Also, I'll be using one of the pots for banana peppers and thai hot peppers. I want to transplant my current peppers plants to a larger container so they will be bigger and healthier. How many do you think I could fit into a 20 gallon nursery pot without causing problems?

I have to tell ya......it would be a whole lot easier - and cheaper - to purchase a premixed blended organic fert. Espoma, Dr. Earth or Fox Farms are popular organic labels you can purchase online or at retailers across the country. If you want a liquid, I'd recommend Neptune's Harvest or fish/seaweed emulsion. The above can be obtained as or are intended as all purpose formulations - can be used on any type of plant under pretty much any growing conditions. But until you have a soil test done, you don't know what you need or in what concentrations. Until then, this is all just speculation. FWIW, just adding compost annually and using a cover crop will typically provide all the nutrients your garden requires, skipping the need for any added fertilizers.

It's both, acts to provide some moisture and fertilizer retention, and also a bit more air space. All by itself bark does not provide enough of anything to really support plant life (except for possibly orchids), but once it is mixed with peat moss - bark fines help extend the âÂÂlifeâ of the potting mix by being relatively slow to break down. It's helpful in container mediums for perennials, woody plants - I don't see benefit to adding it to your short use seed starting combination - I do like a container medium that is bark based for things like hydrangeas if growing those long term in pots. I have sweet box in containers at my entryway in bark based medium, it supports those well but they are supplemented with a (half strength) liquid fertilizer occasionally.

Well, if you were going for "airy and fast draining", I'm sorry to say you missed the mark :-( Initially, your mix may exhibit these qualities but once you have watered the potted plants a few times, that mix will begin to compress and collapse and the perched water table will slowly climb higher and higher. One of the critical elements of growing anything successfully in a container beyond just good drainage is porosity and how that contributes to aeration or the ability of water, oxygen and nutrients to move through the soil. Porosity describes the voids between the various particles that comprise the mix and is established and maintained by both by particle size and by the permanence of the particles, specially things like perlite, grit or calcined clay products, which do not lose size or shape over time. In contrast, your mix is predominately is very finely textured material: the garden soil, the worm castings, peat. And the compost - if not finely textured when added - will quickly become so as it continues to degrade and breakdown in the mix. Will it work?? Of course it will - plants can grow in just about anything - but it is far from ideal and you will have to pay very close attention to watering. Your mix will be neither fast draining nor offering adequate porosity and the risk of over watering and consequential root rots is very high. There is a great deal of science behind a well functioning container potting soil and everything you know about growing plants in the ground and what they need in that environment can be thrown out the window when dealing with containers. The two situations are vastly different and what works well in the ground does not work the same in a container. No garden soil, no compost, no worm castings and generally even minimal amounts of peat or coir. No rocks or gravel on the bottom. I could go on and explain in more detail why these materials do not work well and what you should be striving for when creating a container soil mix but it's all been done before and by someone much more informed and skilled than I and summed up in this thread from the Container Gardening forum: Container Soils - Water Movement and Retention. It is long and slightly technical but it is well worth reading thoroughly and taking into sincere consideration.