1.25 cups in a 20 gal isn't excessive. Yes, mix it in well. No need to moisten first, but water well after you're all planted. If you ever forget like I do sometimes to mix in the initial CRF application, then just sprinkle a little bit on top of the 5-1-1 surface in the pot and mix it into the first inch or two. Then remember to apply more in a couple of months as the weather heats up. Light and more frequent always preferred in pots over heavy and infrequent fertilizing. Also, with 5-1-1, there isn't really a transplant hole and backfilling. That's why you confused me. You make a volcano in the pot, splay out the bare plant roots and lay radially on top of the volcano. Then you fill in carefully doing your best to get mix in amongst the roots. You'll understand once you get your first planting under your belt.

Mostly azaleas, camellias , lorepetalums, fuchsias and camellias. Most of these prefer acid soils, so no lime. Do I still need gypsum though if it's in the fertiliser? Or would the quantities not be enough? I've had my plants potted up for about three months now and they seem to be growing well, it's just finished summer here in Australia and they've shown no signs of stress or lack of water. I'm still worried about the fact I haven't added anything except for the fertiliser periodically. What would be the signs of not having added gypsum?

The fertilizer you have is organic, and would probably be best suited for the ground where it could break down properly. Container fertilization when using a soilless mix is a bit different ballgame. If you use a liquid or water soluble chemical fertilizer the nutrients will be available immediately to the plant. Since your plants are very small they don't need very much fertilizer at all anyway. You can add a little fertilizer to the mix at the start if you want, but it's really not necessary. If they were my plants I would probably mix a "little" Controlled Release Fertilizer (like MG Shake and Feed, which has all the nutrients,) to the mix at the beginning. Then, once the plants get establisked, I would give gentle weekly feedings of water soluble ammonium sulfate 21-0-0. Again, I suggest reading up on blueberry fertilization until you feel more comfortable with it. I can definitely relate to it being overwhelming at the beginning, but you will figure it out eventually. Your mix sounds good, now all you have to do is figure out the fertilizer part. It wouldn't hurt to just pot them up now, and add the fertilizer a little later. Where are you located? No fertilizer after August because the plants need to begin to go dormant rather than force new growth.

Even if there was a a significant N supply, there wouldn't be a notable breakdown of the bark within such a short period. Might you be noting the bark particles snuggling together more tightly, which reduces the o/a volume by diminishing air space? How long a soil lasts can be over-shadowed by the need to repot or divide plantings, or in some cases just turn them onto the compost pile if the planting is comprised of annuals. As plantings mature, the root system often become a part of the soil structure (with some soils, that never happens because the lower part of the soil is always saturated). I've seen some plantings where at least 90% of the original soil mass has gassed off, leaving only a small fraction of soil in a pot filled with roots. If you are growing a plant that doesn't produce an extensive root system, you can probably go 2 years using the 5:1:1 mix before collapse becomes much of a problem. If you have a planting with a vigorous root system, once you get to the 2 or 3 year point, the roots have either becoming a part of the soil's structure, so even as the 5:1:1 soil breaks down and collapses, the roots themselves should be contributing to aeration and drainage, or roots have formed a mat so dense that water and gases don't penetrate. In either case the remedy is repotting or if appropriate, dividing. Al