Oh, and another question - I used a scant teaspoon of sodium hexametaphosphate (calgon water softener) in my jar test. Do I need to dispose of the dirt now or can I put it in my compost? My guess is that it's just adding phosphates and won't be too bad to the compost, but I can't find out anything about it's half-life or effect on the environment. I'd rather not lose all that dirt, I value my dirt greatly.

I would get another test done. I am sure there was an error.

The Mason jar test is to evaluate soil texture - like real garden soil. Since there is no 'soil' used in Mel's mix, that test is not relevant - peat moss, compost and vermiculite are not 'soil' and so the test results from this method are really quite meaningless. And yes, compost, especially bagged compost could very well have some sand in it.

If you are concerned about nutrient content in your raised beds, get a proper soil test done. And you should be aware that vermiculite is not a great product to use for much of anything other than seed starting. It absorbs many times its weight in water and once fully saturated, collapses and no longer offers any drainage enhancement or porosity to the soil mix. In fact, it creates just the opposite conditions, which could be contributing to your poor performance.

btw, most raised bed soil mixes (excluding Mel's mix) include real "garden soil". This is because garden soil is mineral based and those minerals are just as necessary for good plant health as are the more usually added N,P &K. Unless you are also fertilizing with something that provides trace elements (those soil minerals), your plants may be exhibiting deficiencies that can affect growth and production.

"The Mason jar test is to evaluate soil texture - like real garden soil. Since there is no 'soil' used in Mel's mix, that test is not relevant - peat moss, compost and vermiculite are not 'soil' and so the test results from this method are really quite meaningless. And yes, compost, especially bagged compost could very well have some sand in it."

But it should be high in organic material considering 30% is Peat moss and 30% is compost. That would be 60% organic right? I think Peat would report as organic wouldnt it. I do agree sand is defiantly in store bought compost. Especially Black Cow. I added a layer of black cow one year and a month later, there was just a layer of sand on top of my soil after the manure worked its way in.

Organic matter changes over time.........it continues to decompose. So it could affect the jar test readings. But a soil-less mix is not what that test is intended for nor is it providing you with information that will help determine what's up with your current situation. For that you need a proper soil test that evaluates nutrient content.

Ah, ok, thanks - I'll just rely on the official lab soil test results. And I have been thinking it needs some real soil, so I'll see about getting some living soil, too.

Thanks for your help.

Also, have you been adding fresh compost between plantings? Remember that you should add a few new scoops of compost every time you pull something up. I typically add a half wheel barrow full of compost to each box each year.

BTW I wouldnt add real soil to a raised bed. It will cause compaction. Peat needs replaced around every third year as well.

Actually, it does not :-) A raised bed is not a container........they tend to be well draining just by virtue of the fact of they're being elevated. The vermiculite in the Mel's mix is far more likely to cause compaction than garden soil!!

If you really want to understand how a "proper" soil mix can affect plant performance, you might want to visit the Soils, Mulch and Compost forum.

btw, have you tested you pH recently? That high a proportion of peat could be impacting pH and causing problems as well.

Garden Gal, I guess we will have to disagree. First off we are posting in a square foot gardening forum, so the plans are laid out very clearly in the book "Square Foot Gardening". Mel's mix is soil-less (basis of sfg ) and commercial raised bed mixes are also soil-less. Why do you think this is? Vermiculite also does not compact if you are using garden grade. This is why it is used commercially as well. You can also find just as many people claiming soil in a raised bed/container often becomes compacted. A raised garden is just a larger container. In fact in SFG, Mel even suggests having bottoms on the boxes. This is just a giant container. Here is some good info on Soiless vs soil for raised gardens. click here for a ton of info from folks here on gardenweb Mel's Mix I guess to each their own, but if we are discussing SFG, then the rules are in writing already. Mel states to put a trowel of compost with every new planting. Ive been doing it with great results.

Really, if you squeeze it between you fingers it compacts? What happens when you squeeze anything including garden soil between your fingers? I am sure you teach classes somewhere, and I am sure you understand soil, soil structure all that, as do I. BUT, soil compacts. You can sift top soil and mix with compost, but true soil will compact. And a raised garden is very much like a container. Most of the times the roots will never go into the native soil because they prefer the mix. This is stated multiple times in your Soil forum.

planterjeff, native soil in contact with the ground becomes aerated (with time!) due to decomposition of plant roots and movement of worms and bugs through the soil; if this structure is frequently disturbed by tilling/turning/digging, aeration may not be as good since the insects/worms won't establish and old roots can't break down and the ground will stay compacted. No-till gardening is pretty awesome.

I am interested in your comment on the roots not going into the native soil. Perhaps that is mostly true for very heavy, dense clay soils? Have you experienced this? I have clay-like soil in my yard but this is my first year with SFG so I don't know what will happen as far as root development.

typically if you are doing raised gardens it's because your soil has issues. I live in downtown Atlanta. Our native soil is old compressed red clay, concrete, bricks, glass and probably pretty toxic based on pollution over the years. When I pull my plants at the end of the year, it is rare that I ever have roots reach beyond the mix. Reason being, the mix is where all the nutrients are. Again, my comments are based on this forum. This is square foot gardening. The whole idea is about being able to have a garden in an area where you typically couldn't and then the whole maximizing space thing. Mel's claim is that you only need 6 inches of mels mix to produce an amazing garden. He runs a non profit that focuses on this in third world countries where as the soil would not typically allow for such a garden. I understand soil structure and non til, but those are not conversations for this style. If you just want a garden in the ground then save your money and dont build up. My old garden at my old country house was in ground. No reason for boxes. Bottom line, the idea of this is to grown in an extremely friable, no step, garden with only 6 inches of soil. Its very low maintenance, and requires no fertilizer or tilling because of the structure of mel's mix. Worms and insects make their way into the garden regardless of whether or not it touches the ground. You cannot plant a garden directly into the earth where I live though. They used to use agent orange to clear land in the 60's down here. That's why the EPA is in charge of clearing the belt line around Atlanta. The ground is extremely toxic.

Boy, somebody sure drank the Kool Aid!!

If you like SFG and using Mel's mix - go for it. But don't assign it any mystical or physical properties it doesn't have!! The mix is NOT soil, doesn't have the physical properties of soil so doing a soil texture test on it is a waste of time and will produce meaningless results.

btw, folks garden in raised beds for all sorts of reasons, not simply because their inground soil is difficult to work or they deem it not suitable for growing. And many use soil mixes other than Mel's - most with real soil as a major component - and with excellent results. SFG is not the be-all and end-all you make it out to be.

And I'm sure if you were to look closely you would see all sorts of inground gardens in the Atlanta area.

planterjeff - yikes, your soil sounds really bad. My main reasons for doing a square foot garden (totally separate from Mel Bartholomew's SFG book) are ease of child- and rabbit-proofing, keeping veggies up and away from lawn for convenience with yard work, and forced creativity. Limited space makes me work smarter to get what I want from the land and it feels simpler to make things visually appealing. That matters to me because most of my neighbors don't garden and if I make it more conventionally attractive it's easier to get them on board, or at least not totally against food gardening and edible landscaping.

@danielle yeah, they are pretty and easier to maintain in my opinion as well. My parents actually took to adding raised gardens where their old in ground garden was. It's funny because the old timers all kinda got a ruse out of it. I guess it can be too costly for some though. You know, the cedar and soil mix. Heck one box can cost you $100 bucks to make and fill if you don't have the mixes on your own. But yeah, I think it is worth it. I have mine set between an ally way, really the only place I get sun so I am limited to 40 square feet. With that said, I get a great harvest using this technique. So yeah, you are right, it is versatile.

@gardengal: As I stated, you can use finely sifted top soil and compost as another common mix. I was honestly pointing out that adding shovel fulls of native soil, as the OP asked, is not the solution to his problem. It will/could cause compaction. It most certainly would in my situation. Adding new compost each time he plants will rectify his issue. Also, the soil test would show organic material if it was present. (just pointing out, doesn't matter where the soil/mix came from, the results would be the same regardless of whether or not the OP needed the test. My point about SFG is that the question was asked in SFG forum, not a soil forum, so I would assume the poster is trying to follow SFG, hence I will answer accordingly. Also, just out of curiosity, what Ag dept are you working at?