Something we’ve hammered home repeatedly in our worm composting articles is the importance of bedding (and the other main safe habitat material - “living material”). These substrates help to balance the moisture and C:N, provide a refuge for the worms, and can help to discourage the establishment of various pest organisms.
Loose bedding, such as shredded cardboard and coco coir has been the gold standard for many years - but more recently, a new bedding player has emerged in the form of worm bin blankets (often referred to simply as “worm blankets”).
Worm blankets offer more of a uniform, seamless - but still very breathable - biodegradable cover in a worm composting system. Our recommendation is to use them directly over the main worm composting zone, in conjunction with a thick layer of loose cover bedding (kept over top). This provides a one-two punch of moisture-retention and pest-prevention, helping to ensure that your bin is much better protected than it would be with lots of loose bedding alone.
Likely the most popular worm blankets on the market are those made from jute or coir - both quite solid in construction and slow to break down. As a long-lasting physical barrier that still allows plenty of airflow, these can be a great choice - but they don’t necessarily add much value to the habitat itself, at least not for quite some time. There have also been some reports of worms ending up trapped in the mat fibres. This may not be something the average vermicomposter will need to be overly concerned about, but it’s still worth keeping in mind. One other potential downside of jute and coir mats is that they are imported from locations outside of North America, so the environmental footprint is something to consider as well.
As the title of this article suggests, our vermicomposting blankets of choice are hemp blankets - a distinctly different option, with its own set of pros and cons!
PROS
Less expensive - It’s not uncommon for jute or coir worm blankets to be $10-$20 each. As a comparison, our hemp blankets can be purchased for as little as $3 each when purchased in packs of 5 (at the time of writing).
Great multi-use potential - Apart from use in a worm composting system, there are a variety of possible uses for these hemp blankets, such as grow mats for microgreens (we’ll circle back to this further along).
Made in Canada - These days, supporting Canadian businesses is even more important! Canadian residents can also rest easy knowing the environmental footprint is smaller than for blankets sourced from overseas.
Worm habitat enhancement - Hemp fibres decompose more quickly than jute or coir, meaning these mats get integrated with the worms’ habitat a lot more quickly. This makes them more beneficial as a bedding/habitat material that helps to balance out deposits of rich food materials. If you really want to have fun with hemp blankets, we have some different ideas you can test out (described further along) as well.
CONS
Fragment more easily - Gentle handling is recommended, since the hemp fibres can drop away from these mats quite readily, especially when shaken or bumped. Not a major issue - just something to keep in mind before adding them to a worm bin.
Don’t last nearly as long as popular choices - As touched on, the hemp fibres in these blankets tend to break down more readily than either jute or coir. While this makes them great for worm habitat enhancement, it also means they won’t offer the same system protection over a longer period of time, the way jute and coir mats can.
Not as widely available - The hemp industry is still relatively small and new, so there likely aren’t many suppliers offering hemp blankets at this time. It’s no secret that we have them, though! ☺️
Helpful Hemp Blanket Tips & Info
Careful Handling - We’ve already touched on the somewhat-fragile nature of these blankets. We recommend trying to minimize the amount of handling prior to use, just so you don’t end up with a lot of hemp dust and small fragments outside of your bin.
Cutting Hemp Blankets - Depending on the dimensions of your bin (or your intended use), you may need to cut your hemp blankets to an appropriate size. Fairly heavy duty (and sharp) scissors or shears can work, as can box cutters. If you want to get really serious about it, we recommend some form of electric cardboard/textile cutter, such as this one from Amazon (which could help you break down boxes for bedding as well).
Best Location - We always recommend keeping a nice thick layer of loose cover bedding (eg shredded cardboard) in a vermicomposting system. If you plan to use a worm blanket, we suggest placing it just below this cover bedding, and just above the main worm zone (i.e. active composting zone). You can then add your food deposits directly below the blanket - just remember, moderation is always important.
The White Coating - Some people will naturally wonder about the white underside of our hemp worm blankets. This is a wood-based cellulosic sheet used to add structural stability to the mats. It is of course completely biodegradable and safe!
Fun Hemp Blanket Ideas
Our recommended use for hemp worm blankets is a great starting place - and all you need if you want to keep things simple - but we also like to encourage people to think a little bit more “outside the bin” from time to time. 😉
So, here are a few additional ideas to (hopefully) get our readers inspired!
Mats for Growing Microgreens
The fibres in hemp blankets are perfectly suited for seed germination and the growth of microgreens (and plants in general). Cut in half, you’ll end up with two mats that fit fairly well into a standard 10” x 20” seedling grow tray. We’ve been testing them out this way, and have been really impressed with the results!
NOTE: we did somewhat smaller trays, though.
Here are the sunflower, speckled pea and radish seeds we tested…
…and the beautiful greens we ended up with (NOTE: the sunflowers and radishes are on the opposite sides from the previous image)!
And look at that healthy root growth!
What’s great for microgreens-growing composters is that once you are done with your flat of greens, you can toss the leftover mat in your composting systems, where all the plant stubble and roots (and mat itself) will become food for a variety of organisms. They are especially well-suited for vermicomposting systems, with the worms usually crowding in and breaking them down quite quickly!
We tossed some in our “Mama CFT” system and it didn’t take long before we found loads of Red Worms directly underneath - even right into the fibres of the mats..
NOTE: There are two possibilities for the orientation of your used mats. You can add them plant-stubble side down to discourage any further growth, and increase the likelihood of them breaking down more quickly. Alternatively - especially if the system gets some light - you may want to add them plant-side-up, to allow for a bit more growth (in an enclosed worm bin, this can provide you with a bit more of a long-term food source).
We will be exploring the possibilities on this front even further in the weeks and months - so do stay tuned!
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Hemp Food Rolls
A somewhat different way to put your hemp blankets to good use in your systems is in the form of hemp “food rolls”. You can think of it as the ultimate jumbo burrito for your worms! 🙂
This method is especially well-suited for those who want a bit more of a hands-free approach - and you may in fact want to set up a separate (perhaps smaller) passive vermicomposting system solely for this purpose.
To illustrate the concept, we decided to set up our own dedicated hemp food roll bin! We chose a small, dedicated bin for this purpose - a 5 gal HDX bin from Home Depot.
Step #1 involved making the roll itself. Ideally, you will want to have some frozen-then-thawed, or well-aged compostable kitchen scraps ready to go, along with some form of living material. We recommend building the roll in a shallow plastic tub or tray, such as a plastic mortar mixing tray, so as to reduce the potential mess.
Once the blanket is laid out along the bottom of your vessel, it’s time to start building your food waste burrito!
Starting with living material (LM), if you have it, is recommended. We happened to have a nicely aged mix of mulched fall leaves + grass clippings that was loaded with life.
Although not mandatory, if you happen to have some rock dust or some of our pH Buffer Grit, you may want to sprinkle some in (where in the layers you add it doesn’t really matter).
Since our leaf mulch mix was on the dry side, we decided to give it a good spray down before moving to the next step. Aged (dechlorinated) tap water or rain water would be great for this - but we opted for a 100:1 Water:EM mix just to help boost the microbial activity even more!
Next, it was time to add our main “filling” - some well-aged kitchen scraps that had been left outdoors (in sub-zero winter weather) and then allowed to warm up again.
Before rolling this puppy up, we wanted to inject some more microbial goodness with another layer of our leaf mulch mix! These LM layers, in addition to the hemp blanket itself, offer the perfect way to help balance out all that food waste (NOTE: this is a lot more food waste than we would typically recommend for a single feeding in a small to medium sized indoor worm bin, just so you know).
The roll likely could have simply been placed in the bin at this point, but who are we kidding - we’re “safe habitat” fanatics! So, we went the extra mile by adding a thick “false bottom” of scrunched up, heavy duty kraft paper down below. This will help to soak up all the liquid draining down from the roll, and should eventually be a really nice worm habitat zone.
Nothing fancy about adding the roll - it was just plopped down on top of the false bottom.
NOTE: Be a bit careful with your rolls. They can tear a bit when wet and really loaded up with waste materials!
Our approach with this particular test system was super-simple. All we did to finish it up was fill in the remaining space with more of our leaf mulch mix. You could just as easily add a regular bedding material like shredded cardboard.
What we wouldn’t recommend doing, though, is adding any additional food materials. The roll itself has more than enough to keep this system going for a while!
OK, so there was one more very important step. We obviously needed to add some composting worms! With all this leaf litter involved, we decided a worms + isopods mix (something we’ll be writing more about) would work best. We simply transferred some worm- and isopod-rich material from another active system.
Initially, we added the regular HDX lid to finish things off - but later decided to switch it out for a loose plastic bag cover. This provides us with even more airflow (helpful when working with isopods).
As alluded to, this type of system works very well with a “set-it-forget-it” type of approach. Our compost workers have everything they need to keep them going for a while! The only thing we’ve done since setting up the bin in late January is top up the leaf mulch mix.
Stay tuned for future system updates!
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Blanket Stacks
This one is somewhat similar to the food roll idea, but instead of rolling a single blanket up (with all the goodies inside), you can make layers using multiple blankets. In smaller bins you could fold a single blanket in half, effectively creating double the layers. In larger systems you could lay them out flat.
You can use the same basic set-up protocol as with the food rolls. Over top of each layer you can add some living material and compostable food scraps - and of course, we recommend adding a final, thick layer of loose cover bedding over top of everything as well.
If you wanted to get really adventurous, you might even try this in an open system with light shining over top (or sitting in a sunny spot in your house), and make a sort of indoor “lasagna garden” with herbs or other plants growing in it. The worms will absolutely love all those layers, and the plants should thrive too!
Final Thoughts
Hemp blankets offer a great (and relatively inexpensive) way to boost your pest protection efforts and improve worm habitat in your vermicomposting systems. They are unique (compared to other worm blankets) in that they break down quite quickly, so you may want to double up, or at least keep a supply of them on hand for ongoing use.
Apart from using them in your worm bins, you may also want to test them out for growing microgreens and other plants - or in other creative ways.
We’d love to hear from you about the different ways you are putting your hemp blankets to use!
Helpful Related Articles
How to Feed Your Worms to Get The Best Results From Your Worm Bin
Smelly Worm Bins - Possible Causes & Effective Solutions
What Is “Living Material”?
Bedding - The Most Important Material in Your Worm Bin?
Recommended Products
Hemp Worm Blanket
Urban Worm Bag (Hemp blankets are almost perfectly sized for this system)
Red Wigglers
Worm Starter Kit
Worm Rake
pH Buffer Grit
BioChar