did you mean to post this in the Square Foot Garden forum?

A (raised?) bed is just gardening at altitude - very low altitude and the physics of water movement that apply in your garden also apply to a raised bed. There is no reason you can't use the sandy mix. My raised beds have a good amount of fine sand in them.
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The soil is comprised of approx
5 parts partially composted pine bark
2 parts sphagnum peat (could also use 1 additional part Michigan or reed/sedge peat)
1-2 parts Turface
1-2 parts builders sand
dolomitic lime
but I could easily have used more sand in this soil.

If the volume of the bed is 66 cu ft, and you're adding 6 - 2 cu ft bags of sand to 66 cu ft of soil, and the bags each contain 25% sand, it calculates that the presence of the sand in the bags only accounts for 3.8% of the total volume - you could easily afford to add a few bags of Turface, or even more sand, to keep the soil 'bulked up' (reduce shrinkage). If it's the Black Kow that is 66 cu ft, how are we to guess at the size of the bed? What's in Black Kow?

If your concern was for aeration - don't worry about it. The physics of growing in a container is quite different than growing in the ground.

I can't help any more, based on the info given, but I tried, ;o)

JAG - I intended on posting in this particular forum, because of the various mixes that people use in their containers. I didn't feel that the soil forum would have been adequate, because it is mainly comprised of discussions on composting. I don't recall ever seeing a discussion about sand. Plus, this is where you and Al are - the walking, talking encyclopedias of everything. :-)

Al - Yes, it is a raised bed. My concern is drainage, compaction, aeration, stuff like that. I just didn't want to ruin the quality of the bed by adding the sandy stuff to it. BTW, the overall quantity of combined ingredients is 66 cu. ft., sorry for the misconception.

EG

It sounds great to me. We just got a Lowes here and I must remember to check it out. Al

Ok then, EG - did you get your questions answered to your satisfaction? ;o)

BTW - I have to look everything up - JaG just knows it. ;o)

Al

BTW - I have to look everything up - JaG just knows it. ;o)

Oh please. You look it up and I make it up ;)

On the topic of sand, I agree with Al that there just isn't going to be enough of it to have any major impact. Have you grown a full year in the bed yet? The reason I ask is that I started with Mel's mix in my beds and while I liked it, I added things to it over the years. The compost 'goes away' pretty quickly so I started adding more stable materials to it.

My advice is to amend gradually and see how you like the mix both in the wet season as well as the dry part. It's already a raised bed, will already offer good to great drainage and you don't really want to end up with an intensely planted bed that you have to rush home to water before everything wilts.

Also, stuff like peat and bark become hydrophobic when too dry and aren't the easiest to rewet in a raised bed setting without a soaker hose or a lot of patience. Rain=good :)

tapla - yeah, I got the answers I was looking for. I believe these 6 bags will be ok for this amendment, but only homemade compost after that. Thanks!

JAG - I have grown 2 crops in the bed already, and they did fantastic. I manually water from watering cans, and use saved rainwater. It's watered every 3 days until July, then every 2 days thereafter. I agree, the top layer of the bed gets pretty dried out between waterings, but still performs quite well. Thanks for all of the input. I feel better now!

See? I knew this was the right forum! :-)

EG

Here is a link that might be useful: Check out my gardening Blog

Lol - I hope no one remembers that remark - I really don't often look anything up - as I'm sure you don't either. ;o)

Raised beds offer you a TON of leeway insofar as what will work as a soil in them. You could easily use 3'4 sand and 1/4 organic component & have great results. If you consider that most garden soils are >95% mineral with Some things to consider:

With the mix I started with (above), as noted above, it was a little difficult to rewet for the first year. The surface often became hydrophobic to the degree that I had to water the surface & then come back a few minutes later and water again. The second watering was then readily absorbed. If I was making the soil again, I would add a greater % of mineral - either in the form of sand, Turface, crushed granite, or native topsoil. The reason for that is soil stability/shrinkage reduction. Raised bed soils with a high % of organic components shrink rapidly. I'm fixing that as I go by recycling all my used gritty mix (a considerable amount) by turning it back into the raised beds, thus increasing the mineral content (as the organics break down).

The last thing I'll mention is to watch for N immobilization - especially/mainly for the first year. Whether your wont is to use organic or chemical fertilizers, there's a good chance you'll need a little heavier hand on the N supply.

Al

Al - that was very informative! Thanks for taking the time to help me. It is greatly appreciated. I will definitely add the bags of sand/bark/manure/needle fines with a feeling of confidence now.

EG

I meant to add something after I said, "You could easily use 3/4 sand and 1/4 organic component & have great results." I should have added "if you are willing to water a little more often." Fine pumice or some Turface, something with some internal porosity and shaped more irregularly mixed into your soil, instead of a high % of sand would be a very good choice.

Ah - never mind. I'm just thinking back to your OP, and the vermiculite will fill that need in a raised bed. Sorry. ;o)

Al