I would avoid using any compost or worm castings in your potting mix. Both will continue to degrade and collapse/compress, reducing pore space and the ability of the soil to drain well.

My first choice would be to shoot for something like the 5-1-1 mix: 5 parts bark fines, 1 part peat or coir and 1 part perlite. If that is too much of a chore to locate all the ingredients and mix, a distant second choice would be to obtain a better quality bagged potting mix and add 25-30% perlite. Even better if you can add the bark, but if you can get that, just go with the 5-1-1 formulation.

Not sure what you might be growing but any liquid or water soluble all purpose fertilizer should work adequately for most plants. I and many other container gardeners favor the Dyna Gro products but Miracle Gro will work as well. And if you are vermicomposting, the leachate from the worm bin is great to add......just not the castings themselves :-)

Thanks.

Whatever is reasonable price and easy to aquire. Home depot does not carry Bark fines at my local store.

Bark fines online is expensive and sold by quart. I was hoping to use coco coir as main ingredient to cut on costs and less heavy lifting, being on 2nd floor.

Even small quantity of worm castings is bad?

The perlite would not help?

I guess it is back to using miracle grow potting mix.

Mostly for fig trees, Chilli Peppers and few leafy greens. Couple citrus trees.

You could try looking for bark fines at your local garden center as well. Or use Repti-bark, available at most pet supply places. Mini orchid bark works as well.

The coir absorbs a lot of water, as does peat. If you are concerned about weight, a fully saturated container with either a predominately peat or coir base will weigh more than the same container filled with a mix that is primarily bark based.

You can use the MG soil if that is what you prefer although not the best option. Just cut it heavily with another 25-30% by volume of perlite to help to maintain porosity and proper aeration.

Great explanation Richard. Makes sense.

So there is no cheaper sustainable equivalent to bark fines?

My confusion is ‘Compost’. Almost every website and youtube talks about adding 1-2 parts compost to the potting mix recipe.

Then it says to add worm castings. The pot mix you mentioned is ver similiar to then what is used in hydroponics, just a medium to hold the plant in place, establish roots and using your own nutrients.

I will check pricing for bark fines. This too

decomposes in time...?

You really need to spend some time on the Container Gardening forum reviewing discussions about potting media. And thoroughly review this long running thread: Container Soils - Water Management and Retention. It will explain in detail why compost or other heavily organic ingredients are not advised.

And it is important to understand the source of the info that recommends compost. In the UK, 'compost' just refers to potting soils, not to the decomposed garden and kitchen waste scraps we here in the US consider compost. (well, it also refers to that as well, but you can figure out the diffference by the context). That can be very confusing :-)

And yes, the bark fines will decompose over time....but a long time and your potting soil will have been replaced several times before that comes anywhere close to happening!

Yes, I am spending time reading up on the link you sent.

Look here:

https://www.houzz.com/magazine/how-to-grow-vegetables-in-containers-stsetivw-vs~24753545

His mix is organic material in container. Again, mentioning compost(not potting mix).

Trial and error then...

The pine bark fines are also sold as something called soil conditioner. I noticed neither Home Depot or Lowe's carried them last year, replacing them with coir but perhaps you could inquire at your store. It wasn't expensive. Places that sell mulch have them and may sell you a smaller amount.

First, regarding the vegetables in containers link - that mix is going to be very heavy because of the sand. Those containers will be hard to move. What the sand in that mix does do is help balance out the acidic coir. And the compost will have no value in the mix other than as a soil conditioner - and a poor one at that because it will continue to decompose.

Second, worm castings aren't going to hurt anything, but they don't have the value in your containers that they have in your garden soil. Since they are expensive, I would save them for digging in around the vegetables, flowers or rose bushes. Containers are a synthetic environment - just like the hydroponics you mentioned. Treat the plants as if they are in a lab. It is a very different mindset to get in to if you are used to organic gardening.

Finally, I make 5-1-1 mix for my containers. No, I haven't found Pine Bark Fines, either. I guess they exist as a commercial product somewhere, but not near me. Pine Bark Fines are pieces of pine bark about 3/8" in diameter (just under 1/2 inch size). Here are the alternatives I have found.

Repti Bark - This is a pet bedding sold on Amazon and in pet stores. It is expensive compared to potting soils, but if you are just doing a few pots it might be reasonable. The pieces are just a bit bigger than the ideal, but close enough. (And, most importantly, it requires no additional work to make the container mix.)

Pine Bark Mulch - (not Pine Bark Nuggets - which are too big) Most big box stores and garden centers sell this. The challenge is that, depending on the manufacturer, it will contain pieces that vary from a couple of inches, to bark dust. You will have to screen to get the 3/8" particles you desire. I use wire fencing rolls. The first has 1/2" openings stretched out over a wheelbarrow. This screens out about 1/2 the contents of the bag which are big chunks of bark (which I use as mulch in front-yard flower beds and to spread on garden paths). The smaller stuff (pine fines and pine dust) falls into the wheelbarrow. Next, I sift that through 1/4" wire. This keeps the fines on the surface, and lets the dust fall into the wheelbarrow. The pine bark fines go into my 5-1-1 mix and the dust goes into compost (or just spread it on your garden beds or lawn). Whew! That's a lot of work. My back hurts just thinking about it.

Note - less than 25% of the bag will be fines. So unless the big pieces you are sifting out also have value to you, the pine bark fines themselves are costing you 4x the cost of the bag plus your labor sifting them out. Maybe now the expensive bag of Repti Bark seems like more of a bargain.

Thanks Richard.

I am getting some MG Pine Bark and will try the 5-1-1 mix.

Just wish there was some alternative to pine bark which is not cheap

and hard to find.

I live in the So. CA area and one can find the pine barks for the 511 pot mixture at Armstrong Garden Centers. I haven't purchased for awhile but I believe they are still available. They are called micro barks.

Be aware that if you read any websites or view any videos made by U.K. gardeners the term 'compost' has two meaning over here. Both the stuff you make in a compost heap and as a catch all term for any planting mix eg 'houseplant compost' etc. Not sure if Oz and NZ use it the same way.