Simple Potting Mix

[Thighland]

I'd like to detail a simple potting mix I'm getting decent results with. If anyone has suggestions for amendments feel free to add.
1 part rice husks
1 part well rinsed coco
1 part worm castings

To this I add a little powdered seaweed extract and biochar compost. The mix works well with seedlings, I've yet to use it on larger plants. I'd like suggestions for inputs for larger plants and especially for flowering plants.

 

[Creeperpark]

Since a plant is always taking nutrients from the soil you are going to have to add a little something back to make up for it. You can do that a few ways, one way is "top dress", and another to "spike", or deliver nutrients via the "water" route. If you are using an Ec meter you can measure the unused salts or the nutrient ppm to get failed in. Either way, be careful adding stuff until you learn what's too hot and what not.

 

[St. Phatty]

Not enough Natural humus.

Where do the 55+ different bacteria that make up a soil culture come from ?

The earthworm castings are good but they do not replicate a healthy soil, which has mycorrhizae etc.

One option is to hike in somewhere near your grow site and find natural healthy soil, and just take a cubic foot of it.

Of course, then it will also have bugs, including possibly mites.

 

[Thighland]

Thanks, the worm castings are only fed cow manure, so there are definitely elements missing. There's also bio char which was composted with chicken manure.

I spray with EM mixed with aquaponic water, which is full of microbes. Not sure if this does anything though

I've added soil in the past, hoping it would add minerals and bacteria. If you have any suggestions pls let me know. Not everything is available here, so I'm trying to keep it as simple as possible.

 

[Creeperpark]

I hear people say from time to time that there's no need for EC meter with organic grows. I disagree completely because they're vital for monitoring the water. You say you are limited so you will have to do with whatever you got. Good luck and keep us posted.

 

[St. Phatty]

Maybe if I use the soil as packing material for Books,
I can get the book shipping rate from the Post Office -
when I ship soil ?

 

[KIS]

I'd like to detail a simple potting mix I'm getting decent results with. If anyone has suggestions for amendments feel free to add.
1 part rice husks
1 part well rinsed coco
1 part worm castings

To this I add a little powdered seaweed extract and biochar compost. The mix works well with seedlings, I've yet to use it on larger plants. I'd like suggestions for inputs for larger plants and especially for flowering plants.

I have a feeling your pH will be too high based off your ingredient list. Also I find rice hulls to be poor as a primary aeration source. They are also troublesome for heavy metals depending on how the rice was grown (Arsenic).

 

[Thighland]

I have a feeling your pH will be too high based off your ingredient list. Also I find rice hulls to be poor as a primary aeration source. They are also troublesome for heavy metals depending on how the rice was grown (Arsenic).

Testing the run off the PH is fine, the plants grow well and are a very dark green under lights. However I have had problems with stems turning purple after a couple of weeks. This is about when I move them outside, then they become a lighter shade of green, possibly due to the strong sunlight.

The worm casting are made purely from cow manure, so there would be something lacking. My idea is to start as simple as possible, then add if necessary. The mix I'm testing now has chicken manure composted with biochar and garden soil. I think I'll get better results.

Googling shows that the local rice varieties I'm using contain the least amount of arsenic, according to the University of California.

I am a big fan of rice husks. They are similar to perlite, but a waste product, cheaper and better environmentally. I've used them in aquaponics, the seem to give the plants an initial boost which then slows. I think they may add nutrients to the mix.

For potting mix they are great, but in the soil they may tax N as they break down, not sure if this is a problem. They are a great mulch and add silica to the soil. I'd be interested in why you don't like them and what you prefer?

 

[KIS]

Testing the run off the PH is fine, the plants grow well and are a very dark green under lights. However I have had problems with stems turning purple after a couple of weeks. This is about when I move them outside, then they become a lighter shade of green, possibly due to the strong sunlight.

The worm casting are made purely from cow manure, so there would be something lacking. My idea is to start as simple as possible, then add if necessary. The mix I'm testing now has chicken manure composted with biochar and garden soil. I think I'll get better results.

Googling shows that the local rice varieties I'm using contain the least amount of arsenic, according to the University of California.

I am a big fan of rice husks. They are similar to perlite, but a waste product, cheaper and better environmentally. I've used them in aquaponics, the seem to give the plants an initial boost which then slows. I think they may add nutrients to the mix.

For potting mix they are great, but in the soil they may tax N as they break down, not sure if this is a problem. They are a great mulch and add silica to the soil. I'd be interested in why you don't like them and what you prefer?

I find rice hulls don't offer adequate porosity to the soil mix and break down in highly biologically active soils too quickly, leaving you with a potentially mucky soil mix with poor drainage unless you have another aeration type in the mix. If you are re-using your soil mix for successive runs, then arsenic is definitely something you need to watch for because it's only source of removal from the soil is into plant biomass.

I agree that rice hulls are a better choice from a sustainability perspective IF they are sourced locally and not being shipped from Asia with a large fossil fuel cost. I wouldn't trust google personally for what the actual As content in the rice hulls you're using actually is.

Cow manure is probably my least favorite "manure" source based on the nutrient profiles you tend to get out of it. I like the idea of supplementing with chicken manure, provided you're watching your N levels.

Your purpling stems could be related to cold root temperatures or a lack of available P in your soil.

 

[Thighland]

I find rice hulls don't offer adequate porosity to the soil mix and break down in highly biologically active soils too quickly, leaving you with a potentially mucky soil mix with poor drainage unless you have another aeration type in the mix. If you are re-using your soil mix for successive runs, then arsenic is definitely something you need to watch for because it's only source of removal from the soil is into plant biomass.

I agree that rice hulls are a better choice from a sustainability perspective IF they are sourced locally and not being shipped from Asia with a large fossil fuel cost. I wouldn't trust google personally for what the actual As content in the rice hulls you're using actually is.

Cow manure is probably my least favorite "manure" source based on the nutrient profiles you tend to get out of it. I like the idea of supplementing with chicken manure, provided you're watching your N levels.

Your purpling stems could be related to cold root temperatures or a lack of available P in your soil.

I'm surrounded by rice fields, rice husks are very cheap. They are great for many things, including the GH floor. For aeration and drainage I love them, however I agree about them breaking down and I only use them extensively in pots for seedlings. When planting in beds, I use them as mulch, they stop weeds coming up and add silica to the soil when they break down.

Silica is important for cannabis stems, it is also why rice husks are useful for removing arsenic or preventing it from going into the rice. As I understand it the arsenic issue is more for rice than husks, as rice is eaten. Arsenic comes from groundwater, rice husk can remove it.

Cow manure has the most organic matter, but it's nutrient levels aren't great. The castings are bought and cow manure is the only readily available food for worms. Now I have my own worm bin, with a mix of manure and banana peel, which will be helpful for increasing K. Because I use aquaponic water, which is low in K.

What would you recommend long term to increase drainage and aeration in clay? I've found large chunks of coco good, but this still breaks down. My favorite is carbonized rice husks (biochar), which never breaks down and adds silica to the soil. Larger pieces of charcoal would also work well, but I've never tried it.

The new potting mix I'm trying has half the castings, with more nutrients coming from biochar compost.