Asked April 30, 2020, 4:33 PM EDT

We have a compost tumbler that we have been adding food scrapes and dead leaves to since October. Not sure what to do now. Since we have been continuing composting, when and how to we start putting the compost on our gardens? There is food in there we added just last week. Not sure if it has ever got "hot" and "settled," and not sure how to tell if it is hot or settled. Would adding cut grass and more leaves help it heat up now? Since we are doing continuous composting, do we keep adding food and leaves while harvesting the compost in the tumbler? I did not cut up the leaves when I put them in so that may be impacting what has been going on.

Jackson County Oregon

12 Responses


I have 25+ years of experience with tumbling composters. Long ago my tumbler got infested with red-wiggler eggs, and so earthworms are doing some of the work in the tumbler.Their principle advantages are:
  • Ease of turning;
  • Ability to add food scraps readily - which I appreciate so much;
  • Depending on configuration, they are relatively rodent-proof.
Their disadvantages are:
  • Insufficient volume of materials to support heating;
  • If the tumbler is elevated, air circulates all around the compost, cooling it;
  • The compost is not accessible to various soil insects and worms, that do considerable work breaking waste down. They also contribute their poop, which, let's face it, enriches the plant nutrient value of the compost. :)
Here's how I use my tumbler:
  • When empty, I fill it 2/3 full of leaves or straw
  • I add food until it's pretty garbage-y
  • I empty the food waste and leaves and transfer to a standard on-the-ground plastic composter;
  • I take it though a number of turnings until it has heated several times, the food waste is no longer identifiable, and it is a bit more stable.
Granted, you likely do not want to be like me! My idea of a good time is 2-3 hours turning or sifting compost. I have 7 composters (including the tumbler) in my suburban backyard right now, and have had about that much compost working all winter.

To address your specific questions:
  1. If you cannot or do not wish to adopt my 2-stage method (either is perfectly rational), yes, you must stop adding new material until this compost is stabilized.
  2. Grass clippings are quite juicy at this time of year (~85% water). The soluble nitrogen addition will support heating. Mix them in well.
  3. I do not ever shred leaves. They take a long time to break down, depending on type, and likely will be spread on the garden still identifiable. But the insects living in the garden soil will be thrilled! and will pull them under the ground, where they will undergo shredding by insect mouth parts, and add to soil organic matter.
  4. You can tell whether compost is heating up by laying your hand on the top of the pile, or by using a thermometer. A jelly thermometer is far cheaper than a compost thermometer. You can still buy the old-time thermometer in a tube with a clip around the tube for under $5. I tie a piece of bailing twine around the clip so I can retrieve the thermometer from the compost. But that is not necessary - it's only if you want to amaze yourself. :) The hand test is good enough.
  5. Compost is stable when bacteria and fungi have broken the easily broken carbon-carbon bonds and the compost itself releases far less carbon dioxide and methane than it had when it was actively composting. What that means for you: compost that has sufficient moisture and fails to heat up appreciatively after turning is stable.
  6. You may well have very wet food waste and leaves in the tumbler. If that is the case, add shredded paper to absorb the moisture. This will shift the bacterial community in the tumbler to oxygen-breathers, who work more efficiently. Shredded paper is not only absorbent, but readily breaks down - faster than leaves.
I would be very happy to further explain or answer more questions to find a solution that works for you. Just write back! I believe that everyone who wants to compost will find a way that works for them.

Thank you so much Linda. You have brought clarity to our new entry into the world of composting.

My wife and I are reviewing your advice and will decide how to move forward soon. We may have more questions for you as we do.

I have been so frustrated trying to do Google searches and getting so much conflicting opinions. Thank you, thank you, thank you!!

Bill Ritch

Bill: You are welcome, welcome, welcome.

My master's project was about the chemical changes of compost over a 6 month period, but I had been composting ~25 years before I got that MS - late bloomer, me. :)

My undergrad degree from loooonggg ago was in human behavior. I bring the two together to help individuals who really want to compost identify the techniques that will work for them - long term.

EVERYbody on the internet is an expert, including me! :) Some of us legitimately so. There are others, well-respected, who disagree with me on some of my points, but that's OK. But I'm definitely not trying to sell anybody anything (speaking of Google), and I've been at it long enough to make most of the worst mistakes, and then have to find solutions.

Don't be afraid to try something out. See whether it fits your physical abilities and lifestyle. And if you like the compost. If not, you can always try something else. :)

Good morning Linda. We are working on a number of follow-up questions that I will be sending later today. Hope you are well and safe.

Janis and I have decided to adopt your two stage composting system. We have a number of questions about the general concepts of composting and the two stage system as well as detail questions on how to transition from where we are at the moment to your system.

I would like first give you an overview of the size of our gardens and how we have been fertilizing them. When we bought our house two years ago it came with beautiful organic gardens. We have had little gardening experience and been doing our best to maintain what was passed on to us.

· Garden

· 825 Sq. Ft grass lawn (Back Yard)

· 800 Sq. Ft garden beds (Front Yard)

· 136 Sq. Ft raised beds

· 120 Ft bushes along fence lines

· 50 Ft hedges around front yard

· Fertilizing (We have not done any fertilizing this Spring)

· Gardner & Bloome Organics Harvest Supreme ( Mulch on all beds in Fall)

· Home-brew organic fertilizer (Holiday Schedule-we missed Easter):

· 4 Parts Fishmeal

· 1 Part Dolomite

· 1 Part Rock Phosphate

· ½ Part Kelpmeal

· Lawn

· Gardner & Bloome Organics Lawn Fertilizer

· Ferti-Lome Natural Guard Soil Activator

We are not clear what the big picture is of the dance of a tumbler, composting bins, compost materials, compost, and garden soil: timing, movements, rhythms, etc. :-). So here are our questions. As you can see, we have lots, and some may overlap. We are very new to this. If this is over the top, perhaps you can direct us to some appropriate resources to study.

How do we integrate the compost that we will be making into our current fertilization? We understand that compost enhances the soil to create a beneficial environment for plants, fertilizer feeds plants.

· When during the year is compost added to our gardens and lawn?

· Have we missed the Spring window?

· Is compost mixed into the soil or placed on top?

· Should our grass lawn have compost?

· Should we continue using the fertilization materials we been using or modify them in the future with the addition of compost?

We understand that composting is the biological decomposition of organic waste such as food or plant material by bacteria, fungi, worms and other organisms under controlled aerobic (occurring in the presence of oxygen) conditions. The end result of composting is an accumulation of partially decayed organic matter called humus.

· How long does it take to create humus/compost using the Two Stage system?

· How long do you leave a batch in the tumbler before moving it to the composting bin?

· How do you decide when to move a batch from the tumbler to the bin?

· “When it is “pretty garbage-y.” Not sure if that means around a week of scraps from two people or a month?

· You said you “take it though a number of turnings.” Daily turnings for a week or a month?

· Do you keep adding materials from the tumbler to the bin or must the bin be emptied before putting more in from the tumbler?

· How long does the compost stay in the bin before going into the gardens?

· How do you decide when to move a batch from the bin to the gardens?

· Do you create compost all year long or is there a year-long rotation pattern?

· You mentioned having 7 tumbler loads of compost working all winter. So make compost in the winter and then stop during the summer?

· If a batch is “stable” but it is not time to put it in the gardens what do you do with it? Do we need a storage/holding bin in addition to a production team of a tumbler and a bin?

· We understand that creating heat is important to the decomposition process but we are not clear what that actually means?

· Is the goal to create heat for a specific period of time and then the decomposition is done?

· Or are there periods of alternating levels of heat and the decomposition process is also being conducted by bacteria, fungi, worms, etc.?

· “Stable” Status. You wrote “has sufficient moisture and fails to heat up after turning.” We are not certain what this means in practical terms.

· This seems to mean it has already heated up in the past and has been in the composter tumbler/bin already for a period of time? If so, how long?

· What we have at the moment is moist without heat after tumbling. Stable?

Here is current composting status.

· We have a Suncast Tumbler (Speed) Composter TCB6800 that holds 6.5 cubic feet.

· We have no idea what a speed composter means vs a regular composter.

· We bought the tumbler in January 2020.

· We have been adding food scraps and dead leaves to the tumble from January until three weeks ago.

· We added the materials at approximate ratio 25% green to 75% brown.

· We cut up the food into small pieces but did not cut up the leaves.

· It always seemed to be moist, perhaps because the leaves we added were damp.

· We did not tumble the tumbler consistently in January and then was told to not tumble it during the cold weather. We started tumbling more regularly mid-March.

· The bin is currently 50 % full and not showing signs of heat, maybe a little warm on certain days. We doubt it is ever been close to 140 degrees F.

· There is still food visible that has not decomposed.

· In attempt to reduce the moisture and increase the heat we added pieces of brown shopping bag paper.

· Not sure we shredded it enough.

· Not sure how much to added given the size of the batch we have.

Immediate questions:

· We have stopped putting food scraps in our tumbler two weeks ago. We have been putting leftover food in a metal container. Since the food is deteriorating without any balancing carbon (leaves), will we be able to eventually introduce this food into the composting when we are set up and ready to go? Should we mix some leaves in with it now? Or does it have to be put in the trash?

· I just cut the grass. If I am following your answers to our earlier questions correctly, should put grass into the tumbler now?

· What type and size composting bin should we buy? Cannot find anyone yet locally who has them in stock so may have to buy on line. Checking with Lowe’s.

· In November, before learning about using a tumbler, we were putting food directly into the soil in one of our planters. That soil is now very rich. Is this another form of composting? We have also been told we can let leaves and grass decompose and then use it has compost. Is that correct?

· The former owners left a small bin of red worms that somehow are still alive in a very small plastic container. Introduce them into the compost?

Wow! Please give me the week the respond to all of your questions. :) ljb

The very first thing I want to say to you is that you have inherited by purchase somebody else’s Garden of Eden. You should make it your own, rather than try to hold yourselves to someone else’s standards of gardening. You admit to limited gardening experience, but the questions you ask indicate to me that you are treading water in the deep end of the pool. It’s not given to everybody to own nice property! Enjoy yourselves and enjoy the property! Don’t turn it into some external standard against which you compare yourselves.

I’ve tried to answer all of your questions and have demarked the various sections in bold.

My personal goal is domestic waste management rather than optimizing soil fertility, tho’ I think we are doing well enough in that regard. Your questions about timing can all be answered in this way: We are two adults who cook mostly fresh and get 5-9 servings of fruits/veg per day. Frozen and canned produce left most of their waste at the cannery. It’s the accumulation of food waste on the kitchen counter that drives the whole composting process.

I’m also a real believer that this is only going to work over the long-term, (I’ve been going like this for ~45 years…) if it fits into the rest of your lifestyle and you really like doing it.

Managing the tumbler: Rather than answer the specific timing questions, let’s go from the kitchen to the landscape. Then if questions remain, ask.

  • I have two, 5-liter containers with tight-fitting lids on the kitchen counter. These are filled with food scraps during the cooking and clean-up process.
  • When filled, they are dumped into the tumbler, which begins with 2/3 of its volume filled with leaves, shredded paper, etc. They fill in our house probably 2-3 times per week. We turn the tumbler after fresh food additions.
  • Because the tumbler started out mostly filled with brown stuff, it gets pretty garbagy about every 2 months. I’ve never head anything about not turning the tumbler during the winter.
  • I empty the tumbler a wheelbarrow at a time into an Earth Machine or Soil Saver composter. Those are brand names I mention only so you can see the type of composter I refer to – those are not recommendations.
  • I layer the tumbler contents with dried leaves, or straw, or shredded paper – about equal thicknesses of layers, adding in any yard or garden debris, grass trimmings, or additional food waste from the kitchen as I go.
  • Especially in the winter and spring, I’m likely to add a pint of alfalfa pellets to the wet layers for an extra shot of nitrogen.
  • Then I will turn this composter maybe once every two weeks until I can no longer recognize food waste.
  • When the tumbler is empty – and I empty it all on the same day - I refill it with leaves and start the cycle anew.
  • When the food waste is no longer identifiable, I apply the compost if it’s needed. If it’s not needed, I have two trash cans.

Fertilizer Regime

  • Gardner & Bloome Organics Harvest Supreme and home brew: It can’t be cheap! It includes bat guano, chicken manure, worm castings – all nitrogen sources. I wouldn’t appy that in the fall – you’re losing all that nitrogen during winter rains.
  • If you’re fertilizing by the calendar rather than by plant need or soil test, you waste fertilizer and can threaten water quality.
  • I’m dubious about the beneficial mycorrhizae – those are usually specific to the plant, rather than just beneficial. It’s likely that the mycorrhizae associated with the roots of many plants have not be specifically identified.
  • In addition, you’re adding phosphorus, potassium, nitrogen and micronutrients in your home brew fertilizer, the components of which also are not cheap.
  • I generally don’t recommend that you add any liming agent, including dolomite or oyster shell lime without a soil test. Both will increase soil pH – not a bad thing, unless “calendar” applications take soil pH out of the healthy range for plants. Also, the magnesium content in dolomitic lime can build up in soils over time and compete with calcium uptake (also a component of dolomitic lime) by plant roots. You really should consider a soil test with agronomic recommendations. Likely you will want to dial back your fertilization program.

As for when to spread compost, my standard is when it’s ready – no identifiable food waste. And I pull out the inevitable large sticks and stalks and put them back in for more composting. Compost breaks down slowly in the soil and releases minute and decreasing amounts of plant nutrients over about five years. There is no “window” for amending landscape and garden soils.

Over time, I’ve shifted from mixing compost into the soil to layering it on top. If you apply compost to your lawn, that would be a very thin layer (1/2”) that you rake in afterwards. Lawn applications require sifting compost through a 1/2” wire mesh. I’ve done it more this year during the COVID furloughs than I have in my life ever. If you are willing to sift it, you can add compost to your lawn.

The beneficial environment for plants that compost promotes includes the release of essential plant nutrients through microbial mineralization. Organic matter can be considered part of the soil humus pool 6 months after it’s been added to soil. I do make compost all year long because we continue to eat all year long, but the process slows considerably in the colder months. Those were not 7 tumbler loads of compost during the winter, but 7 different composters including the tumbler. Because it was cold and wet, maybe I only emptied the tumbler once between New Years and April 1. I will continue to compost all season long, because we’re eating and generating a lot of garden waste and grass clippings right now. Because I have so many composters like the earth machine, if I don’t like the looks of compost (identifiable food waste) or don’t need it at the moment, I store it there or in designated trash cans.

Compost heats because the microbes doing the composting work release heat as a by-product of their metabolisms, just as we do (body heat). If compost is moist but not heating, it can be assumed to be stable, with the caveat that I have never gotten compost in a tumbler to heat. The 6.5 ft3 capacity is insufficient to be self-insulating. Apart from the tumbler, my composters are about 0.5-0.6 yd3, or about 13 – 24 ft3. Once the readily breakable carbon to carbon bonds are broken, the food supply is reduced, and the microbes slow down – that’s when it’s stable. Stable is not something measured by the calendar, its something you get a feel for by experience. If you want the serious science answer, please see the resources at the end; I’ve included the link to my master’s thesis on maturity and stability of composted yard debris.

Worms: you might choose to dump the worms into your tumbler, where they will begin to munch on food waste right away. Alternatively, you can see the references I’m providing, and manage them as a separate food waste management technique. I do both, but the worms are mostly for public demonstrations. We make too much food waste to manage it in the garage, which is where I keep the worms. I don’t have that much space. If your read Worms Eat My Garbage, you’ll understand space requirements for worm bins. It’s a quick and easy read. You can’t put those worms into a hot compost – they’ll just leave through the bottom of the composter. They can’t live in mineral soil – not enough organic matter to feed them. So, compost or worm bin are the best bet if you’re interested in keeping the worms going. But make that a conscious choice.

Immediate questions.

  1. I would continue to add the food scraps into the tumbler until you are ready to move the tumbler contents into another composter.
  2. Yes, fresh grass is better than aged. Add more leaves or shredded paper. Grass at this time of year is about 85% water. I think it’s a waste to stack up grass clippings – they do so much to enrich compost by adding water (one molecule at a time) and nitrogen. Their juice contains soluble sugars, which rev up microbial metabolism.
  3. Many leaves will just sit in a wet stack without appreciable decomposition for 5+ years. By adding a little nitrogen, and turning they break down much faster.
  4. Any black thing that sits on the ground, has no bottom, and is made of black (recycled) plastic is a good enough composter. Recycled plastics are often dyed black because the mix of colors would otherwise be a muddy gray. Go for price – less is better.
  5. Humans have been burying organic waste since they stood up on two feet. There are records in ancient Greek literature about burying waste. Modern-day great apes have been observed to bury fruit and return and eat the fermented results.

Resources Here are some extension publications that may guide your composting and soil management plans into the future. All are free and online.

A Guide to Collecting Soil Samples for Farms and Gardens

Analytical Laboratories Serving Oregon

Worms Eat My Garbage by Mary Appelhof. Available online and in bookstores.

Improving Garden Soils with Organic Matter

Maturity and stability evaluation of composted yard debris by Linda J. Brewer. MS Thesis.

OSU Organic Fertilizer & Cover Crop Calculator: Predicting Plant-available Nitrogen

Soil Organic Matter as a Soil Health Indicator: Sampling, Testing and Interpretation

Baseline Soil Nitrogen Mineralization: Measurement and Interpretation

Thank you Linda so much. "Above and beyond" considering all of our questions!

I just found your answers today. For some reason I did not get a message from alerting me that you had responded on the 18th.

My wife Janis started our compositing as domestic waste management as well.

Lots to think about. I will study your answers and advice this week end, look for a bin, and see if we have any follow-up questions. I am assuming, if we do, they will only be a few. :-)

Can we start putting what is now in our tumbler into the gardens, or should we put some or all of it into a compositing bin first. The food in the tumbler is no longer recognizable except for the egg shells. I am guessing they should not be in there? If not, should we pick them out?

Personally I have no objection to egg shells in the garden. Ultimately, and over a long period of time, they will break down and contribute calcium to the soil. You get to choose whether to pick them out or not.

As for spreading all of that content onto the gardens or putting it into another composting bin first, go by smell. If the smell is more soil-like, it should be fine to spread. But connect with your raccoon brain before spreading - is it something that would appeal to an animal? :)

On June 9 at 12 noon, I'll be the guest speaker about compost - specifically responding to participant questions.
If you can, be sure to attend!

Thank you Linda. We are planning to see you and hear you on June 9.

Bill and Janis

Hi Linda, Well we finally emptied our tumbler!! The compost has so far gone into our vegetable garden and new rose plants.

We have decided to get an Earth Machine to implement your two phase system. Unfortunately, finding an Earth Machine is proving challenging. We are on a waiting list for one from Home Depot when they are back in supply. No one else is the area seems to sell them. But we do not need one for about two months, so we are hoping all is well.

Bill and Janis

Remember: Any black thing that sits on the ground, has no bottom, and is made of black (recycled) plastic is a good enough composter. Earth Machine is one brand among many good brands. But if Home Depot is convenient for your, and two months is fine, it sounds like a good choice. Hope you can zoom in tomorrow. :)