Need Help with Companion Planting in Square Foot Vegetable Garden

[I asked this question on the Garden Web forum also.]
This is my first garden and I have read a lot about intensive planting and square foot gardening and it makes sense (less weeds, less watering, more veggies). I have also read quite a bit on companion planting and it makes sense -- seems to be the first step in preventing pests organically. Anyway, I am looking for some folks with experience with companion planting in an intensively planted garden.
I live in Northern Alabama and my spot slopes gently toward the south and gets full sun all day long. I prepared my garden spot last year in the late summer. The soil is heavily amended with compost (8 to 12 inches!) and organic fertilizers (soybean meal, alfalfa pellets, some blood meal, etc. tilled in as deep as the tiller would go) The soil is looking very good now -- black, soft and crumbly (even saw some earthworms recently).
Part of my problem is that I do not know how all the plants grow or how big they get.
I am mostly concerned about the onions and the carrots as they are good companions to almost everything. If I companion plant onions with carrots, I fear the onions will not get enough light. Square foot spacing for both carrots and onions is 9 per square foot (i.e., 3"). For example, consider the following square foot diagram:
[C] [O] [C] C = Carrot [O] [C] [O] O = Onion [C] [O] [C]
Would the carrot tops shade the onions too much? I'm thinking something like this might work better:
[C] [C] [X].[O] [O] [O] C = Carrot [C] [C] [X].[O] [O] [O] O = Onion [C] [C] [X].[O] [O] [O] X = Empty
I am not using raised beds, but I have 4' wide rows that are pretty long and run east to west. I want to plant two long rows of okra in one wide row with the rows about 2' apart and the plants about 1' apart within the row. I would like to plant something in the area between the rows. Would the okra plants create too much shade for onions or carrots?
Also, can you interplant carrots with bush beans? If so how do you do it? Along the edge of the beans or in amonst them?
Has anyone done these sorts of things before? Or, am I just "off in the weeds"?
Thanks!
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"Part of my problem is that I do not know how all the plants grow or how big they get."
Successful gardening, sq. ft or otherwise, requires several years of practice, so don/t expect to get it 'just right' the 1st time out.
Being new at this; keep it simple. 1st; learn how to grow your plants intensively; then figure out how to plant them as companions.
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Plant a square of carrots next to a square of parsnips. There is no need to get the plants themselves actually touching.
Works for me. YMMV
Carrots and radish get planted in three rows with beans in the centre row. The radish get pulled as soon as possible, the carrots a little later with the beans last.
again, works for me YMMV
One companion I like is Marigold/Calendula planted as a border round everywhere, get lots of pollinating insects on the plot.
Also grow nasturtium trailing everywhere.
Best advice is 'suck it and see'. Try it your way, you may get fantastic results.
HTH
Dave
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Thanks to everyone for your advice. I going to try to companion plant and will just see how it goes. I've got to put the plants somewhere -- might as well try to arrange them so that they are close to what they like. I'm sure I'll learn alot this first year. If it turns out good, I will expand my garden in the fall.
Thanks again!
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look, onion tops are taller than carrots, and they don't shade things very well. if anything, you need to worry about the onions shading the carrots. second, the carrots are also fairly shade tolerant, so why not deploy the carrots elsewhere, like at the base of tomatoes. finally, onions like nitrogen, but carrots hate it, so no way you can get both large onions and smooth carrots. Companionship or not, you never interplant crops with very different nutrient requirements.
I usually plant lettuce amongst the onions, with the lettuce holding up longer than normal, up to mid-july, because of the partial shading by the onions. The lettuce keeps weeds down (always a problem with onions or garlic).This year I might interplant beets instead. when the onions go in mid-august, I plant bokchoi seedlings in there right away. All three crops like wood ash and nitrogen, and of course the soil is very rich in organic matter.
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