Can You Compost Rhubarb Leaves – How To Compost Rhubarb Leaves


By: Amy Grant

Love your rhubarb? Then you probably grow your own. If so, then you probably know that while the stalks are edible, the leaves are poisonous. So what happens if you put rhubarb leaves in compost piles? Is composting rhubarb leaves okay? Read on to find out if you can compost rhubarb leaves and if so, how to compost rhubarb leaves.

Can You Compost Rhubarb Leaves?

Rhubarb resides in the genus Rheum, in the family Polygonaceae and is an herbaceous perennial plant that grows from short, thick rhizomes. It is easily identified by its large, triangular leaves and long, fleshy petioles or stalks that are green at first, gradually turning a striking red in color.

Rhubarb is actually a vegetable that is primarily grown and used as a fruit in pies, sauces and other desserts. Also referred to as the “Pie Plant,” rhubarb contains vitamin A, potassium and calcium – as much calcium as a glass of milk! It is also low in calories and fat, and is cholesterol free and high in fiber.

Nutritious it may be, but the leaves of the plant contain oxalic acid and are toxic. So is it okay to add rhubarb leaves into compost piles?

How to Compost Rhubarb Leaves

Yes, composting rhubarb leaves is perfectly safe. Although the leaves contain significant oxalic acid, the acid is broken down and diluted fairly quickly during the decomposition process. In fact, even if your entire compost pile was made up of rhubarb leaves and stalks, the resulting compost will be much akin to any other compost.

Of course, initially, prior to the microbial action of composting, rhubarb leaves in compost piles would still be toxic, so keep the pets and kids out. That said, I’m guessing that’s pretty much a rule of thumb anyway – keeping the kids and pets out of the compost, that is.

Once the rhubarb starts to break down into compost, however, there will be no adverse effects from utilizing it just as you would any other compost. Even if one of the kids got into it, ahem, they would suffer no ill effects except a scolding from Mom or Dad. So go ahead and add rhubarb leaves to the compost pile, just as you would any other yard debris.

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Rhubarb doesn't have a lot of insect pests, but the two most common ones are rhubarb curculio, or rusty snout beetle, and slugs. Black spots on the stems of the plants indicate rhubarb curcolio jagged holes indicate slug or snail activity. Control the beetles with rotenone or pick them off by hand. Set out slug traps if slugs are destroying the rhubarb.

  • Rhubarb stalks contain oxalic acid, which is toxic when eaten in large amounts.
  • Most animals avoid rhubarb, but hungry animals will eat almost anything.

Composting Leaves 101 – The Basics

When it comes to composting leaves, following a few simple guidelines will go a long way towards creating a compost pile that decomposes quickly, and is filled with the right blend of nutrients.

In most cases, a well-made pile this fall will be ready for use in the garden by late next spring.

Here are some top tips for creating a great compost pile this fall with leaves:

Select The Right Leaves

Although nearly all leaves can be composted, there are some varieties that are harder to compost than others.

Maple leaves are among the best to compost

Leaves from trees that produce waxy leaves or needles, such as magnolia and pine trees, are among the hardest to compost. Their protective coating can take years to break down.

These leaves are great for using as a mulch, but are best left out of the compost pile. Especially if you are looking to have a pile ready to use next spring or summer.

So what are the best leaves to use? Fruit trees, maple trees, and other soft-leaf producing trees such as ash, birch and beech top the list.

The leaves from these trees break down quickly in a compost pile. At the same time, they provide a good balance of nutrients to the pile.

Oak leaves can be use for composting too, but due to their acidity, should never make up more than a third of the pile.

Creating The Pile – Shred Those Leaves!

If you want to make compost fast with leaves – you need to shred them. It speeds up the decomposition process immensely – and saves on space!

Shredding leaves before adding them to the pile is a must!

Whole leaves can take years to break down, and create a wet, moldy and unsightly compost pile.

Shred leaves into fine pieces with either a leaf shredder or a lawn mower. A bagging attachment on a push mower will make quick work of the shredding process.

Adding Power To Your Pile

Although large piles of shredded leaves will decompose slowly over time by themselves, by adding additional “hot ingredients” to your pile, you can speed up the process and create your own version of black gold.

A great compost pile is made up of a blend of dry and green materials. The shredded leaves (a dry material), need to be blended with enough green to activate the pile.

Compost is a gardener’s best friend

Green materials are the main source of nitrogen to the pile. And nitrogen is the crucial element needed to start the process of rapid decomposition.

A good rule of thumb for a fast-acting pile is to add one part green for every four parts dry. In simple terms, that means if you add in four large bags of shredded leaves, add in the equivalent of a large bag of green material.

The green family is made up of items like coffee grounds, potato peels, vegetable scraps, and green grass clippings. Also included in the green family is manure from animals like chickens, rabbits, cow or horse. (Do not use pet manure as they can easily transmit disease)

All of these materials can be added to your shredded leaf pile to create the perfect fall compost pile.

Composting Leaves – Don’t Forget To Turn And Water That Pile!

Once created, a compost pile needs oxygen and water to thrive.

And the only way to provide it is by turning and watering the pile as needed on a regular basis.

Compost piles need to be turned a few times each week for maximum success. This process brings oxygen back into the center of the pile, and keeps the decomposition process going strong.

Fall’s leaves are more than just beautiful – they are perfect for making compost!

Like oxygen, a compost piles needs moisture to stay active as well. A working compost pile should be moist, but not saturated.

If your pile begins to dry out in the center, add water when turning to help keep it active.

For more on creating great compost, check out our page dedicated to creating black gold : TIMG Composting Articles

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How to Compost Leaves

If my mention of the desired sponge-like texture has you scratching your head, perhaps it’s time to brush up on your composting basics? If so, we have an article to help you with that.

Go ahead and give it a read. I’ll wait!

In this article, I’m going to provide you with a primer on how to compost with leaves.

Ratios

Does that word give you the creeps? Make you want to click away? Don’t worry, math is not my favorite subject either, so I’m going to dumb this ratio thing way down for you.

All composting instructions will likely mention that a certain ratio of browns to greens – i.e. the proportion of carbon-heavy materials to nitrogen-heavy materials – should be respected.

The best and most user-friendly advice on this subject that I have encountered is pretty simple: aim for twice the volume of browns to greens.

This is the proportion I use in my own piles, and it works great for me.

What does this mean? If you have a pail full of kitchen scraps, spread it out on your pile, and cover it with two pails full of dead leaves.

Water your pile after this, and if the food scraps are showing through, cover them with more leaves.

That’s it. Or that can be it, if you already have a bin or pile going, and just want to start adding some leaves to it.

However, if you’re just starting out or want to start a new bin to add to your collection, keep reading.

A Leaf-Centric Bin

Back in my yard waste stalking days, I took a home composting workshop through my local municipal waste management center.

The method I learned there was brilliantly simple, and allowed me to create my own supply of black gold – relying heavily on my own autumn leaves, as well as those of many of my neighbors.

Up until this point, I had been trying (and miserably failing) to create compost in a plastic tumbler-style bin. The contents weren’t breaking down, and it was too small to be really useful for someone with big gardening ambitions such as myself.

Then I took the workshop and came home with a new system – and it worked like magic.

In this method, which also happens to be recommended by the Cornell University Cooperative Extension and by the Rodale Institute, among others, you start with a piece of welded wire fencing which you shape into a cylinder.

Add some twigs on the ground to help with air circulation, pour in a thick layer of leaves, make some room in the center to add a bucketful of kitchen scraps, then cover them up with dead leaves. Repeat until the bin is full.

Don’t worry – if you haven’t instantly memorized this process, step by step instructions follow here!

Essentially, each layer of dry foliage is like a bowl that holds the kitchen scraps or other “greens.”

There are layers of leaves on the sides and on the top at all times. It looks very clean, doesn’t smell, and doesn’t attract unwanted critters, since there is no rotting food spilling out of it.

Possibly the only disadvantage to this system is that it doesn’t work well in arid climates where the mixture of browns and greens will dry out too quickly. This is why I have transitioned to a more climate-compatible pit system here in Utah.

But for those of you in more temperate areas, there are many advantages to using this type of system.

Since the contents of the bin are in direct contact with the ground, it’s easy for decomposers such as fungi and other organisms to come in and do their work. And since the sides of the bin are made from wire mesh, it also provides great airflow.

Oh, sure, there are other types of bins that will work to break down leaves, too. The best ones allow your compost to be in direct contact with the ground, permit good airflow, and are light enough for you to move them around easily.

The model described here has all of those winning attributes, and it is extremely affordable.

Make Your Bin

Are you ready to make your own? Here’s what you’ll need:

  • An ample supply of leaves – if shredded, they will decompose faster, though this is not necessary.
  • A roll of 14-gauge galvanized welded wire fencing that is 3-4 feet tall. You’ll need a piece that is 10-13 feet long for one bin.
  • Wire cutters
  • Some twigs or dry stems
  • A small amount of finished compost as an inoculant (optional)

1. Using wire cutters, cut a piece of fencing that is 10-13 feet long. Make your cut so that you can bend the ends of the fencing to attach it to itself.

2. Stand the fencing up and form a cylinder, with about six inches of one end overlapping the other. Twist the cut ends to secure them to the other end of the fencing.

3. Locate your bin away from any trees or shrubs to conserve nutrients in the pile.

4. Place a layer of twigs or woody stems in the bottom of the cylinder.

5. Next, pour in a bag or two of leaves. You want about a 12-inch layer or so.

6. Form an indention in the middle and add your first batch of greens, such as kitchen scraps.

7. Optionally, you can add a small amount of finished compost to kickstart decomposition.

9. Water the contents of your bin thoroughly. If any food scraps are showing, add more leaves.

10. Every time you add greens to your bin, repeat the same process – make a “bowl” in the middle of the pile, add the greens there, cover with a layer of leaves, and then water it in.

You may have noticed that in this method, leaves are not only one of the compost ingredients, they are part of the structure of the system, creating a permeable liner within the cylinder of welded wire fencing.

This inner “liner” will eventually break down and turn into compost as well.

A note on fencing material: the 14-gauge galvanized welded wire fencing is rigid and will keep its shape even when empty, while other fencing materials such as chicken wire or plastic mesh garden fencing will slump, making your pile less easy to manage.

And since the welded wire fencing is galvanized, it is also very long lasting and can be used over and over again.

Managing Your Pile

Your pile should remain evenly moist, like a sponge that has been wrung out, so water it as needed.

You don’t necessarily have to turn your pile when using this layering method, though if you want finished compost faster, mixing it will really help.

Pamela Coleman, Agriculture Specialist at the National Center for Appropriate Technology recommends that during each mixing session, you give it at least five turns.

At some point – usually this is when your bin is full – you’ll need to stop adding new materials to it and start a new bin, allowing the first one to finish its work of decomposition.

As the contents of your bin decompose, the pile will settle, growing smaller. Don’t be tempted to keep adding to it at this point, just let it keep cooking away. But do keep watering it, and mixing it if you’re taking an active approach.

If you are keeping an unmixed “lazy” pile, your compost should be ready in around a year. A more actively managed pile should be ready to use in six months or less.

The timing will depend on your climate and when you started the bin – whether it was in gradually cooling weather or warming weather.

To check and see if your pile has fully decomposed, have a look at it when you mix it. When there are no recognizable materials left, and the compost is dark brown, crumbly, and smells like soil, it’s ready to use.

When decomposing primarily food scraps and leaves, there may be a few exceptional solids left in a compost that is otherwise ready to use, such as avocado peels, eggshells, and fruit pits.

These are slower to decompose, and can be screened out or picked out of the finished compost by hand, or broken down more before you add them to encourage quicker decomposition.

When your compost is ready, untie the wire ends of your bin, and pry the fencing away from the pile.

After you have harvested your black gold, you can start your pile over again in the same spot, or better yet, plant a tree or shrub in this well-amended location, and relocate your bin to a new spot.


Composting Leaves - A Worthwhile Challenge

Composting leaves is an excellent way to give your compost and your garden a boost. However nearly everyone runs into a problem when trying to compost leaves. Here is a quick preview of what's ahead here.

Tree Leaves are Great for Compost

Composting leaves, especially tree leaves is great for both your compost and your garden.

Most trees have long roots extending deep into the subsoil. They draw in the nutrients and trace minerals which have leached out of the upper soil layers.

Fifty to 80% of these nutrients end up in the leaves so you'll find tree leaves rich in trace minerals. They are nature's nutrient recyclers.

Most leaves provide a high carbon source or "browns" for your compost. In other words their C/N ratio is usually over 30, often around 50. Essentially this means they are low in Nitrogen. In a compost they'll need their nitrogen rich green counterparts.

Composting Leaves is Often Difficult

If you were to believe everything you read about composting I have to think you'd feel betrayed by the leaves in your compost. The word out there would have you believe that by mixing your leaves with a few greens, in a couple of weeks you'll be spreading a nicely rotted compost on your garden.

Not, I'm afraid. That huge pile of leaves you're coping with in the fall are tough cookies. They contain varying amounts of Nitrogen, Lignin and Calcium. A whole winter's time in the compost bin and there's a good chance your leaves will look exactly like they did when you added them.

Leaves have two problems in a compost:

  • Leaves have a tendency to mat, especially when not shredded. When matted they will create an impenetrable barrier to air and water.
  • Leaves take a long time to break down. They contain varying amounts of lignin which is extremely resistant to decomposing. Usually a year or two is needed to fully decompose leaves.

Not All Leaves are Alike

Leaves are collectively categorized with a C/N ratio of around 60. This places them firmly in the 'browns' or high carbon category of the compost pile. Their actual C/N ratios range from around 20 to over 100.

It isn't just the C/N ratio that tells how your leaves will perform in a compost. Decomposition is linked to the relative amounts of nitrogen, lignin and calcium they contain.

According to Ken Thompson, author of Compost (whose book I love for its straight forward info and humor), these are useful categories to use when composting leaves.

  • Good Leaves - those lower in lignin and higher is calcium and nitrogen - includes ash, cherry, elm, linden, maple, poplar and willow. Break down in about a year.
  • Bad Leaves - those higher in lignin and lower in nitrogen and calcium - includes beech, birch, hornbeam, oak, and sweet chestnut. I would also add magnolia and holly to this list. Need two or more years usually to breakdown.
For those who don't know the names of your trees or whose trees are not on the list here is a rule of thumb that may work for you.
  • Green Leaves - some trees shed green leaves. These can be added in moderate amounts.
  • Red or Yellow Leaves - These can be used in small amounts.
  • Brown Leaves - Should be avoided but are good for leaf mold.
A last Caution- avoid the leaves of black walnut and eucalyptus tree leaves. These plants have natural herbicides that prevent seed from germinating.

Tips for Successful Leaf Composting

Okay - so your leaves are sometimes slow to breakdown and have a tendency to mat. These are the two problems you want to try to resolve in your compost and here's how.

  • Shred your leaves. This will improve your success composting leaves because: Reduces the bulk of the leaves by about two thirds Reduces the tendency of the leaves to mat. Speeds up the decomposition process as more surface area is bared to the decomposers at work.
  • Mix shredded leaves with a high nitrogen source such as grass clippings. You can mix them by: Setting your mower to bag the clippings and mow the lawn and leaves together. You should get a well shredded and mixed material. Using a shredder pass both the nitrogen rich material of choice and the carbon rich leaves through together. A nice shredded mix results. Mix them by hand, a few forkfuls of leaves, a few of greens and stir.
  • If you are going to use layers make the layers thin so as not to get into big problems with matted leaves.

I've used two different leaf shredders and really like them. They are fast. You might consider getting one to share with neighbors. I take mine to the community garden in town to shred a bunch of leaves for our compost there.

I also like the idea of those reusable leaf bags both for carting pre shredded leaves to your shredder and storing the results. And of course an outdoor trash can to store beside your kitchen compost bin so you can balance the compost as you add your bits.

The Leaf Mold Option

Many experienced composters choose not to mix their fallen leaves into their composts. They instead handle them separately creating a special compost made from almost 100% leaves called leaf mold.

It's simple to make leaf mold. Just follow these steps

  • Shred your leaves with a shredded or your lawn mower. This speeds up the amount of time needed to make leaf mold.
  • Collect them together in either
    • A naked pile (they may blow around though)
    • A wire cage or a compost bin.
    • In big plastic bags.
  • Add water if dry and wait. a year or two until ready.
The process is slow - a couple or three years - but the product - leaf mold is a deluxe mulch well worth the wait.
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Some common problems with composting:

Symptoms Possible Causes Solutions
Unpleasant odor Lack of air because of compaction Aerate
Lack of air because of overwatering Add carbon and aerate. The carbon will absorb moisture.
Too much nitrogen (if it smells like ammonia) Add carbon and aerate.
Too wet Add straw or other carbon materials.
Pile doesn’t heat up Lacks moisture Poke holes in a pile so you can water.
Less turning Use fork to bring materials from the outside to the center of the pile
Hot pile cools off Less turning Use fork to bring materials from the outside to the center of the pile
Pile is damp and warm only in the center Too small pile Gather more materials and make a larger pile.
Lacks nitrogen Add nitrogen such as grass or manure.
Animals and pests get into the pile Meat or dairy added in the pile Avoid using meats and dairy products.
Some material isn’t breaking down Lacks nitrogen and moisture Add water if it’s dry and cover the pile. Add grass clippings or manure.
Less mixing Turn pile
Pieces too large Chop material that is cars before adding it to the pile.

Watch the video: Rhubarb Leaves


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