Note: due to the various micro-climates on our West Coast, these are approximate times to plant. Experiment to find what works for you.
Oats: as early as you can get onto the soil in the New Year, or "whenever the mud dries enough in the spring to be workable," as Gene Logsdon says. Possibly late February, depending on your micro-climate and soil.
Spring-planted rye: early March.
Quinoa: April. Don't try to overwinter quinoa, since it doesn't like being wet.
Spring Wheats: April.
Kamut (Polish wheat): April.
Winter Wheats: September/October.
Fall-planted Rye: October.
Just like grass seed. You can sprinkle it, "broadcast" it in sweeping arcs, plant by hand in tidy rows, or use a row seeder. We prefer to plant in rows: it makes it easier to weed.
Try to ensure even spacing of about 1 inch between seeds (the plants will fill in the gaps with "tillers" that they send out, stifling weed growth and producing a greater yield at harvest time).
After planting, cover the seed with a few centimetres of soil or rake the seeds in, then tamp the soil down to ensure good contact between the seed and the soil.
According to the companion planting bible, Carrots Love Tomatoes, chamomile increases wheat yields (plant 1 part chamomile to every 100 parts wheat). Bachelor Buttons (a flower) aids rye production when planted in a 1:100 ratio.
It should be noted that grains grow 3+ feet tall, and often require little water, so don't expect your companion plants to perform their best given this shaded, dry environment.
Winter wheat is a type of wheat that is planted from September to December in the Northern Hemisphere. Winter wheat sprouts before freezing occurs, then becomes dormant until the soil warms in the spring. Winter wheat needs a few weeks of cold before being able to flower; however, persistent snow cover might be disadvantageous. It is ready to be harvested by early July.
Hard winter wheats have a higher gluten protein content than other wheats. They are used to make flour for yeast breads, or are blended with soft spring wheats to make the all-purpose flour used in a wide variety of baked products. Soft wheat is used for specialty or cake flour. Durum, the hardest wheat, is primarily used for making pasta. Almost all durum wheat grown in North America is spring-planted.
In our temperate West Coast climate, many growers are experimenting with planting spring wheat varieties in the winter, to see if they'll survive the rainy/cold season. At Makaria Farm in Duncan we've planted hard white spring wheat in the fall and the spring with great success:
If you plant in the fall, the grain will get a head-start before the chilly winter hits. This may result in a stronger plant and therefore a better yield at harvest time (approx. 20%). You also might be able to harvest a few weeks earlier (e.g. July/August instead of August/September).
IMPORTANT: Note that some cereal grains simply won't survive cold winter temperatures (e.g. oats, quinoa, amaranth), so must be planted in the spring.
Ideally, you should start preparing the soil about six months or more before planting grains. Any sod should be removed or tilled into the top 6 inches of soil. After tilling with a tractor or rototiller, plant peas, beans, fall rye, or another green manure crop to help break up the soil and improve fertility. This crop can be tilled back into the soil once or more. Till once more just before planting your grain seed, to discourage any weeds.
Wire worms are a major pest, especially in newly-tilled pasture: they live the good life in the roots of grass plants, and will head straight for your grain when it's planted. Island farmers have lost entire grain crops to wire worms. One organic (but not guaranteed) solution is nematodes, which can be sprayed onto the soil once the weather is warm enough. Generally speaking, if you have diverse, healthy soil biology then there shouldn't be an overpopulation of any pest, including wire worms.
We (Makaria Farm) planted grain in recently tilled pasture in 2009, and saw little if any wireworm damage in our grain crops. The wireworms may have been distracted by the neighbouring potato fields . . .
Crop rotation is a best practice, no matter what you're growing. It means that you never plant the same crop in subsequent years.