You're welcome. Thanks again, for being so kind. Some thoughts I offered in another, older threads on this forum. They should pretty much answer your question, and may even be quoted in the text somewhere up this thread (if so, I apologize for the redundancy): In my estimation, the only case to be made for reusing container soils is one of economics, and you'll never find me argue against making that decision. If you can't afford, you can't afford it. That said and setting economics aside, you might decide to reuse soil for reasons other than economical. Perhaps the effort involved with acquiring (or making your own) soil is something you might not wish to go through or be bothered with. In any case, it would be difficult to show that soils in a more advanced state of structural collapse can somehow be preferred to a soil that can be counted on to maintain its structure for the entire growth cycle. So, if the economic aspect is set aside, at some point you must decide that "my used soil is good enough" and that you're willing to accept whatever the results of that decision are. All soils are not created equal. The soils I grow in are usually pine bark based & collapse structurally at a much slower rate that peat based soils, yet I usually choose to turn them into the garden or give them over to a compost pile where they serve a better purpose than as a container soil after a year of service. Some plantings (like woody materials and some perennials) do pretty well the second year in the same bark-based soil, and with careful watering, I'm usually able to get them through a third year w/o root issues. Watering habits are an extremely important part of container gardening. Well structured soils that drain well are much more forgiving and certainly favor success on the part of the more inexperienced gardeners. As soils age, water retention increases and growing becomes increasingly difficult. If your (anyone's) excellence in watering skills allows you to grow in an aging medium, or if your decision that "good enough" is good enough for you, then it's (your decision) is good enough for me, too. The phrases "it works for me" or "I've done it this way for years w/o problems" is often offered up as good reason to continue the status quo, but there's not much substance there. I'm being called away now, but I'll leave with something I offered in reply on a recent thread: "... First, plants really aren't particular about what soil is made of. As long as you're willing to stand over your plant & water every 10 minutes, you can grow most plants perfectly well in a bucket of marbles. Mix a little of the proper fertilizers in the water & you're good to go. The plant has all it needs - water, nutrients, air in the root zone, and something to hold it in place. So, if we can grow in marbles, how can a soil fail? Our growing skills fail us more often than our soils fail. We often lack the experience or knowledge to recognize the shortcomings of our soils and to adjust for them. The lower our experience/knowledge levels are, the more nearly perfect should be the soils we grow in, but this is a catch 22 situation because hidden in the inexperience is the inability to even recognize differences between good and bad soil(s). Container soils fail when their structure fails. When we select soils with components that break down quickly or that are so small they find their way into and clog macro-pores, we begin our growing attempts under a handicap. I see anecdotes about reusing soils, even recommendations to do it all over these forums. I don't argue with the practice, but I (very) rarely do it, even when growing flowery annuals, meant only for a single season. Soils don't break down at an even rate. If you assign a soil a life of two years and imagine that the soil goes from perfect to unusable in that time, it's likely it would be fine for the first year, lose about 25% of its suitability in the first half of the second year, and lose the other 75% in the last half of the second year. This is an approximation & is only meant to illustrate the exponential rate at which soils collapse. Soils that are suitable for only a growing season show a similar rate of decline, but at an accelerated rate. When a used soil is mixed with fresh soil after a growing season, the old soil particles are in or about to begin a period of accelerated decay. I choose to turn them into the garden or they find their way to a compost pile. Unless the reasons are economical, I find it difficult to imagine why anyone would add garden soils to container soils. It destroys aeration and usually causes soils to retain too much water for too long. Sand (unless approaching the size of BB's), has the same effect. I don't use compost in soils because of the negative effect on aeration/drainage. The small amount of micro-nutrients provided by compost can be more efficiently added, organically or inorganically, via other vehicles. To boil this all down, a container soil fails when the inverse relationship between aeration/drainage goes awry. When aeration is reduced, soggy soil is the result, and trouble is in the making. I've mentioned before that I don't post here to get people to convert to a particular mix or blend of soil. I post what I know will work very well for anyone who can get appropriate ingredients & modify the mix to suit their climate & other cultural conditions. If you use a mix that guarantees good aeration for the expected life of the planting - you're in good shape. Most peat based mixes will not work well in extended life plantings. Conifer bark based mixes, on the other hand, retain structure for much longer periods. If you still have questions, please don't hesitate .... Al

buy calcium nitrate from the same people you get the soluble hydro from or from a landscape supply company. I think it runs about $50 for a 50lb bag. your TDS sounds about right with what I typically run.(620ppm) you don't need to change it weekly. you're dumping to much fertilizer into to ground that way. When the water runs low, check the EC and add water or concentrated solution to bring it back to normal or a balanced solution if it is normal. only change it every two weeks to one month. You can actually run it that way longer if you wish, but then you may start to see more effects from an imbalanced nutrient solution. (I've run them 2+ months that way) To be truly environmentally friendly you collect your "leftover"'s after each change out in a larger container. After you've accumulated enough (say 10 changes) you have that bulk mixture tested and balance it back to what you need. But for a home grower that is probably a bit much.

Agree with the above. I add compost, dehydrated chicken manure and lime (if needed). Also, urea might be a good additive to add nitrogen to your soil. A good idea is to get your soil tested or measure the pH with a pH meter because nutrients cannot be accessed by the plant unless the pH is at an optimum level. Throughout the growing season, I add fish emulsion, too.

Linked a number of previous discussions about this below. As you will see there are several different approchaes folks use. As I have posted in some of those discussions I dump all my containers out onto a large tarp and spread it out to dry well in the sun - that alone takes care of some of the resident bacteria. Then remove all the root clumps and other debris, mix in approx. 1/3 new quality container mix with it and also add a good dose of Osmocote or other slow release fertilizer and refill the containers. dave Here is a link that might be useful: Reusing container soil discussions