117-Compost, Compost Tea and the Soil Food Web, with Dr. Elaine Ingham

| Compost, Podcast

Last week, we “dug” in to the subject of the soil food web with guest Dr. Elaine Ingham. I have long followed and admired Elaine’s work in soil science study, and hearing her describe that it’s actually our plants which are in control of the complex cycle of life beneath the soil surface was fascinating.

If you missed Part One of this two-part conversation, I strongly recommend you begin there. Understanding the relationships between plants and the legion of microbial life within our soil is key to making sense of this second half of the discussion.

Today, we focus on improving the biology in soil through composting, along with how to brew and use compost tea. As we learned last week, making or purchasing compost locally will pack a greater beneficial punch in your garden than applying a product produced hundreds of miles away.

So, how can you take that knowledge to the next level and fine tune your soil food web? Not all compost is created equally. Inputs, timing and temperature can make all the difference.


Dr. Elaine Ingham

Elaine and her team at Soil Food Web Inc. are training a new generation of soil consultants to help meet the need of large agricultural organizations making the shift toward organic soil management. (photo: Courtesy of Soil Food Web Inc.)


Composting Life Back in to Dirt

In Part One of this series, Elaine explained the difference between dirt and soil. Soil is full of life. Dirt, on the other hand, is sterile – lifeless, and that is due to a lack of oxygen and adequate organic matter.

Even when it’s only marginally healthy, soil contains organisms collectively known as the soil food web. It might sound strange, but those organisms – fungi, bacteria, protozoa, micro-arthropods, earthworms, etc. – are just like us in some ways. They require water, oxygen and food for survival. Also like us, they eat, reproduce and die. Blunt, I know, but true.

Healthy soil is teeming with billions of these life forms, each of which play a fundamental role in plant health – and even in our digestive health. As the organisms of the soil food web work, they extract nutrients bound up in soil aggregates. In the process, they build microscopic pathways which aerate soil and improve its ability to retain proper moisture levels.

Those are all very good things, so clearly, we want as many of these microorganisms at work in our soil as possible.

When soil is unhealthy – or lifeless dirt – how do we transform it into a robust soil food web workforce? Well, compost is the best place to start.

Quality compost will feed any active microorganisms already residing in your soil, which will encourage them to multiply. Compost also contains a new population of microbes which make their way into the heap from many sources, including the surfaces of the input materials (food scraps, garden debris, etc.).

Consequently, the species of microorganisms present in the compost will depend on the inputs. The balance of life will also be determined by the compost heap conditions. A booming population of beneficial microbes relies on a good balance of water, food (inputs) and air.


beneficial nematode of the soil food web

Here is a 100x magnified image of a beneficial nematode, which will feed on the fungi and bacteria and excrete the valuable nutrients they hold in a plant-accessible form. (photo: Dr. Elaine Ingham)



Microorganisms must have water in order to perform their decomposition business. This is why the moisture level will impact how quickly a compost heap breaks down. If you opt to take a “hands off” approach and leave things to an occasional rain and the moisture contained within inputs, A small microbial population will eke out an existence, but they will take longer to make their way through the raw materials you add to the heap.


The microbes which gather in a compost heap require some greens (nitrogen) and some browns (carbon) as a food source. Think of it this way: If all you had to eat was potato chips week after week, it would be enough to sustain you, but you wouldn’t be very healthy or very active. If you receive well-balanced meals every day, your energy surges, and you are more productive.

The same is true of microorganisms. When they have a good balance of food, they can work harder and faster to break compost inputs down, while also taking quick breaks to, um, reproduce. These creatures recognize when they have an environment primed to sustain more life, and they respond by multiplying.


Just as in soil, life in compost is critically impacted by oxygen. In Part One of this series, Elaine discussed the effects compaction has on life and nutrients in soil. Compaction squeezes out oxygen particles, creating an anaerobic environment which kills life and causes mineral nutrients to convert to toxic substances, including alcohol.

The same responses occur in a compost heap if it becomes compacted. The varying sizes of the materials you add to the heap create tiny air pockets which allow oxygen to move through the pile. As those materials break down, the natural air pockets are lost, so turning the pile periodically with a pitchfork, for example, is an important step to re-infuse the entire pile with a fresh supply of oxygen.

Just like a good balance of food and water, air keeps microorganisms healthy and actively working to break down materials into finished compost.


Composting operation

Some of Elaine’s clients are composting on a massive scale and require large equipment to aerate the materials and keep the heap aerobic. (photo: Courtesy of Soil Food Web Inc.)


Let It Breathe

How can you tell if your compost heap has become anaerobic? Use your nose.

If your compost heap smells bad – sour, rotten eggs, etc. – it’s telling you it needs oxygen. A healthy decomposing compost heap should always smell earthy and clean. Since the exterior surface of the pile is exposed to the oxygen it needs, you might not notice a problem unless you check for it. Take a moment to dig in, and if the interior has a foul odor, that’s a red flag the pile is suffocating.

Before you see or smell any of these warning signs, the biology within a heap starts to shift. Anaerobic organisms – bacteria – begin to grow. The anaerobic bacteria begin to consume the fungi that you want to promote.

If you come across a white, ashy layer somewhere on the interior of the pile, that’s an indication of a build-up of anaerobic bacteria. It’s your only visible indicator that the compost heap is in danger of going anaerobic

I turn the materials in my compost pile once a week, and in all the years I’ve been composting, I’ve never had a pile turn (or in danger of turning) anaerobic.

Now, I get it – sometimes life gets in the way of even the most well-intentioned composter. So if you see or smell a warning sign that your compost heap is going anaerobic, a thorough mix-up or turn of the material will infuse it with oxygen and get you back in the right direction.

An alternative to turning the materials is to use the handle of a shovel or some other long, round pole to punch holes in various spots through the heap down to the bottom. The holes become chimneys which allow heat within the pile to rise, so cool air can be pulled down into the cavity – aerating the surrounding materials.

Creating good compost, rich in nutrients and beneficial microbes, isn’t hard. It just requires a little bit of attention.


Measuring compost temperature

A compost thermometer is a valuable and inexpensive tool for monitoring the core temperature of a compost heap. Regular temperature readings can really help you understand whether or not you have achieved a good balance of browns, greens, air, and moisture. ( (photo: Courtesy of Soil Food Web Inc.)


The Hot Spot

Have you ever seen steam rising from an active compost pile? That heat isn’t generated by the sun or any other external source. It’s generated by the activity of the microorganisms. They are so furiously consuming and multiplying that they actually put off heat, and once the party really gets going, you can see the heat rise in the cool of the morning. That never ceases to fascinate me.

If you don’t already own one, a compost thermometer is an inexpensive tool to help you gauge the health of your compost. The thermometer has a long probe which, when pushed down into the center of the heap, determines the temperature at the core. Anytime you see reference to compost temperature, it’s the core temperature that matters.

Strive for a temperature of at least 131 degrees Fahrenheit. Pathogens, weed seeds, pest eggs, parasites and other undesirables are unable to survive at that sustained temperature or above.

Microorganisms are more active and reproduce much more quickly at higher temperatures, which is a good thing. During this high level of activity, they consume more oxygen, more water – and more food, which turns raw materials into finished compost more quickly.

While we all want to get our hands on finished compost sooner rather than later, it is possible for a compost heap to become too hot. As temperatures reach around the 170 degrees Fahrenheit mark, so much oxygen is being consumed by the frenetic activity of microorganisms, that the heap is in danger of going anaerobic. So, it’s a good idea to take a few minutes and check the temperature of your compost heap every day during its most active early phase.

Once it’s finished and ready for the garden, compost will be a soil-like consistency and an ambient temperature.

You can choose to work compost into the surface of your garden and landscape, but that’s really an unnecessary step. Microbes already in your soil will join forces with the new team of microbes in the compost to incorporate the amendment into the soil through those microscopic pathways I keep mentioning. You might have been taught to turn it all in, but overworking compost into garden beds breaks up any pathways which already exist.

After you amend, cover the bed with a 2-4” layer of natural mulch. That will protect the surface and the compost from erosion, and it provides another organic food source to promote a healthier soil food web.


Dr. Elaine Ingham with clients

Elaine has been consulting with clients all over the world to convert compacted, anaerobic fields into rich soil. (photo: Courtesy of Soil Food Web Inc.)


Compost Tea

Another method for putting compost to work in the garden is to use finished compost to brew compost tea – a liquid used as a foliar feed.

In Part One, we discussed the microorganisms which live on the above-ground surfaces of plants. One of the many jobs of these creatures is to protect the plant against attack from disease. As a spray, compost tea delivers that beneficial soil biology over the entire surface of the plant.

Microorganisms adhere themselves to each other and to the compost material. So, the first step in creating compost tea is to extract those creatures using water. These tiny organisms are mightier than you might think, so removing them takes more than a good soak or running water. It takes a forceful and precise amount of water pressure to disengage them from the compost materials.

Elaine describes the process of extraction and recommends a cone tank and an air pump to get the job done. The pump is attached at the base of the tank, which is filled with water. Once the pump turns on, it moves the water within the tank. The higher the level of air being pumped into the water, the greater the pressure from the water movement.

The air is pumped into the tank just enough to create the appearance of a soft, rolling boil in the water. According to Elaine, that’s an indication that the pressure of water moving around in the tank has reached around 80 psi – the point at which the organisms are pulled from the compost material.

A small bag of compost is placed into the tank right in line with where the air bubbles are moving up from the valve of the pump.

This process doesn’t take long. In fact if the correct pressure is maintained, about 75% of the organisms living in the compost are extracted within 15 minutes. Compost containing a good population of fungi will turn the water a deep brown color. However, water which turns yellow or a honey-like shade contains mostly bacteria.


Dr. Elaine Ingham making compost extract

Here, Elaine is filling a mesh bag with compost to prepare it for the extract process. The cone tank behind her on the left is connected to an air compressor to move water at sufficient pressure to force the microorganisms bound in the compost to release into the water. (photo: Courtesy of Soil Food Web Inc.)


As we learned in Part One, a higher ratio of bacteria in soil is ideal for promoting weeds. We want a higher fungal count for our garden to benefit our desired ornamental and edible plants most.

Once the organisms have been extracted, they should be allowed to multiply in the extract. Feeding encourages reproduction. So, where does the food source come from? Food products are available for purchase which, when added to the water at the start of the extract-making process, will feed and promote multiplication of specific types of organisms after extraction.

Is your goal to increase fungi or protozoa? There’s a food designed for many of the microbes within the soil food web, which means the biology in compost tea can be customized.

When kept at a temperature of 70 degrees Fahrenheit or warmer, the organisms will be active and ready for garden application within 24 hours. Microorganisms are less active in cooler temperatures, so extract stored at cooler temperatures, requires up to 48 hours for the population to expand to the point that the tea is ready to apply in the garden.

One organism population which cannot be grown is the nematode. These creatures will be present in compost and compost tea, however beneficial nematodes reproduce more slowly than their microscopic neighbors. Their population will increase over time in your garden, but they won’t multiply in compost tea.


Soil fungus under a microscope

The world under a microscope is pretty fascinating for kids of any age. Check out the structured segments of this soil fungus at 400x magnification. (photo: Dr. Elaine Ingham)


Where the Magic Happens

Finished tea sprayed on plants, delivers the soil food web cycle right to foliage. Just like under the soil surface, the fungi and bacteria in tea are loaded with nutrients from their time spent feeding on organic materials. As the protozoa and other microbial predators feed on the bacteria and fungi, the excess nutrients are excreted in a form that plants can take up through stomates.

Stomates on leaf surfaces open and close based on the concentration of CO2 in the surrounding atmosphere. Like humans, the microorganisms of the soil food web consume oxygen and expel CO2. So when you spray them onto foliage in compost tea, they increase the level of CO2 near the foliar stomates and the stomates open to take in the nutrients the microorganisms make available.

I don’t know about you, but I think that is pretty amazing. All of this magic is happening in our gardens every day. We just need to be more aware of it and learn how to give way to these remarkable cycles of nature.


Compost tea application

Compost tea can be applied by a humble pump sprayer in the home garden or using heavy equipment sprayers as seen here on a seed potato crop in Montana. It is also disbursed by air, using planes and helicopters. (photo: Courtesy of Soil Food Web Inc.)


Keeping It Local

Okay – maybe you aren’t able to make your own compost due to space restrictions or HOA covenants. Maybe you make the compost, but you just don’t have the time (or the inclination) to make compost tea. Purchased products are widely available, but as I always say, quality is key.

If you purchase compost, look for certified compost, so you can feel good about the quality. Also, look for local compost, since it will contain more of the microorganisms needed by plants in the mineral makeup of your area’s soil.

Many nurseries and garden centers also offer compost tea for sale, but as with all things, buyer beware. Some companies brew tea for several days before they contain it to grow the microorganisms. During that extended brewing period, the microbes become inactive. Within a few days of brewing, microorganisms stop multiplying and actually fall asleep, which means they won’t be alert to glue themselves to the surface of your plants when sprayed.

That matters, because if they don’t adhere themselves to your plant, most of the population rolls off to the ground.

How do you know if the compost tea at your local nursery is worth buying? You could check the color. Again, it should be a dark brown to indicate that it contains plenty of fungi, but that’s no guarantee it’s worthwhile. The best way to judge the quality of compost tea is to bring a little home and look at it under a microscope.

You do own a microscope, right? No? Well, this might just inspire you to add one to your must-have list.

Through the power of magnification, you can determine if you have a higher level of bacteria or fungi, whether or not you’ve got some predatory microbes at work, and how active all those creatures are.

A microscope could not only show you the quality of compost tea you are considering but, also, reveal the biology in your soil and compost. Gathering this information may take a little time and effort, but if you have kids or grandkids, this activity will be a hit. Together, you can actually watch as the predator organisms eat the bacteria and fungi, which is pretty cool for kids of all ages.

Plus, knowing which aspects of your soil food web need fine tuning will give you a leg up in arming your plants to feed themselves through this natural cycle and be better equipped to fend off pests and diseases.

Once your soil food web is robust, your garden problems and maintenance will go down, and your plants will be healthier than ever.


organisms of the soil food web

You can determine just how active your compost tea is by viewing it under a microscope. Under the magnification, you can observe their movement and even watch as larger organisms feed on the bacteria and fungi. (photo: Billy Schlee)


The Devil Is In the Details

The subject of compost tea has always been a little controversial. There are some soil scientists who feel it’s useless or even harmful. I asked Elaine for her take on why opinions vary so widely. It’s her observation that it comes down to using quality materials and the right technique and timing.

For example, compost tea will contain pathogens if it is made from compost which didn’t reach temperatures hot enough to kill them. Spray those pathogens onto your plants, and voila, you’ve got problems. Tea made from composted manure could cause serious harm if the manure contained harmful pathogens. Manure from animals given feed treated with antibiotics will carry those antibiotics forward into the tea, and that will kill soil biology.

How the compost and tea are made will effect the impact – good or bad – an application of compost tea will have on your plants.

Is it necessary to use compost tea for a healthy garden? Not necessarily. Elaine suggests that it is worthwhile in the first season or two of converting poor soil (or dirt) into a healthy growing medium. Compost tea will cover the foliage of your plants with good biology which can reduce or eliminate the need for you to treat for disease.

A foliar application of compost tea won’t be necessary, once your soil food web is established and humming along with yearly or twice-yearly amendments of compost and a layer of natural mulch. There will be enough microbial life that the beneficial insects in your landscape will spread it on to plants for you.

So, has this two-part dive into the mind-boggling world of the soil food web whet your appetite for more? Elaine’s online courses or consultation training program might be of interest to you. She and her team at Soil Food Web Inc. are working with more and more large-scale agricultural operations all over the world and are in need of a new team of soil science consultants to help these operations convert from toxic chemical-based agriculture into a biological agricultural approach.


GEOTEA compost tea brewer

GEOTEA machines are designed to make compost tea on a large scale. You can see the rolling “boil” on the water surface and the dark brown color indicating that the compost used for this tea has a good fungal population. (photo: Courtesy of Soil Food Web Inc.)


You may have some follow-up questions for Elaine. Well, I’ve got good news. I plan to invite her back for a Q&A session to answer the questions that audience members are sharing in response to this series. Submit your question in the Comments section below (or in Part One), and I’ll be sure to include it in my follow-up podcast.

Last but not least if you haven’t listened to the recording of this podcast, I hope you will scroll to the top of this page and click the Play icon in the green bar under the page title. Hearing my dialogue with Elaine will help to reinforce the wealth of information that came out of our conversation.

Links & Resources

Episode 016: Composting Guide A to Z: The Quick and Dirty on Everything Compost

Episode 116: Understanding the Soil Food Web, with Dr. Elaine Ingham

joegardener Online Academy: Master Pests, Diseases and Weeds – my newest online course! Just $47 for lifetime access.

joegardener Newsletter

joegardener Facebook

joegardener Facebook Group

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joegardener Twitter

Soil Food Web Inc.

Compost Thermometer

Soil Cubed – Our podcast episode sponsor and Brand Partner of

About Joe Lamp'l

Joe Lamp’l is the creator and “joe” behind joe gardener®. His lifetime passion and devotion to all things horticulture has led him to a long-time career as one of the country’s most recognized and trusted personalities in organic gardening and sustainability. That is most evident in his role as host and creator of Emmy Award-winning Growing a Greener World®, a national green-living lifestyle series on PBS currently broadcasting in its tenth season. When he’s not working in his large, raised bed vegetable garden, he’s likely planting or digging something up, or spending time with his family on their organic farm just north of Atlanta, GA.

0 Responses to “117-Compost, Compost Tea and the Soil Food Web, with Dr. Elaine Ingham”

  • Bren O'Reilly says:

    How can I tell if the free municipal compost that my town offers is actually healthy compost versus “putrefied organic matter”? My town picks up leaves but refuses grass clippings, encouraging homeowners to use mulching mowers that allow the clippings to fertilize the soil. The facility has several huge piles of leaves and debris that get moved around, and one finished pile where residents can pick up multiple canfuls every day. It doesn’t smell. https://uploads.disquscdn.c

  • Melinda says:

    Question for Dr. Ingham: Does she have any tips for composting in one of those plastic compost tumblers? I live on a tiny suburban lot and don’t want to risk ticking off my neighbors with a compost pile (nor do I have a great spot for one), so I’ve been using a black plastic tumbler (which, btw, was provided virtually for free by my municipality). Is spinning the thing periodically enough or do I still need to get in there with a shovel? It seems to take forever to produce anything besides rolly-pollies, but I’m admittedly not the most consistent. The bin also has a reservoir underneath that collects what they say is “compost tea”–basically just the run-off from the bin–but it sounds like that is unlikely to be useful stuff. Any thoughts, info, about these types of set ups? Thanks! Loved the show!

  • Forrest Jones says:

    Joe, this was just as intriguing as the first half. I will have to listen several more times just to begin to get a grasp. It makes perfect sense that it is complex and Dr. Ingham isn’t even drilling down to the molecular or particle level of physics, this is biology. I won’t let it freeze me in my tracks, but I am willing and ready to learn and try to improve my gardening practices.I follow the philosophy that “compost happens”. I have 3 pallet bins. I layer the ingredients in layers as they become available. I heap them all the way above the top of the bins, When they drop by a third I heap on top of that again. I never checked, but I don’t know if they get hot. I never add water, they are open to what ever rain and snow that falls. The three bins are in different stages. After 2 years they are reduced to about 1/3 of what I topped off at and then I use it. When I harvest a bin, usually the top 10% isn’t ready and gets moved to another unfinished bin. But the remainder looks good and smells good. So I am curious what Dr. Ingham would say about this technique and how she would check the end result. I feel like it would be what goes on in nature
    The results of using both granular and soluble fertilizers are usually pretty obvious and immediate. Plants and grass get a darker green and they put on growth. While I know that the salts in those products are not good and I quit using them except for, milorganite, I would like to hear her speak about those quick boosts to the plants diet. Why do they work if they are lacking the biology that is required?I was thinking about getting biochar. Is there biology left in the biochar and if it is non native biochar would it be the same as non native compost?I was pleased to here that it is possible to make a compost tea that works. I am going to look into what it will take to get all of the components to do it right. Oh, and I need a microscope. Thanks again Joe , Elaine and Erin. Keep these coming.RegardsForrest JonesNanty Glo, Pa

  • Lyn Lull says:

    I have a question on compost tea. I have heard a lot about Comfrey and using it to make a compost tea, adding it to compost piles and just laying the leaves down on the garden as a mulch. What do you and Dr. Ingham think about comfrey and its uses, especially about using it as a compost tea. Thank you

  • Darby says:

    I’m a longtime geeky admirer of Dr. Ingham. I have a homemade air lift compost tea brewer that I use in the summers. My compost tea recipe varies but is mostly based on her recommendations – soluble kelp, fish hydrolysate, humic acid, vermicompost/compost and rain water. Occasionally, I’ll add alfalfa meal, ground malted barley, insect frass or water from my freshwater chemical free aquarium.I wanted to know Dr. Ingham’s thoughts specifically on the use of chemical free freshwater aquarium water in a compost tea. On its own, my plants LOVE water from the aquarium, but I’m wondering if it’s overkill to have it as the base of my tea. And, I wasn’t sure if the biology in the water is out-competing the biology in the compost that is added to the tea or vice versa.

  • Jeremiah Natte says:

    This was a very interesting episode. I’ll admit, I was mostly interested in the compost tea discussion. I have been very critical of compost teas. I’ll admit this episode has changed my mind somewhat on the topic. Dr. Ingham points out that it’s really best used to add beneficial microorganisms early on and has diminishing returns after only a few years. This is a much more limited application than is often recommended, and much more logical and science based than what I usually see by advocates of compost teas.I’d be interested in hearing Dr. Ingham’s take on Korean Natural Farming, bokashi, rhizobia (including rhizobial innoculants), biochar, and whether the mycelium of edible mushrooms added to the garden are beneficial to plants. I understand that’s quite a lot, but even referencing those in passing would be interesting.

  • Jeremiah Natte says:

    I’d also be very interested in the question on aquarium water.In addition to Darby’s question, I wonder if used aquarium water would best be used as part of a team, applied to a compost pile, or given directly to plants

  • Jeremiah Natte says:

    Hi Melinda,
    I’m not Dr. Ingham, but the ‘compost tea’ your tumbler produces is technically leachate, not compost tea. Dr. Ingham’s opinion may vary, but I think you’d be best off just putting that back in the bin when it needs moisture.

  • Vicky says:

    I would be very leary of that compost!! It maybe a bit safer than most since no grass so no Weed and Feed in the mix but you don’t know what all is in there.

  • Abeer says:

    Hello Joe
    My name is Abeer I am from Saudi Arabia and I have been listening to your podcast for sometime and have learnt a lot from your podcast and YouTube channels. I used to grow in containers but two years ago I made three raised beds in the garden to grow food. I was so disappointed because I discovered that the soil has Root Knot Nematodes. I went back to gardening in containers again and tried to know how to overcome this problem but all solutions, like solarisation and so, have mixed reviews. So my question is for your next episode on the podcast to Dr. Elaine Ingham is if I make compost in my garden, with the soil having Root Knot Nematodes, would that make the compost carry those? And would I be infesting other areas, like my containers, if I use this compost?

  • Sharon Carson says:

    I buy no bagged soils because they use poultry manures from cafos as a nitrogen source . I make my own compost with my horses manures .I use sawdust for bedding because staw is full of chemicals. I buy hay from a local farmer who does not use and chems on the field. I never need to turn my compost and it is turned and composted by the worms and other critters in the pile .I do cover it with a tarp to keep off excessive rain and contain the moisture .The real test is how well the foods grow in the garden and the wonderful taste of the foods… biodynamic preparations are very helpful in transforming the pile .It is all done by hand… there are no machines here.

  • Forrest Jones says:

    Joe, after listening to 116 and 117 numerous times, I realize that I need a Soil Biology 101 course in order for these to really sink in. Hint, possibly thru the joegardener academy?? It has been a long time since I had a general biology course.One of my questions , Do any of us really just have dirt since the soil food web extends down so deep? It would seem to me that we would only find dirt in a deep mine or quarry. Maybe we are talking about poor soil with low amounts of organic matter in just about all cases and not dirt.It seems that making good compost and extracting brews, that is compost tea, is a pretty exact science to get it right. We are really just trying to speed up the natural process that our forests and prairies have done a pretty good job of all on their own. Would just applying a blend of mulches accomplish the same thing? It seems that nature has a way of dealing with the bad stuff for the most part. That is what you are doing when you use the leaves that you and I both love. They seem to feed all of our woodlands everything that they need. The podcasts are making me lean towards the “compost happens” practice rather than a lot of manipulation by me.The podcasts also are making me think that maybe cover crops is the way to go every fall. I could simply mow them with a string trimmer in the spring and make furrows or holes to plant in. My home state of Penna has done what I think is a pretty remarkable job of reclaiming abandoned strip mine lands and requiring new strip mine lands to be restored. That dirt/soil that came from deep in the ground easily grows whatever seed mix they are using. After a few short years it is filled in thick. That tells me that the grass is feeding itself with each winters die back. And it only takes a few more years before you see trees coming up on their own. While they may not be the most desirable trees at first, I think that they will all come back eventually. I think it is a good example of an extreme disturbance where nature is doing its job without further influence from us. So yes to cover crops.And finally I heard about how important oxygen and creating air space is for soil health. That makes me wonder if that was why the double dig guys had so much success in spite of that disturbance. Could it be that getting the oxygen in is a bigger factor to soil health than we give credit to?Thanks again Joe, Elaine and Erin

  • Emma Jansson says:

    Hi, Very interesting podcasts! You rarely find information for gardeners to this level of detail and focused on the science behind! Thanks you for providing that!
    As another respondent – am also interested in Dr Ingrams views on bokashi where anaerobic processes are part of the concept. One benefit I find is that the volume of the compost is preserved i.e. less carbon is released to the atmosphere – that must be a good thing right?
    I also wonder, if plants need a soil food web to grow healthy, how come hydroponics can provide crops using rock wool as substante and where the plants are being fed a nutrient solution (which I assume is rather sterile)
    Looking forward to learning even more!
    Best regards Emma

  • David Loszewski says:

    Am I the only one that’s more confused than I was before listening to these two podcasts? Don’t get me wrong, a wealth of information and I learned a TON, but it sounds like without a microscope and the skill to read the results there’s really no way to tell if you have healthy compost? If I have a pile of ready to go compost that’s been sitting in my yard for the last year, how I can I tell without using a microscope that it’s not full of bacteria? She was also strongly against using animal manure, but I’ve always been told that chicken, cow, rabbit, and goat manure are perfectly fine to use. Up until now I’ve been doing the touch and smell test that Joe has been teaching us and will probably continue to do.I never new about the white ash being a sign that your compost is burning too hot which I often get when I throw in a pile of grass so that was great to know!Thank you for the podcasts! Love them all!

  • Catherine Jacobs says:

    I am curious what would be considered over tilling? For instance, I have raised vegetable beds similar to yours and mulch with straw. At the end of the season I till in the straw with a compact tiller after the plants are removed. Is once a year too much tilling?

  • Joe Lamp'l says:

    The more I study the concept of no-till, the more I think any tilling is more than necessary. Lately I’ve been studying the work of well-known British gardener, Charles Dowding. He’s considered one of the elite gardeners and his whole approach to gardening success is using lots of compost as mulch and no-dig (which is far less destructive to the soil structure than tilling). He’s never tilled his garden and he has the most amazing crops. He even does side by side test plots of digging vs. no-digging. The no-dig crops always perform better.Years ago I went from tilling the first time I was preparing a garden bed to no tilling at all. And I have to agree, the results I’ve seen are amazing. So is tilling once a year too much as you’re incorporating straw. The soil science and scientist would likely say yes. The network of fungal hyphae and mycorrhizae extend very far when not disturbed. Tilling obviously breaks that up and burns up organic matter in the soil as new oxygen is rapidly introduced.Another downside to tilling, even once a year with a compact tiller is that the soil consistence difference from the tilled area and the area below tilling creates a layer that slows down drainage.So even though once a year doesn’t sound like much at all, the more I study and practice no-dig, no-till, the more I think it’s the right approach. The material you are tilling into the soil could be left in place on the surface, or moved to a compost bin to finish decomposing there and then added back as a topdressing. That’s what I would do.

  • Joe Lamp'l says:

    Hi David. I totally understand your confusion. This is why I want to have her back, to answer follow up questions like yours and mine. I would not get caught up in the details of what Dr. Ingham is suggesting, especially if you are getting good results. There is not only one way to successfully compost.
    So, thanks for leaving your comments and questions here. I will be adding them to my list for Elaine.

  • Joe Lamp'l says:

    Thank you, Emma. Your questions are noted and I’m glad you asked about these. I will include them in my follow up conversation.

  • Joe Lamp'l says:

    You are always thinking, Forrest and we love that about you!
    First, great idea on Soil Biology 101 for the joe gardener Academy! Adding it to the list now. Really.On dirt vs. poor soil, I suspect more often, it’s the latter that we have. But the percentage of organic matter found in most native soils is almost always under 5% and usually closer to 1%.Elaine Ingham is very much about the exact processes to fine tune your compost or brew, and most of us don’t take it to that level. I knew these were going to raise as many questions as they answered and you have demonstrated that here. As I’ve said a time or two, there is not only one right way to garden, make compost, or improve your soil. But for all the science nerds out there, this would scratch their itch a lot, while raising more questions for many of us.I’ll be getting back to her for another podcast to address these questions, including yours. Thanks Forrest!

  • Joe Lamp'l says:

    You can’t argue with those great results you are getting Sharon. I love that you go to these measures to make the best inputs you can. Well done. The proof is in the produce as keen gardeners say. Thanks for you input here.

  • Joe Lamp'l says:

    Thanks Abeer. I’m sorry to hear about your root knot nematode problems. That is a hard problem to solve. I will include this question in my follow up with Dr. Ingham. Thank you.

  • Joe Lamp'l says:

    Consider this on the list, Darby! Thanks for a great question.

  • Joe Lamp'l says:

    Including this Jeremiah in my list to ask Dr. Ingham. Stay tuned.

  • Joe Lamp'l says:

    Hi, Bren. If it doesn’t smell and looks rich, dark and soil-like or weill on the way, as leaves, you can be fairly confident that you’re not dealing with the risk associated with a cocktail mix of strange inputs that could lead to problems.
    Personally, I lived in a town that offered composted leaves only from their municipal pick ups. I loved this material and used it for years with great results. I never had it tested nor did I ever suspect it was a problem. The rich, earthy texture and smell have me a good sense that I was dealing with quality compost. While that’s not a very sciency answer, when you consider all that you know about what’s in it, combined with it’s current physical state, you can make a pretty good educated guess.
    However, if you wanted to really now, I would send samples to your state university soil lab, perhaps through your county extension service, or you could google private soil labs and send a sample there. Just be sure in either case you have them test for what you want to know.

  • Joe Lamp'l says:

    I will ask Dr. Ingham, Lynn. I don’t use it personally so I cannot add anything from my experience here.

  • Joe Lamp'l says:

    I will ask Dr. Ingham’s input but I would also add that closed bin systems like your tumbler tend to never get dry enough. You could turn it more and should, and add more carbon sources such as straw, shredded paper or leaves. That will help. And I agree with Jeremiah below. What you have is not aerated tea but simple compost leachate.

  • Forrest Jones says:

    Joe, just one more if it is not on your list already. I would like Elaine to discuss compost tea vs chemical soluble vs organic soluble. As a side note my big box go to has been out of Milorganite since late spring. That may be evidence of an unnamed influencers growing audience.

  • David Loszewski says:

    Thanks Joe! I think I answered my own question yesterday when I dug into my compost pile and pulled out a handful of earthworms! If they like it, then it must be good right? lol

  • David Loszewski says:

    Love Charles Dowding!!!

  • Joe Lamp'l says:

    Good to know. And you will also be happy to know he is our featured guest on an upcoming podcast in a few weeks. He’s awesome!

  • Bren O'Reilly says:

    Thank you for your reply. I believe the compost hits all of those criteria, though I may still get it tested.

  • Joe Lamp'l says:

    You got it, Forrest. I’ll make sure to include this. And sorry to hear about Milorganite being out where you are. I like your logic by the way as to the potential reason. Let’s just go with that. Here’s hoping you’ll have more MILO in your life soon, Forrest. Thanks.

  • Tim Bauerschmidt says:

    Elaine mentioned the use of cardboard in the compost, noting the micro organisms love the glue. That cleared up one of mh questions. How about the ink? Cereal, food boxes have a lot of ink and I would think that is a lot of chemical and toxins that you are adding to the soil, or is she reffering to just brown corrugated boxes. Could she also give more detail about the party food to get things going in the pile.

  • Tim Bauerschmidt says:

    Another question, my compost piles are about 8′ X 10′ X 6′ high at the end of summer. Grass added thru the mowing season, leaves in fall, and wood mulch from a local tree trimming service to make sure it is going though out the summer. With such a large pile, I tile it with a compact tiller to rotate it. Am I doing more damage than good to the food Web that is breaking get down my pile? I would also be interested in hearing opions on forking soil. I understand no till, but have seen where some people take a pitch fork, drive it straight down and move it just a bit to loose air passages and keep it from compacting. Is that even necessary. It sounds as if the healthy system that Elaine talked about is what is bringing the oxygen into the soil as part of the process.

  • Andrea Davies says:

    What does chelated iron do to the health of your soil (using it as a weed killer on lawns)

  • Sheila Manz says:

    I absolutely agree with you, David! I am a PhD Engineer myself and I LOVE science. I learned a ton listening to Dr. Ingham and I am very thankful she spent so much time sharing with us on these two podcasts (& thank-you Joe & team for enabling it all!!). My challenge is what to do with all this info as a home gardener that doesn’t have a microscope with built-in internet-connected camera.I actually felt scared that somehow I was doing everything wrong in my garden since clearly there is a lot that can go wrong if you don’t do some basic things.Perhaps on the follow-up interview, Dr. Ingham can walk through something like a top 5 of what to do in a home garden to maintain soil health. Then we can at least have something more concrete to take away? I did hear some concrete steps (e.g. turn compost) but perhaps boiling it down into a list would help us mortals out! THANK-YOU!!!!

  • ryan korkowski says:

    Could one substitute rich forest floor humus for compost in an aerated tea?
    I am eager to get the ball rolling on reviving some land, but haven’t yet found anyone local enough with adequate enough compost…
    I would follow Elaine’s Basic Compost Tea Recipe, as posted on Lexicon of Food’s site. (I would extract my own humic acid, but do not plan on including kelp or fish goop this initial batch)
    *The forest has not seen a plow in the last century, judging by the six foot wide white willow trees that serve as centuries around the perimeter of the wooded area!
    The woods are directly adjacent to the dead dirt field that we are going to attempt to revive, and the soil is
    chocolatey, fluffy, and earthy smelling for deeper than the 3′ my little trenching spade could reach! (the dirt field just yards away is compacted like a Walmart parking lot)
    *We just recently started a compost pile, and plan on making some more targeted tea recipes from the brewers manual once it is ready in a couple of weeks….
    By then we should be able to afford a microscope so we can be more informed on what we’re dealing with before we prepare our field for winter; which will be followed by its first no-till spring in several generations!!

  • Adam G says:

    Hello from Australia 🙂 I have two follow-up questions after your podcast with Dr Elaine Ingham.
    (1) If our soil is healthy, and the soil substrate has all the nutrients needed for a millennia, and only requires the microbes to turn them into a plant-available form, why are we told that we need to ‘replenish’ the soil, for example, in the spring, by putting more compost or other supplements on? Even if past crops have used up nutrients, shouldn’t the microbes be producing more from the crystalline structures of the bedrock etc?
    (2) I would love to hear of examples of Elaine’s methodology being successfully used in more hi-intensity market gardens and broad-acre cropping.

  • Joe Lamp'l says:

    I make sure this is clarified, Tim. But I can tell you the inks used today for this type of printing are vegetable-based, so not the chemicals and toxins of 30 years ago when inks contained a lot of metals. Thanks for your question.

  • Joe Lamp'l says:

    Hello, Adam! I love your question and I look forward to hearing what Dr. Ingham has to say in response when we put these to her for an upcoming follow up podcast.Until then, I’ll add my thoughts. Even though all the nutrients may be in the substrate, they are not accessible in solid form to be utilized by plant roots. They have to be converted into a soluble form over time from the microorganisms doing that work. The addition of new compost and organic matter provides important replenishment that existing and new bacteria, fungi and other soil-dwelling organisms need to keep the soil foodweb fully functioning to access and unlock mineralized nutrients. The new inputs are fuel for the engine to keep it running at peak efficiency.I’ll be sure to add your question so we can her what Elaine will say. Thanks for your question.

  • Emma M Thompson says:

    Hi Joe and Dr Ingham. Thanks for another fascinating podcast.I have a few questions I’m hoping you could follow up on, in regards to watering and the soil food web. In most places, tap water contains either chlorine or chloramines or both to discourage bacterial growth in the water supply. Is this enough to upset the soil food web if someone relies on tap water for their garden?If it is a problem, what do you recommend for people who just can’t collect enough rainwater for a years supply?

  • Joe Lamp'l says:

    Thank you, Emma. I will def. include this question in the follow up podcast, date TBD but should be December.

  • Emma M Thompson says:

    Just a side note for those interested in using cardboard in their compost heap/worm farm. Last year I invested in a 20 sheet cross cut paper shredder. Despite saying it won’t work with cardboard it shreds most of my cardboard into little strips. It works like a dream and composts down really quickly. I haven’t burnt it out yet and it’s been almost a year now! I’d highly recommend investing in one!

  • Craig says:

    What can you do to regenerate compost that has been left out too long in dry conditions and sun? I have a 2 ft tall pile of old compost that I left in the sun in AZ for 1 year. It was covered for maybe 1/2 of that.

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