All About Growing Sorghum

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Illustration by Keith Ward
Step aside, honey and maple syrup — there’s a new sweetener on the block, and it can be grown and processed right at home. If you haven’t tried sweet sorghum syrup, you’re missing out.

(For details on growing many other vegetables and fruits, visit our Crop at a Glancecollection page.)

One of the most versatile members of the grass family, sorghum (Sorghum bicolor) can be grown for grain, crafting or for processing into sorghum syrup. Appropriate sorghum varieties must be chosen for each use, but all types are as easy to grow as corn.

Sorghum grows best where summers are quite warm, with daytime temperatures regularly topping 90 degrees Fahrenheit. Sandy soils in warm climates are especially good for growing sorghum because it withstands drought and flooding better than corn does.

Types of Sorghum

Understand the three types of sorghum is key to choosing the best varieties to grow.

Grain sorghum, also called milo, produces tall panicles covered with small, round seeds in late summer. The grain can be milled into fresh flour, and some varieties such as ‘Tarahumara’ can be popped like popcorn. Cracked grain sorghum makes excellent animal feed.

Sweet sorghum, also called cane sorghum, is grown for the sweet juice that is extracted from the tall stalks. The ‘Dale’ variety is productive in a range of climates, or you can try heirloom sweet sorghum varieties like ‘Sugar Drip’ or ‘Rox Orange.’ For more information on this type of sorghum, go to Sweet Sorghum Revival: How to Grow Your Own Natural Sweetener.

Broom corn is a type of sorghum that holds its seeds on sturdy straws, perfect for trimming into brooms. The ornamental tops also can be used in dried arrangements. Broom corn varieties vary in the color of the seeds, which may be black, red, orange or white. The seeds are eagerly eaten by chickens and other animals, and are most palatable when cracked.

How to Plant Sorghum

There is no rush to plant sorghum, which needs warm soil to germinate and grow. Even in warm climates, sorghum is customarily planted in late May or early June.

Prepare soil much as you would for corn, and be sure to mix a balanced organic fertilizer into the bed or row before planting. Unlike corn, sorghum is self-fertile, so a large plot is not needed for pollination purposes. Sow seeds one-half inch deep and 4 inches apart, and thin to 8 inches apart when the seedlings are 4 inches tall.

For more specific recommended planting dates for your local climate — and to design your garden beds — try our Vegetable Garden Planner.

Growing Sorghum

Keep weeds under control until developing sorghum plants are big enough to dominate their space. Six weeks after planting, drench sorghum with a high-nitrogen liquid fertilizer to invigorate new growth. Many grain sorghum varieties grow to only 5 feet tall, but sweet sorghum and broom corn plants can top 8 feet.

Harvesting and Storage

Like corn, grains of sorghum go through an immature “milk” stage when a pierced kernel will bleed a milk-like juice. Sweet sorghum is harvested about two weeks after the milk stage by cutting off the canes at ground level, stripping off the leaves, and setting aside the green canes. The ground, pressed canes yield a sweet, light green juice that is then cooked into sorghum syrup. The barely-mature seeds can be fed to animals, or cooked and eaten like other whole grains.

Grain sorghum and broom corn are harvested later, after the seeds are fully mature, with hard glossy seed coats. Harvest grain sorghum by cutting off the seed clusters with a few inches of stalk attached, and dry them in a warm, well-ventilated place for at least a week. Roll the dried seed heads over a hardware cloth screen to free the seeds, and then winnow out plant debris and store your processed harvest in the freezer. 

When the seeds of broom corn are hard and the plants begin to fail, cut stalks as long as you want them for decorating or crafting purposes. Allow the stalks to dry in small bunches.

Propagating Sorghum

In summer, select vigorous plants for seed production, and make sure they receive adequate food and water throughout the season. In fall, during a period of dry weather, select the largest seeds produced by these plants and save them for replanting.

For growing advice for many more garden crops, check out our complete Crops at a Glance Guide.

Contributing editor Barbara Pleasant gardens in southwest Virginia, where she grows vegetables, herbs, fruits, flowers and a few lucky chickens. Contact Barbara by visiting her website or finding her on Google+.