Planting
After reading this article and a few books, you will probably be planting tomatoes of some kind, as well as pole beans, herbs, and a bunch of other veggies. Here again, planning is the key to planting. First, divide the seed packets into slow growing and fast growing, sun needing and shade-okay. This is because you don't want fast growing veggies to be overshadowing slow growers. But even within types of vegetables there are interesting facts. Bibb lettuce tastes better when it's grown next to spinach. Keep the beans away from the onions, the tomatoes away from the cabbage, the cabbage away from the strawberries. This is obviously a planning issue.
In addition, some plants, such as collard greens and African marigold, repel insects.
Oh, yeah, snails and slugs. Okay, I'm just going to tell you. Some guy in my corner of the world buried a jar up to its neck and filled it with beer. The idea was that the snails and slugs are wildly attracted to beer, crawl into the jar, and are drowned. My friend's result was his drunk dog throwing up drowned slugs on the living room rug. Eeeeew. I'm afraid that if I try that technique, I'll come out in the morning and find snails hanging out around the jar with a tiny HDTV watching hoops.
I'm thinking coffee grounds. Salt? No. That affects the soil. Copper? At these prices?
Spacing
Spacing will obviously be influenced not only by the compatibility issue, but also by the position of the bed. Seed spacing can vary. Some will insist that the spacing be closer because of the ability of the soil to support more plants, and others will say that because the plants will be lusher, the packet-listed spacing is good.
It's difficult to give a rule of thumb for plant placement in a biodynamic/ French intensive bed. Actually, the spacing recommended on seed packets will often work out fine, since the heartier "method" —grown adult plants tend to spread farther than do their conventionally raised cousins. It's best to simply estimate the diameter of the adult vegetable's "leaf ball" and use that figure to mark the distance between your plants.
Intercropping, Wide Row, and Succession planting
Intercropping is the idea of planting a quick-growing crop between or inside rows of slower maturing crops so you can use the space more efficiently. Onions and lettuce grow fast, so they can grow best around broccoli, cabbage or tomatoes, which grow slower. An extension of this is succession planting, which is basically crop rotation, i.e. putting in new plants while the other plants are maturing. In wide row, or grid planting, plants are put in groupings or rows a couple of feet wide. This is better for single crop beds, in that watering is easier, and weeds tend not to grow as well.