lot more than that, but that’s not harmful either. The worms will eat what they want, and the rest will feed your beds as it has.  Your current process will probably produce good results – the worms will improve it.


in-bed vermicomposting
Full bin of food and castings. Let the worms complete the food before harvesting the castings.

More frequently asked questions about in-bed vermicomposting:


Question: How often do you add water to the compost buckets in Arizona heat?

Answer: The beds get watered 2-3 times a week during the summer and about once a week in the winter. The buckets are in the middle of one of the watering grids in my beds, and get watered as well.


Question: Can you add chicken poop to the buckets?

Answer: You can, in small amounts. Too much will overwhelm the worms. Just mix the poop with bedding (anything that was a tree…leaves or shredded cardboard or mulch) and they will do great.


Question: Do the finished castings seep into the garden through the holes in the bucket or does it need to be scooped out?

Answer: Both. It is carried out of the bed by the worms movement. When the worms have completed the food scraps you can also scoop the castings out and spread them around the bed. You then begin the process again, adding fresh cardboard and food scraps. The worms will come back into the bin. 


in-bed vermicomposting
Red wiggler worms are perfect for in-bed worm composting.

More frequently asked questions about in-bed vermicomposting:


Question: How do the in-bed vermicomposting worms do during the summer? Is there anything special you do to keep them cool during Arizona summers so they don’t die?

Answer: They burrow down into the beds and look for cool spots to stay cool. In-bed worm composting in Arizona is a great option for our hot summers. Beds should be at least 12 inches deep. 


Question: Do you ever have problems with ants attacking the worms in the in-bed vermicomposting bins? 

Answer: Ants don’t generally attack worms. By making the area more moist, you can discourage ants and make the habitat better for the worms. You can use these ant bait traps


Question: Will in-bed vermicomposting work in containers?

Answer: Generally, it will work fine. The challenge with worms in pots for most people is that they tend to let plants get root bound and there is less soil than the worms like. As long as you have organic material and space for them to move, they will do great. You don’t need to bury a bin in the container. You can do the same thing if you just dig out a hole and put a lid on the hole.


in-bed vermicomposting

More frequently asked questions about in-bed vermicomposting:


Question: Can worms eat bokashi compost?

Answer: Absolutely. Done right, bokashi produces lots of microbes and breaks down waste to make it easier for the worms to consume.


Question: My bed is raised completely off the ground, due to the previous owner PLANTING Bermuda grass (sigh). I’ve been reading that these sorts of beds are not a good home for worms since they may get too hot or drown. We are in Arkansas, so it doesn’t typically get above 100. The bed has good drainage, and a soil depth of about 10″. Do you think worms would be OK to add or no?

Answer: We never worry about drowning worms. They will find dry places to hang out. If she can grow vegetables, the worms will be fine. Fully-raised beds (off the ground) do tend to get hot. She should shade it in the summer, but they will probably be fine. The worst thing that might happen is they die over the summer and she has to add more in September when they start getting cooler nights.


Question: Will chemical fertilizers hurt the worms?  

Answer: In small amounts, probably not, but direct contact or a large amount could. The whole idea of worms is to let them convert organic materials into a natural source of nitrogen. The worms should reduce or eliminate the need for inorganic fertilizers. Chemical fertilizers such as inorganic nitrate salt will reduce the pH, but they also kill some of the microbes we like.


in-bed vermicomposting
Spreading worm castings around a raised bed garden.

More frequently asked questions about in-bed vermicomposting:


Question: Can I use earthworms or do I need to use red wrigglers for in-bed vermicomposting?  

Answer: Red wigglers are composting worms that hang out in the top six inches of your garden. “Earthworms” is a generic term for one of hundreds of varieties of worms. If you dig them from the garden, they won’t stay in the compost level. That’s not bad, but they won’t hang out in the habitat we set up. Most bait worms need cooler temperatures than Arizona summers. If you are buying night crawlers, you will probably lose them in June or July. We want all worms. Red wigglers will stay and live better, but no worm is bad.


Question: Are red wigglers native?

Answer: Red Wigglers are not native to the US – No worm is- they were all killed off during the Ice Age. But, Reds are not considered invasive. Especially in Arizona. They stay where they are at and can’t live in our natural native soils.


Question: Is cardboard toxic?

In our world, it is hard to avoid all chemicals. Cardboard is the most heavily used packaging material, and feeding it to our plants and trees is the best way to make use of a very valuable resource. The benefits of feeding it to our worms (and then our plants) dramatically outweigh any other option. If it’s painted with colored ink from overseas, it is very remotely possible that it has toxic heavy metals. Almost all the inks used in the US (something like 99.3%) are made from soybean oil and are completely harmless. It is also possible (but not likely) that the adhesives include formaldehyde. But, Formaldehyde also occurs naturally in the soil. It is produced during the decay of plant material in levels considered safe.


Question: Can I feed my vermicomposting worms bread?  

Answer: Yes. Grain-based items are fine (i.e., crackers, cooked rice, pizza crust, and bread). 


Question: What do I do about cockroaches in my bins?  

Answer: Cockroaches can be hard to eliminate completely, but the best bet is to aggressively cover the food waste with browns. Adding at least an inch of browns on top will help. 


How to Compost: 10 Simple Steps for Composting Success

Want more information about composting? This article shares 10 simple steps to get you started. 


If you enjoyed this post about in-bed vermicomposting, please share it:


Karen

Tuesday 26th of March 2024

How well will the worms overwinter in an in ground container? We can easily get to -30 Celsius or colder (zone 3) so what if anything would I have to do to ensure the red wrigglers survive?

Angela Judd

Thursday 4th of April 2024

I checked with Zach at the Worm Farm and here is his response: "Hard, hard freezes are a bit problematic. Best move is to SERIOUSLY cover the worm bin with fresh waste as it starts to get close to freezing . Preferably fresh manure, but any kind of green waste works.10-12 inches. More if they have room. Then add six inches of brown. Water well. It will heat and the worms will be fine until spring. They want to absolutely not touch it during winter."

Treena

Sunday 10th of March 2024

I have a Lomi composter and I put the compost in my garden beds. Would you recommend I also get red wriggler worms to put in the garden beds too?

Angela Judd

Sunday 10th of March 2024

Although the Lomi does break down the waste, unfortunately there are no microbes - it's dry, mostly dead soil. It will add organic matter, but no microbes to your soil. If you have garden beds putting your food scraps in the beds with red wigglers would add beneficial microbes and improve your soil fertility.

Dan Subaitis

Wednesday 15th of November 2023

Do rats pose a problem for vermicomposting?

Angela Judd

Tuesday 21st of November 2023

Hasn't been an issue. Keep things well covered with browns.

Scott

Monday 30th of October 2023

We have bunnies. They eat dried pellets, spring mix, spinach and hay. In their litter bins we use shredded paper along with hay. Can I include the paper and their droppings in the vermicompost holes as part of the brown material?

Angela Judd

Wednesday 1st of November 2023

Sure. In small amounts. You don't want to overwhelm the worms.

Pamela Fair

Sunday 22nd of October 2023

Will "beneficial" nematodes kill the worms? I've Heard of only using nematodes to water seed starts then they are "inoculated" Others treat the bed. Either way will they kill the worms in the vermicomposting? Love your site.

Angela Judd

Tuesday 24th of October 2023

No, worms love eating nematodes.