Growing plants to harvest and use as grains is as easy as growing any flower or vegetable. Here are a few to consider:
Usually thought of as a vegetable, corn is actually a grain. You can grow dry corn the same as you would sweet, but allow it to dry thoroughly on the cob before harvesting the kernels to grind.
Be sure to take preventative measures if you are also growing sweet corn nearby, as their pollen is carried on the wind and there can be cross pollination.
Choose a variety that is meant to use for this purpose, they are less sugary and will dry more easily. One of the best varieties for making your own corn meal is Cherokee White Eagle.
Grind, store and use the way you would store bought cornmeal.
Technically a vegetable, quinoa is a relative of spinach that is fast gaining popularity in restaurants as well as home kitchens. Part of the reason is that quinoa carries a protein not normally found in a vegetable. Especially for vegetarians, this is a wonderful thing.
What you harvest here are the seeds as well, dry, store and use like you would rice. You can also grind the seeds to use like flour.
A beautiful delicate flower that is also grown for its use as a fiber, the seeds of flax are actually wonderfully nutritious. They are a good source of omega-3’s and high in fiber. The milled seeds can be added to many baked goods and can be used as a substitute for eggs.
Often listed under herbs, and sometimes under flowers, Amaranth is a beautiful tall edible whose flower seeds can be used as a grain. In some varieties you can also eat the leaves as a vegetable, bonus! Two of the most common varieties grown for the edible seeds are Love Lies Bleeding and Golden Giant, shown above.
One definition of grains is that they are grasses that produce small edible seeds. Millet fits this description well. Its seeds can be ground for flours or gruel, and it is often also used as bird seed.
One of the most common varieties used in the U.S. is Proso White.
Generally speaking these crops grow quite tall, and the harvest you get for the space may not compare to vegetables you plant instead. Some of these can easily be added to flower beds though, making that space more productive for your food needs.