I did a google search and found that Ace Hardware advertises the Pro-Mix potting soil. I did a google search on earthbox planter and found several sites ... even a forum, which has quite a long discussion about different kinds of "soilless mix" to use in this kind of container. That might prove helpful to you. http://forum.earthbox.com/index.php?topic=1623.0 Did your earthbox not come with directions? Not very "user friendly", huh? The Garden Web Container Gardening Forum might also prove helpful. http://forums2.gardenweb.com/forums/contain/ Since cost is a factor ... the free "soil"[?] at the dump sounds tempting. But Mendopete's caution is well-placed. That can be very nasty stuff, no matter how attractive. How does it smell? You may want to test it out in one earth box and other container, just to see how it works out. If good stuff, it will set your timing off a little, but not as much as filling all containers with 'iffy' stuff. It's a gamble ... gamble big or gamble small ... it's your call.

You mentioned getting bagged top soil. Bagged top soil is not dirt — if you read the bag — it will say under top soil “soil conditioner” or something like that. If you read the ingredients you will see bark, peat, compost. Some brands add in a few other things in very small quantities to make you think you are getting something special— you aren’t because it’s in such small amounts compared to the bark, peat, and compost. And that’s providing what they say is in the bag is in the bag. The compost can be anything from municipal waste (including human waste) or it can be trees that have been chopped down or storm downed that could be diseased or full of pests, or it can be yard waste which is what landscapers and homeowners get rid of and includes leaves, branches, grass clippings, etc. The wood components in all mulch with the except of true bark (pine or hardwood) can be anything from trees as mentioned above, to recyled pallets, recyled furniture, discarded house trim, siding, etc when remodeling is done or a house or building (residential or commercial) is torn down — whatever and wherever they find wood. My issues is that the recyled wood can contain lead paint, heavy metals and pesticides, herbicides, paints, all types of chemicals etc stored on pallets for long periods and have leaked. You don’t know until you look at them. Also house and building debris may have all kinds of chemicals, and discarded furniture has varnish, solvents, paints, etc in those. The premise is folks are mulching their lawns and ornamentals with these mulches so should be okay, however, once broken down they end up in “compost” and are mixed in with expensive turf and garden bed mixes in bulk and bagged. No matter what they tell you — there is no one checking the wood or trees etc to see if there are termites, lead paint or paint period or some disease. They do check the line to make sure rocks, concrete, metal, etc doesn’t slip through but that’s because they don’t want to tear up their grinders. But truly once this stuff is broke down, know one knows. But what makes me so darn made is they call it topsoil when they know there is no soil in the bag. Potting soil is pine bark, peat moss, perlite, and sometimes vermiculite along with other good sounding things. Top quality like ProMix — you can go to their website, find the type and search their site for the ingredients. It is usually pine bark (the actual bark of the tree - not the interior wood), peat moss, perlite, and lime to adjust pH plus you can buy some with mycorrhizae and biofungicides already added which is what I get. Good luck. As others mentioned — buy bulk and try to find someone who will mix to your liking and who will give you a soil test or least the pH for the pile in front of you. But sly ones will even take sub/fill dirt, run it thru grinder and screen to make it look fluffy and add in compost (aged or dyed ground wood) so it looks dark and rich when it is mostly crap dirt. In addition, on the cases where they are paying you to take — you better run for the hills and in free too. A friend had about 50-75 yds delivered to his farm to spread in low area so he could get to it a little better each spring. After he planted corn, it was dying and in awful shape, got the extension folks out and it was tested. It was so bad and he was above a creek — full of heavy metals and toxic chemical substances from a remediation project - he got fined and was ordered by the state to have it removed and pay to clean up the creek. He gave them the guy’s name and guess what — no one answered, no one knew him, nothing - it was a big mess and a whole lot of money but as he said - he should have done his due diligence and he was in such a hurry for free and fell for the story. Lucky for my friend, the state or federal whichever worked with him because they had similar situations with others over the same guys. Apparently these guys were paid to take the bad soil to a specified dump site that’s lined and set up to handle such stuff — instead they dumped it on vacant land, put ad in paper for free pickup and then charged to deliver it to you — and disappeared having given false information. And of course, no one thought to ask for identification, or to write down license plates, nothing. The owners of the land didn’t know anything, didn’t even live in the same state, just empty inherited land they hadn’t sold due to prices, weren’t even renting the land, hadn’t seen the property for decades. They were in hot water too — same issue of contaminated soil able to wash to a small river off the edge and already causing issues downstream on someone’s native plantings. Obviously, these scoped the property out and was accessing the back where no one ever saw them. When the authorities went there after someone reported issues but were a pickup not a delivery — they saw where the dirt had been and some still was but no hide nor hair of the guys. It took months to unearth the folks who had gotten caught up in this mess. So be careful - free can be quite costly to the tune of tens and tens of thousands of dollars, fines, time in jail, etc. As someone mentioned — you want native top soil - actual dirt with minerals and organic matter. If buying bagged products, only get from “reputable” companies you can get back to in order to get your money back. Compost and top soil/soil,conditioners and many mulches are not standardized so each load is different. Higher brands of bark only mulch will be as close to what it says as anything but still it will vary because the types of hardwoods vary and there is a big difference between bark mulch, and just mulch. “Mulch” is any and everything wood; pine bark mulch should only be the bark of the pine tree. And hardwood bulk mulch should only be the bark. If it doesn’t say bark...it’s anything, might be hardwood tree but could be any part of the tree and it does make a difference. Also, ask if they have dyed any of their compost or mulch products. They will call it aged and then dye it to make it look like it has aged for a longtime. The longer mulch has aged, and is getting close to dirt consistency, the less it will tie up the nitrogen and some of the other nutrients in your soil while it tries to break down the mulch. This means it draws those nutrients from your plants. I grow orchids, when you grow them in bark, you always have to supplement with more frequent applications of nitrogen — I use a basic 20-20-20 and then supplement around with my other items like calcium, magnesium, trace minerals, etc.

If you need bulk quantities, you might consider the county free mulch sites. Free is good. Not many people are thinking about gardening in December/January so I get 4-5 pickup truck loads then. It is aged, so is mostly broken down into black soil. Now in Feb./Mar., it is fresher, not as aged and more like mulch, because more people are feeling the spring weather and getting some. I don't know what part of St Pete you are in, but there is one a few blocks east of 1st St on 62nd Ave N, across the street from a golf course. Just something to keep in mind for future reference.

sandy loam is 33% sand, 33% top soil, and 33% Mulch. it's much heavier than manure alone, and I got the same volume, yet I got charged more for the manure. They weigh your vehicle when you buy bulk soil at these places. and I'm not trying to find an answer, I'm just sharing my experience so other gardeners here can see the difference in prices from both places. We've had long discussions here in the past on where to get bulk soil mixes from and pioneersand always gets mentioned. I'm just pointing out that there's an alternative and cheaper place to get it from.