There really isn't any wiggle room to make mistakes with self-watering containers. You must get a soilless mix with excellent 'wicking' or capillary action. You know you have the right thing if it costs a fortune and it is very light to pick up compared to cheap bags that have soil. I would call around to nursery supply stores and find bales of Pro-mix BX. It is compressed and does, if I remember correctly, 3 to 3 1/2 boxes so you would need 2 bales. It is expensive but the mix can be reused over and over again according to EB and other EB afficionados--just cut off plant, remove leftover fertilizer strip, top off with new potting mix, add new dolomite and fert. I have always started with fresh mix every year but told this is not necessary. When reusing, if the mix in the box is too wet something is blocking drain and you do have to start over and dump that mix, add new to it and then repack. Or in Florida Home Depot has the brand Lamberts Potting Mix --get the largest bag--something like 75 to 85 quarts. One bag does one earthbox with some leftover. Around $14. Ignore any directions that say to add the mix in dry. Much better to moisten it first in a wheel barrel or the bag and don't forget to pack the 2 corners or you will get no wicking. Finally you said you didn't have any success before--did you add the dolomite (calcium and magnesium)? NOT HYDRATED LIME though some EB directions are outdated and still make it out that the two are interchangeable. Espoma makes Garden Lime and is available at HD and Lowes I believe. Bigger bags of dolomite are available much much cheaper but you have to locate them which isn't easy as places will try to sell you the hydrated lime. Fertlizer should be granular with the numbers 5 or higher but not over 15. (2 cups synthetic, 3 cups organic). They work fantastic, that is why you see so many home-made knockoffs being made based on the design features of the earthbox. Plus people want a larger Earthbox so they make their own (I have done it myself). Earthbox people have had requests to make a larger one but said the shipping of a large box would be prohibitively expensive. Good luck.

Hi Laura: As Jacqueline, Tessie, and JeriJen often said: "location, location ...." Tapla's recipe of 5 parts fine mulch, 1 part peat moss, 1 part perlite is best for climate like mine: low-sun, flash flood warning and fast drainage is a must. It is recommended by Douglas Green, an owner of a large Ontario nursery of many plants in pots, including roses. If I use Al's 5-1-1, there is no need to put loose gravels or bark nuggets at the bottom for fast drainage. However, I use super-slow draining MiracleGro in green bag, and medium-slow draining Organic MiracleGro. I skipped this important process of putting loose stuff at the bottom, and regret it terribly. Now I have to dump the soil out of each pot, and start all over. I realize this after a heavy-rain simulation with a hose, with the pot flooding over and loses 1" of soil - which happens every time it rains here! Sure, Field Roebuck said it's not important, just put a paper towel at the bottom of the pot, and fill up with soil. His Texas climate doesn't have the low-sun, and 6" of rain flash flood. Each region should have its own recipe of best potting soil. Now I realize that the regular MiracleGro potting soil (green bag) might have been made for indoor pots, where one puts 1 measly cup of water per week. It's not meant for several outdoor heavy thunderstorms with 4 to 6" of rain per bout like my climate.

Aha, finally a question I can answer! (I'm new here but I've read just about every post on potting mix I could find.) Head on over to the "Container" forum and read the series of posts about this very topic from a very knowledgeable poster named Al/Tapla and the many many many other people who have had success with his potting mixes. There are also other folks who use different mixes, but there's definitely concensus about the idea of creating a fast draining but well aerated mix for containers to grow successfully long term. The key thing I've learned about potted citrus is they don't like soggy roots. Basic potting mixes have too much organic material and that not only stays wet too long, but it breaks down and collapses quickly, accelerating root rot and the poor nutrient uptake. When I got here a couple weeks ago, the idea of "home brewing" my own potting mix sounded so revolutionary and a bit crazy, and now, I'm a convert. I do a slight variation of the mix Al recommends, because I want to grow using a bit more organic material than he uses. You might also want to read his fertilizer posts... all very helpful. Good luck with your citrus! Here is a link that might be useful: Al's Container Potting Mix Post

Yep one thing I learned at the end of some growing seasons, was that the plant I thought would fill up the pot with roots just barely had a small rootball, not worth putting it in such a large pot. So as Nick said, knowing that may help you save some soil. This is why some pots with various plants in arrangement look so great, because you would think the roots are all competing with each other, but in fact, they are growing at different depths or different areas of the pot, not really growing into the entire pot. I have used the techniques of putting stuff into the large pots, or even growing smaller pots in a larger pot, and you can replace the smaller pot with any plant in a similar pot whenever you want. I really recommend that method if soil quantity is a concern. At the same time, you have the beginnings of a good soil mix. The leaves may not be at the right stage for being about 1/3 of your potting mix, but you can also get some bags of compost and mix it with what you have. If the leaves have composted to the fine dirt look, it's good, but if it is still in some rotting stage, it might not be. There are also more topics on what kind of pot soil is good, but you can learn more on that as you go.