Many gardeners may not have heard of the sorghum plant, though it is one of the most common and useful cereal crops! It is believed that the plant was first domesticated in the Niger River Valley of West Africa and then became an important crop for cultures all over Africa, the Middle East, and South Asia.
Sorghum originated as an ancient grain, but is now commercially grown for many different purposes, including livestock feed, sorghum syrup, weaving material, and floral arrangements. It can also be used in industrial processes like ethanol production.
Sorghum is not commonly grown in many backyard gardens in spite of its popularity in other countries and its multiple uses. Sorghum is a viable option for many home gardeners, especially if they already have experience growing other whole grains.
All About Sorghum
Sorghum bicolor is a cereal crop that is commonly known as sorghum, great millet, broom corn, guinea corn, milo, among many others. It is one of the world’s top five cereal crops. Sorghum first originated in West Africa, but has since spread to other parts of Africa, the Middle East, and even other parts of the world. It is known as a nutritional crop due to its many health benefits.
Sorghum grows in a similar way to other grain crops, with large stalks that end in a seed head. Sorghum plants look a lot like corn plants, but the seeds grow in a cluster at the top of the plant instead of in an ear like corn.
Sorghum is a crop that is widely used by farmers as a main ingredient in food for livestock. The grain from this crop is higher in nutrients and protein than many other crops, and can be used for animal feed as either hay or silage. After the sorghum seeds have been harvested, the leftover stalks can be turned into a pulp, which can be used to make wallboard and other construction materials. Broom sorghum, also known as broomcorn, is a variety of sorghum that is grown to create traditional style brooms. One more recent application for sorghum is in the production of ethanol. Sweet sorghum is a type of grass that is harvested for making syrup. The syrup is then fermented and turned into ethanol, which is a type of alcohol.
There are many types and varieties of sorghums. The main types of plants used to make silage are forage sorghums, grain sorghums (milo), and sorghum-sudan hybrids. The sorghum-sudan crosses and pearl millet are not as good for silage as they are for grazing or green chop. Silage is most commonly made from forage sorghum because it produces more biomass than grain sorghum. Although forage sorghums can grow to be as tall as corn, they typically yield less total digestible nutrients per acre, resulting in lower milk production per acre. When harvested for silage, forage sorghums will produce higher yields than other sorghum types, containing 20%–25% grain, as opposed to up to 60% grain found in corn silage. Grain sorghums grow to a height of 3–5 feet. Grain sorghums will produce half to two-thirds as much silage as forage sorghums. 50% to 60% of grain sorghum yields will be grain, making it only slightly lower in nutritional value than corn silage. Sorghum is often planted on dry land after corn as a summer crop in Florida that is harvested in the fall.
Sorghum can be planted as an alternative to corn if planting is delayed or if conditions are not favorable for corn. One of the things that makes sorghum so great is its ability to thrive in less-than-ideal conditions. Unlike corn, sorghum is able to quickly recover from unfavorable conditions and produce more crop. However, if it’s too cold in the fall, tillering can be extended and interfere with harvesting. Drying down forage sorghum can be a problem.
Planting Date, Population, Row Width, and Depth
Since sorghum is more sensitive to cold temperatures than corn, farmers in north Florida normally wait until after the first of April to plant. This gives the sorghum plants the best chance to survive since there are minimal chances of cold fronts and the soils are warm. You can plant sorghum as early as February in south Florida. You can plant new plants until about 120 days before the growing season is over, or before the first frost. If crops are planted after mid-June, they will not grow as well as crops planted earlier and will be more susceptible to diseases and pests. If you don’t water your spring plants in south Florida, they may die from a lack of water. If you’re looking to grow a crop in dry conditions, sorghum may be a better option than corn. While grain or silage sorghums planted early may produce a second crop, the yields are often significantly lower than the original harvest – especially if the first crop was harvested at full maturity.
Sorghum can either be planted in rows, or broadcast. The recommended number of sorghum plants per acre in Florida ranges from 70,000 to 120,000. If you’re planting in narrow rows and moisture isn’t an issue, you can get away with a higher population. However, having a higher population of plants generally increases the chance of the plants falling over, especially for BMR varieties. This can reduce the production and quality of silage, and make the harvest more difficult. Sorghum can produce a lot of stalks from a single plant, and can still produce a good yield even when planted at lower densities. The target seeding rate for broadcasting is 10-15 lb per acre. The majority of sorghum that is planted on dairy farms is done so in 30-inch rows, which is similar to the way corn is planted. This is done so that the same equipment can be used for both crops. The new forage heads have circular cutters that allow crops to be harvested in wide rows, no matter how they were planted. The width of the forage chopper head should be matched to the width of the rows being harvested. The depth that seeds should be planted at is 1.5 inches, no matter what seeding method is being used. The soil should be moist when the seeds are planted, and they should be covered.
Seed treatment is very important for sorghum. In most cases, seeds come with a fungicide, insecticide, and seed safener treatment.
There is a lot of variation in the physical characteristics (such as height, tillering, and nutrient content) and traits (such as brown midrib (BMR), brachytic dwarf, and photoperiod sensitivity) of different sorghum hybrids. The desired traits and use will determine the choice of hybrid. Choose a hybrid that won’t regrow much and is tall with sweet stalks for single-cut silage. For grazing or multiple cuts, it is desirable for sorghum x sudan hybrids to have strong tillering and regrowth capacity.
Some key factors that determine which sorghum hybrids are selected for silage are how well they adapt to local conditions, what time of year they are planted (spring or summer), how tolerant they are to disease and insects, and how productive they are. Sorghum is very susceptible to sugarcane aphids which can have a significant impact on both yield and quality. Anthracnose and other leaf blights can have a negative impact on the productivity and quality of silage. Sorghum usually has more soluble sugars than corn does. The higher the concentration of sugars, the more fermentation will occur, and the pH will drop more quickly.
Sorghum grows quickly, and its success depends largely on its preparation. It grows quickly once established and requires minimal maintenance.
Sun and Temperature
Sunlight and warmth are two very important factors in the growth of sorghum. Ideally, you should choose a spot that gets plenty of sun throughout the day during the summer months. The ideal temperature range for growing sorghum is 80-90°F. While sorghum can tolerate light frosts, the plant will die if the main stem is frozen. Sorghum germinates best in warm soil, around 60°F or above. When the temperature of the soil starts to fall below 60 degrees Fahrenheit, the germination of sorghum will become inconsistent.
Water and Humidity
Sorghum grows best in soil that is moist most of the time but not waterlogged. Aim for 3”–4” of water roughly every 10 days. Watering sorghum in the morning helps keep it cooler during the hot hours of the day. Sorghum is a type of grass that can grow in dry or wet conditions, but it produces less grain when it is exposed to extreme conditions of either kind. It is best to water the plants at the base using a soaker hose or drip irrigation to avoid getting the leaves or seed head wet.
The best soil for sorghum is one that drains well and is slightly acidic, with a pH of 5.5-6.5. Sorghum does best in soil that has been amended with compost and a fertilizer that is high in nitrogen. Sorghum doesn’t tolerate competition from weeds well, so take care to avoid having weed seeds in the soil, especially when sorghum is young.
Sorghum is a type of grass that relies on large amounts of nitrogen for quick growth. Fertilizers that are high in nitrogen, like blood meal or feather meal, work well. A nitrogen-heavy fertilizer should be used every 6 weeks throughout the growing season, even with a healthy topping of compost. Soil that is healthy should provide the necessary phosphate and potassium for sorghum growth, though they are not as important as other nutrients.
Except for the time when it is being harvested, sorghum does not need to be pruned or trained in any special way. After harvesting the grain sorghum produces, the plants will occasionally produce a second crop of grain sorghum under the right conditions, but most gardeners prune the stalks back and use them in the compost bin.
Sorghum is propagated only by seed. For information on planting, see the planting section above! Sorghum seeds will grow readily if left on the stalk.
There are three main types of sorghum – sweet sorghum, grain sorghum, and broom sorghum – and the harvesting technique differs depending on which one you are growing. Sweet sorghum is also known as cane sorghum.
Cut the sorghum stalks at the base about two weeks after the “milk” stage if you are growing them to produce syrup. The milk stage is when the corn kernels will produce a milky substance when you press them with your fingernail. Next, remove the leaves from the stalks and press the canes to extract a light green juice. Cook this down into sorghum syrup.
The crop needs to be left until the seeds are fully developed. Once the seeds are mature and have a hard, glossy exterior, they are ready to be harvested. Cut the stalk close to the seed head and leave it to dry for a week in a warm place. After the seed heads are dry, roll them over a section of hardware cloth or wide sieve so the seeds will fall out.
The dried stalks and seed heads of broom sorghum can be cut and used to make traditional brooms, floral arrangements, or other crafts.
You can either eat processed, dry grain sorghum right away or keep it in a cool, dark place in a tightly sealed container, like a jar. Stored this way, it can last several years. If you want to turn your harvest into flour, store it in a closed container away from light or heat.
Many of the insects that attack corn also attack sorghum. Without Bt traits, controlling leaf-feeding insects is essential for sorghum. Sugarcane aphids is a common type of insect that can spread diseases such as the barley yellow dwarf virus. Sorghum midge and sorghum webworm could potentially be a problem for producers. If you want to prevent insect damage, choose a hybrid with good insect tolerance and properly treat the seed. However, as the season moves forward and the impact of the first round of insecticides decreases, issues with pests can occur.
The anthracnose, grain mold, head blight, ergot, bacterial leaf stripe, and rust are the most common diseases affecting sorghum in Florida. Anthracnose can more than halve crop yields, and head mold can produce harmful or fatal mycotoxins. Yield loss from stalk rot pathogens, such as charcoal rot, is the most common type of loss. The best ways to help prevent fungal and bacterial diseases of sorghum are to plant resistant hybrids, rotate to non-host crops, and practice tillage.