In our previous post, we set out the basics of where to plant what in your vegetable garden The main issues, as you would expect, are what you want to eat, how much space and light the plants need, and when they should be planted.
But as you work with your garden from year to year, you will integrate many other ideas about where and when to plant things, without even realizing it. You may start to work more effectively with the principles of companion planting - the idea that some plants seem to support the growth and health of some other plants, while still others may actually inhibit growth.
For instance, common wisdom is that peas don't like onions, garlic and other alliums, so don't plant them side-by-side. I don't know for sure that this is true, but still, I tend to keep the two kinds of plants separated. Likewise, as we've probably mentioned elsewhere, tomatoes, parsley and basil tend to like to grow together.
You can also consider planting for pest control: many of the herbs are thought to help repel garden pests, and so they can be useful scattered throughout a garden to lend overall pest resistance. There are certainly various flowers for pest control that we routinely plant in our vegetable gardens: for instance, in one of our clients' raspberry beds, there's a terrible earwig problem, so we'll be planting lots of allysum to try to reduce the problem. (Actually, common wisdom suggests that allysum is a good plant against various surface- and soil-based pests). Likewise, we plant nasturtiums (left), marigolds, geraniums and calendula, for similar reasons.
You can also plant flowers to draw pollinators - especially the really fragrant flowers such as sweet peas (our favourite!), or the kinds of flowers often used to draw hummingbirds.
You may also make planting decisions based on soil conditions: most berry crops tend to prefer a somewhat or fairly acid soil (especially blueberries), so don't plant them next to your chard patch (which really needs a neutral soil to thrive). Potatoes also like a somewhat acid soil, and shouldn't be planted in a bed that's just been limed - and they also do better in a soil with a fair bit of sand, which loosens soil texture and makes it easier for the potatoes themselves to develop.
Similarly, to prevent your broccoli from growing hollow stems, you need less nitrogen in the soil than many other crops prefer - so plant them in an area that hasn't just had a big load of compost added. And since garlic really doesn't like manure - which promotes garlic rust - it should be planted in a soil that's been fertilized with garden compost instead.
Soil depth is also relevant: most vegetables do fine with about 9 inches of soil, but of course postatoes need to be in much deeper beds - about 18 inches. The larger carrot varieties, parsnips and asparagus also need deep soil.
Finally, I also make a lot of planting decisions for aesthetic reasons: the curly kale just looks so great against the deep red cabbage, or the delicate carrot fronds against the pale green of golden marjoram. In the photo above, a broccoli plant is surrounded by young arugula.
Planting is a creative activity - so rather than fretting over it, enjoy the opportunity!