Rice Hulls (CRH)

[tvanmunhen]

Hi everyone,


I'm exploring sustainable growing methods for cannabis and came across the idea of using carbonized rice hulls (CRH) in soil mixes. As we all know, cannabis plants need good aeration, water retention, and nutrient balance. Traditional growing mediums often use peat, but it's not the most eco-friendly option. Carbonized rice hulls (also called biochar) seem to be a great alternative, but I'm curious to hear your thoughts and experiences using it in cannabis cultivation.


Here's a bit of what I've gathered so far:


What are Carbonized Rice Hulls (CRH)?

• Rice hulls are the outer shells of rice grains that are typically discarded after harvesting. When they undergo pyrolysis (a heating process in the absence of oxygen), they become carbonized and are referred to as biochar.
• This process makes rice hulls more stable, increasing their ability to retain water and nutrients while improving soil aeration.

Benefits for Cannabis Cultivation:

1. Improved Aeration: CRH has a porous structure that can enhance root oxygenation and prevent soil compaction, which is critical for healthy cannabis root systems.
2. Enhanced Water Retention: While cannabis prefers well-draining soil, water retention is key during the dry stages. CRH can hold moisture while allowing excess water to drain, maintaining the right balance.
3. Nutrient Retention: CRH helps retain nutrients, reducing the need for frequent feeding. This is especially beneficial in organic growing systems where nutrient release is slow.
4. Soil pH Adjustment: CRH has a neutral to slightly alkaline pH, which can help balance acidic soils and keep it within the ideal pH range for cannabis (6.0-7.0).
5. Sustainability: Rice hulls are an agricultural waste product, so using them in cannabis cultivation reduces waste and minimizes environmental impact.

Drawbacks/Considerations:

• Application Method: While CRH can be mixed into soil or used as a top dressing, it might require proper pre-treatment or activation to maximize its benefits.
• Cost and Sourcing: Biochar can be a bit pricey depending on your location, and sourcing good-quality carbonized rice hulls might be difficult for some growers.
• Overuse: Like anything, moderation is key. Using too much CRH could lead to water retention issues if the balance isn't right.

Questions for the Forum:

• Have any of you used carbonized rice hulls in your cannabis grows?
• If so, what benefits or challenges have you noticed?
• What are your preferred application methods for mixing CRH into your soil or growing system?
• Any tips for sourcing CRH or making it yourself?

Looking forward to hearing your experiences and thoughts on this.

 

[Bareback]

Hi everyone,


I'm exploring sustainable growing methods for cannabis and came across the idea of using carbonized rice hulls (CRH) in soil mixes. As we all know, cannabis plants need good aeration, water retention, and nutrient balance. Traditional growing mediums often use peat, but it's not the most eco-friendly option. Carbonized rice hulls (also called biochar) seem to be a great alternative, but I'm curious to hear your thoughts and experiences using it in cannabis cultivation.


Here's a bit of what I've gathered so far:


What are Carbonized Rice Hulls (CRH)?

• Rice hulls are the outer shells of rice grains that are typically discarded after harvesting. When they undergo pyrolysis (a heating process in the absence of oxygen), they become carbonized and are referred to as biochar.
• This process makes rice hulls more stable, increasing their ability to retain water and nutrients while improving soil aeration.

Benefits for Cannabis Cultivation:

1. Improved Aeration: CRH has a porous structure that can enhance root oxygenation and prevent soil compaction, which is critical for healthy cannabis root systems.
2. Enhanced Water Retention: While cannabis prefers well-draining soil, water retention is key during the dry stages. CRH can hold moisture while allowing excess water to drain, maintaining the right balance.
3. Nutrient Retention: CRH helps retain nutrients, reducing the need for frequent feeding. This is especially beneficial in organic growing systems where nutrient release is slow.
4. Soil pH Adjustment: CRH has a neutral to slightly alkaline pH, which can help balance acidic soils and keep it within the ideal pH range for cannabis (6.0-7.0).
5. Sustainability: Rice hulls are an agricultural waste product, so using them in cannabis cultivation reduces waste and minimizes environmental impact.

Drawbacks/Considerations:

• Application Method: While CRH can be mixed into soil or used as a top dressing, it might require proper pre-treatment or activation to maximize its benefits.
• Cost and Sourcing: Biochar can be a bit pricey depending on your location, and sourcing good-quality carbonized rice hulls might be difficult for some growers.
• Overuse: Like anything, moderation is key. Using too much CRH could lead to water retention issues if the balance isn't right.

Questions for the Forum:

• Have any of you used carbonized rice hulls in your cannabis grows?
• If so, what benefits or challenges have you noticed?
• What are your preferred application methods for mixing CRH into your soil or growing system?
• Any tips for sourcing CRH or making it yourself?

Looking forward to hearing your experiences and thoughts on this.

I’ve been making biochar for years. Not with rice hulls but with wood . I inoculate it with worm castings. And I cook my soil for 4-6 weeks before use or in my case re-use . I also use mycos and all the nutrients to revitalize the soil and I have great results. Of course I watch for any nutrition deficiency and add a salt fertilizer for quick fix or organic fertilizer for a slower more long term fix .

I read that a golf ball size of charcoal has the same surface area as a tennis court. I don’t know if it is true but it’s a lot of surface for micro organisms to flourish.

Plus I get all my material for free so I make a lot of high quality lump charcoal for grilling and I use the crumbs to make biochar….so much so that I can use it in my veggie garden. It blows people away when they see the yield.

 

[tvanmunhen]

I’ve been making biochar for years. Not with rice hulls but with wood . I inoculate it with worm castings. And I cook my soil for 4-6 weeks before use or in my case re-use . I also use mycos and all the nutrients to revitalize the soil and I have great results. Of course I watch for any nutrition deficiency and add a salt fertilizer for quick fix or organic fertilizer for a slower more long term fix .

I read that a golf ball size of charcoal has the same surface area as a tennis court. I don’t know if it is true but it’s a lot of surface for micro organisms to flourish.

Plus I get all my material for free so I make a lot of high quality lump charcoal for grilling and I use the crumbs to make biochar….so much so that I can use it in my veggie garden. It blows people away when they see the yield.

That's very interesting thanks! I will probably do some of that for my outdoor garden this year. Thanks for the idea.

I Bought a bail 3' or so in diameter of Rice hulls for $15. I use it for aeration in my soil. I also use it as to help retain moisture on the top layer of soil. I will never need more rice Hulls for many years lol.

Trying to figure out some fun, useful ways to grow in it since it's so cheap and light. I read somewhere CRH are commonly used for rooftop gardening due to their light weight and ability to retain some water. Not to mention the microbiology benefits.

 

[DCcan]

You can use the old pellets from your carbon filters also, thats bamboo biochar. (or pressed coal pellets if it's a bargain filter from xyz )
Innoculate it with some worm castings, or add some wild mykos from rotting stump/leaf pile.
Might want to consider nematodes if going with soil indoors, cut down on the crawlies.

 

[tvanmunhen]

You can use the old pellets from your carbon filters also, thats bamboo biochar. (or pressed coal pellets if it's a bargain filter from xyz )
Innoculate it with some worm castings, or add some wild mykos from rotting stump/leaf pile.
Might want to consider nematodes if going with soil indoors, cut down on the crawlies.

I need to find my carbon filters. I stopped using them a couple years ago and buried them in the garage. I might do nematodes again they worked out for me before with thrips.

Hopefully I don't get crawlies I hate it when that happens.

 

[tvanmunhen]

Making carbonized rice hulls (CRH) at home can be done in small batches with a few simple steps. Here's an easy guide for the process:

### Materials Needed:
- Rice hulls (can be sourced from a local supplier or your own rice milling)
- A metal container (like a metal drum or steel pot with a lid)
- A heat source (such as a propane torch or campfire)
- A thermometer (optional, but useful to monitor temperature)

### Steps:

1. **Prepare the Rice Hulls:**
- Gather dry rice hulls. Make sure they are free of contaminants like dirt or stones.

2. **Set Up a Containment Vessel:**
- Use a metal container with a lid (like a large steel pot, metal drum, or even a small metal barrel). This will be used to contain the rice hulls and allow them to heat up without direct contact with air (which could cause them to burn instead of carbonize).

3. **Fill the Container:**
- Fill the container about halfway with rice hulls. You want to leave some space for air to circulate around the rice hulls during the heating process.

4. **Heat the Container:**
- Place the container over a heat source like a propane torch or a small campfire. If you’re using a campfire, ensure you can control the flame and not let it get too hot. The key is to heat the container slowly without letting it reach too high of a temperature. Ideally, you want the temperature to reach around **300°C to 500°C** (572°F to 932°F).

5. **Monitor the Process:**
- Keep the lid on the container while heating. The rice hulls should begin to release smoke, which is an indication of pyrolysis (the process of heating organic material in the absence of oxygen).
- You’ll want to maintain a low level of oxygen so the rice hulls carbonize instead of burning completely. It may take about 30 minutes to an hour for the rice hulls to turn into biochar.

6. **Cool Down:**
- Once the rice hulls have darkened and become crispy, remove the container from the heat source and let it cool down completely. **Do not open the container while it’s still hot**, as this can lead to dangerous flare-ups.

7. **Check the Biochar:**
- After cooling, you should have your carbonized rice hulls (biochar). The material should be black, light, and porous.

8. **Use the CRH:**
- Now you can mix the CRH into your soil, use it as a water retention agent, or even incorporate it into composting.

I'm going to be making these soon, feel free to try out these steps yourself and post up some results here.

Thanks in advance for any of your contribution to this CRH thread.

 

[Bareback]

Making carbonized rice hulls (CRH) at home can be done in small batches with a few simple steps. Here's an easy guide for the process:

### Materials Needed:
- Rice hulls (can be sourced from a local supplier or your own rice milling)
- A metal container (like a metal drum or steel pot with a lid)
- A heat source (such as a propane torch or campfire)
- A thermometer (optional, but useful to monitor temperature)

### Steps:

1. **Prepare the Rice Hulls:**
- Gather dry rice hulls. Make sure they are free of contaminants like dirt or stones.

2. **Set Up a Containment Vessel:**
- Use a metal container with a lid (like a large steel pot, metal drum, or even a small metal barrel). This will be used to contain the rice hulls and allow them to heat up without direct contact with air (which could cause them to burn instead of carbonize).

3. **Fill the Container:**
- Fill the container about halfway with rice hulls. You want to leave some space for air to circulate around the rice hulls during the heating process.

4. **Heat the Container:**
- Place the container over a heat source like a propane torch or a small campfire. If you’re using a campfire, ensure you can control the flame and not let it get too hot. The key is to heat the container slowly without letting it reach too high of a temperature. Ideally, you want the temperature to reach around **300°C to 500°C** (572°F to 932°F).

5. **Monitor the Process:**
- Keep the lid on the container while heating. The rice hulls should begin to release smoke, which is an indication of pyrolysis (the process of heating organic material in the absence of oxygen).
- You’ll want to maintain a low level of oxygen so the rice hulls carbonize instead of burning completely. It may take about 30 minutes to an hour for the rice hulls to turn into biochar.

6. **Cool Down:**
- Once the rice hulls have darkened and become crispy, remove the container from the heat source and let it cool down completely. **Do not open the container while it’s still hot**, as this can lead to dangerous flare-ups.

7. **Check the Biochar:**
- After cooling, you should have your carbonized rice hulls (biochar). The material should be black, light, and porous.

8. **Use the CRH:**
- Now you can mix the CRH into your soil, use it as a water retention agent, or even incorporate it into composting.

I'm going to be making these soon, feel free to try out these steps yourself and post up some results here.

Thanks in advance for any of your contribution to this CRH thread.

If you have a propane or charcoal grill it would be very is to use a cookie tin to make biochar. I use the “ top lit down draft “ method. I use a converted 30-40 gallon water heater tank ( it takes a little modification ) for my charcoal chamber and a 55 gallon drum for the fuel chamber . Using oak for the charcoal and pretty much anything I want to for fuel , I make really nice lump charcoal the kind that has a glass tinkling sound when you drop it. I make the biochar from scraps ( pieces that are to small or get broken ) .

I’m happy to film the whole process for everyone to see. I have about three hundred pounds of charcoal now but will make 5-6 hundred more pounds this summer so if any one wants to see it let me know. I can also demonstrate small batching at the same time.

I have 0$ tied up in my operation but one could easily spend a few dollars if they weren’t as resourceful. I think you are dead on with wild mycos .

Y’all just let me know if I help in any way.

 

[tvanmunhen]

If you have a propane or charcoal grill it would be very is to use a cookie tin to make biochar. I use the “ top lit down draft “ method. I use a converted 30-40 gallon water heater tank ( it takes a little modification ) for my charcoal chamber and a 55 gallon drum for the fuel chamber . Using oak for the charcoal and pretty much anything I want to for fuel , I make really nice lump charcoal the kind that has a glass tinkling sound when you drop it. I make the biochar from scraps ( pieces that are to small or get broken ) .

I’m happy to film the whole process for everyone to see. I have about three hundred pounds of charcoal now but will make 5-6 hundred more pounds this summer so if any one wants to see it let me know. I can also demonstrate small batching at the same time.

I have 0$ tied up in my operation but one could easily spend a few dollars if they weren’t as resourceful. I think you are dead on with wild mycos .

Y’all just let me know if I help in any way.

Would be great to see that process thanks! Any pics, videos or ideas are welcome.

I am most likely going to use one of my cast iron Dutch ovens and some briquettes. Possibly #10 food cans in the pellet grill covered with foil. I will do a bunch of small batches and mess around.

 

[Bareback]

Would be great to see that process thanks! Any pics, videos or ideas are welcome.

I am most likely going to use one of my cast iron Dutch ovens and some briquettes. Possibly #10 food cans in the pellet grill covered with foil. I will do a bunch of small batches and mess around.

If at first you don’t succeed try again…..like literally…. if the pyrolyses isn’t complete, fire that mother again.

I have no experience with rice hulls so I’m not familiar with the moisture content. With wood moisture content means everything. Also the higher the moisture content the more liquid gas will be extracted and that will need a way to escape the charcoal chamber. I simply load my chamber and turn it upside down where there’s a small hole for it to escape. But no other holes in that chamber because if it ignites , even if it is only smoldering it will burn up completely. Also when it is still hot never open it…. charcoal dust + ignition source = something bad .

 

[tvanmunhen]

If at first you don’t succeed try again…..like literally…. if the pyrolyses isn’t complete, fire that mother again.

I have no experience with rice hulls so I’m not familiar with the moisture content. With wood moisture content means everything. Also the higher the moisture content the more liquid gas will be extracted and that will need a way to escape the charcoal chamber. I simply load my chamber and turn it upside down where there’s a small hole for it to escape. But no other holes in that chamber because if it ignites , even if it is only smoldering it will burn up completely. Also when it is still hot never open it…. charcoal dust + ignition source = something bad .

It sounds like an interesting process. I want to see pics of your Chambers. I enjoy burning brush and that sounds like something that could be whip up pretty easy. Have you ever done pine cones and pine limbs? I have lots of those laying around.

Thanks for the important safety tips. I have read to be careful of hot gas igniting. The lack of oxygen is important for the carbonization process so use a canister with a lid. When I heard that I instantly thought ooh a bomb.

So That's why I was thinking the Dutch oven would work in small batches. Hopefully it doesn't ignite through the lid. Or make my Dutch oven tastes like burnt rice forever.

Going to lay it on a bed of coals and put a few on top. I will try to get it around 800° for about 40 minutes then brush away all the coals and allow it to cool.

Figured with the pellet grill, long as if I don't open the barbecue lid until everything cools it should be fine . The number 10 food cans will be cooked at 500° for 2 hours. I also may try sheet pans covered in foil in a bbq.

Anyhow, really appreciate the advice and feedback. Even though it's not rice hulls it is very useful and helpful. Maybe I should just change the title to carbonized gardening questions and growing.

Cheers

 

[tvanmunhen]

If any of you dolls out there are doing carbonized anything you can share it here. This will be open to all.

Post pics, questions or ideas for carbonized gardening. There is a wide variety of ways to use biochar. And like me, I'm sure a lot of you have questions.

It will be nice to have a place where people can learn from each other and share from their experiences.

Thanks!

 

[DarkWeb]

I've made char cloth before but never anything for gardening.

 

[Bareback]

This is all the components. The inner chamber and base ( for the charcoal ) , the outer chamber and chimney cap ( for the fuel ).
The wood stack with a combination of fist sized pieces and smaller. I use these to make lump charcoal for grilling.

Inner chamber is loaded ready to install base and invert.

These are some of smallest pieces, I use these to make the biochar.
Outer chamber is packed with fuel and ready for the chimney cap , time to light it up and throw the cap on.
I’ll open tomorrow and show the results.

 

[Bareback]

Some potatoes growing in a mix of compost and biochar. With a splash of spring time for color. The azaleas are 135 years old .

 

[tvanmunhen]

View attachment 3752
This is all the components. The inner chamber and base ( for the charcoal ) , the outer chamber and chimney cap ( for the fuel ). View attachment 3753
The wood stack with a combination of fist sized pieces and smaller. I use these to make lump charcoal for grilling.
View attachment 3755
Inner chamber is loaded ready to install base and invert.
View attachment 3754
These are some of smallest pieces, I use these to make the biochar. View attachment 3756
Outer chamber is packed with fuel and ready for the chimney cap , time to light it up and throw the cap on. View attachment 3757
I’ll open tomorrow and show the results.

This is all great stuff! Thanks for sharing. I think you've inspired me to mess around even deeper down this rabbit hole LOL.

 

[Bareback]

This is all great stuff! Thanks for sharing. I think you've inspired me to mess around even deeper down this rabbit hole LOL.

I don’t fire it up when it’s dry and/or windy. Have to be responsible you know.

I found lots of videos on making biochar on yt .

 

[tvanmunhen]

Biochar helps balance pH levels in soil through several key mechanisms. Here's how it works:

1.​

• Most biochar, including carbonized rice hulls, has an inherently alkaline pH due to the materials used (like rice hulls) and the pyrolysis process. When biochar is added to acidic soils (low pH), it raises the pH, making the soil less acidic and more neutral or slightly alkaline.

2.​

• Biochar has a strong buffering capacity, meaning it can absorb and release hydrogen ions (H+) in response to changes in the surrounding environment. When the soil is too acidic, biochar can adsorb excess hydrogen ions, reducing acidity. Conversely, in soils that are too alkaline, biochar can release certain minerals and components that help to lower the pH.

3.​

• The surface of biochar contains a variety of functional groups, such as carboxyl (–COOH) and phenolic (–OH) groups. These functional groups can act as weak acids or bases, which interact with soil components to moderate pH fluctuations. In acidic conditions, the biochar can act as a base to neutralize acidity. In more alkaline conditions, it can help buffer the pH to prevent it from becoming too high.

4.​

• The pH of the soil affects microbial activity, as different microorganisms thrive at specific pH levels. By balancing the pH, biochar creates a more favorable environment for soil microorganisms, which further promotes nutrient cycling and supports healthy plant growth.

5.​

• Biochar has a high cation exchange capacity (CEC), meaning it can exchange positively charged ions (cations) like calcium (Ca²⁺), magnesium (Mg²⁺), and potassium (K⁺). These ions can help neutralize soil acidity and stabilize the pH. For example, calcium carbonate in the biochar can directly raise the pH when needed.

6.​

• Unlike some soil amendments that may degrade or leach out over time, biochar is stable and can persist in the soil for hundreds to thousands of years. This long-lasting presence means that biochar can continuously maintain a more stable pH over time, providing ongoing benefits to soil health.

 

[tvanmunhen]

This will be my first attempt at making CRH. I filled two aluminum trays and tightly covered them with foil.
I'm putting them in the pellet smoker for 3 hours at 500° because that's as high as my smoker will go. I plan on giving each pan a shake on every hour to mix up the contents.

I will report back when it's done.

 

[tvanmunhen]

3 hours later I pulled the trays out. I allowed them to cool for 30 minutes before opening.
I gave both pans a shake each hour through the cooking process. Each time I did, I could see little plumes of smoke coming out. Probably not the cheapest option to make CRH but I like how it turned out.

I'm going to make more while I'm waiting for seeds to sprout. Going to use the same stuff only change it to 2 hours with a few shakes in the cooking process.

 

[Bareback]

3 hours later I pulled the trays out. I allowed them to cool for 30 minutes before opening.View attachment 3896
I gave both pans a shake each hour through the cooking process. Each time I did, I could see little plumes of smoke coming out. Probably not the cheapest option to make CRH but I like how it turned out.
View attachment 3895
I'm going to make more while I'm waiting for seeds to sprout. Going to use the same stuff only change it to 2 hours with a few shakes in the cooking process.

As you pick it up and drop it, does it have a new sound…..kinda like tinkling similar to the sound of broken Christmas ornaments. And does it have a shimmer like a iridescence….. in a strange way it has a color that makes a sound.

I’ll try to make a video of what I mean in the next few days.