All About Growing Sorghum

Growing sorghum is generally a rewarding and low-maintenance experience because the plants are heat-loving, drought-tolerant, and grow quickly once established. Watching the tall stalks and large seed heads develop can be impressive, especially with sweet or forage types that may reach 2–4 meters tall. Compared to crops like corn, sorghum usually requires less water and handles hot, dry conditions better, making it a good choice for beginner gardeners in warm climates.

Types of Sorghum

Type of Sorghum	Distinctive Characters	Main Uses
Grain Sorghum (Milo)	Short plants (0.6–1.5 m), large seed heads, bred for high grain production. Seeds may be white, red, bronze, brown, or black.	Human food, flour, porridge, livestock feed, poultry feed, gluten-free products.
Sweet Sorghum	Tall plants (2–5 m) with thick, juicy stalks rich in sugar. Similar in appearance to sugarcane.	Syrup, molasses, biofuel, ethanol production, forage.
Forage Sorghum	Very tall (2–4 m), coarse stems, produces abundant leafy biomass.	Silage, hay, livestock grazing, green chop feed.
Sudangrass	Fine stems, rapid growth, excellent regrowth after cutting, shorter season than forage sorghum.	Pasture, hay, rotational grazing, soil improvement.
Sorghum–Sudangrass Hybrid	Cross between forage sorghum and sudangrass; combines high yield with good regrowth.	Grazing, silage, hay, cover crop.
Broomcorn Sorghum	Produces long, fibrous seed-head branches (up to 90 cm long). Tall plants (2–4.5 m).	Traditional brooms, brushes, crafts, ornamental use.
Biomass Sorghum	Extremely tall plants with thick stalks and very high dry-matter production.	Bioenergy, biomass fuel, industrial uses, renewable energy feedstock.
Sorghum-Almum (Columbusgrass)	Perennial or semi-perennial type with vigorous growth and strong regrowth ability.	Grazing, forage, pasture improvement.

HOW TO GROW SORGHUM

Quick Beginner Tips

Start with grain sorghum if you want an edible crop.
Sow directly into warm soil after frost danger has passed.
Keep weeds under control during the first month.
Protect ripening seed heads from birds.
Harvest only when grain is fully mature and dry for best storage life.

1. Choose a Variety

Best Choices for Beginners

Sorghum Type	Popular Varieties
Grain Sorghum	White Sorghum, Red Milo, Black Sorghum
Sweet Sorghum	Dale, Rox Orange, Honey Drip
Forage Sorghum	Superdan, Jumbo, Mega Sweet
Broomcorn	Evergreen, Black Spanish
Biomass Sorghum	ES5200, Blade ES series

2. Growing Timeline

Month	Growth Stage	Tasks
August	Preparation	Choose a sunny location, remove weeds, improve soil with compost, and ensure good drainage.
September	Planting & Germination	Sow seeds directly after soil warms above 18°C. Keep soil lightly moist until seedlings emerge.
October	Seedling Growth	Thin seedlings to proper spacing, control weeds, and water during dry periods.
November	Rapid Vegetative Growth	Plants grow quickly in height. Apply nitrogen-rich fertilizer if needed and monitor for pests.
December	Stem Development & Leaf Growth	Continue watering during hot weather. Keep area weed-free and inspect for aphids and armyworms.
January	Flowering & Pollination	Seed heads emerge and flowering begins. Ensure plants receive adequate moisture during this critical stage.
February	Grain Filling	Seeds develop and mature. Reduce watering as seed heads begin drying. Protect from birds if growing grain sorghum.
March	Harvest	Harvest when seed heads are dry and hard, and grains cannot be dented easily with a fingernail.
April	Post-Harvest	Dry grain thoroughly, clean storage containers, and remove crop residues from the garden.

3. Growing Conditions

Well-drained loam or sandy loam (5.8-7.5ph).
6–8+ hours full sun daily
Warm to hot weather; frost-free growing season (25–35°C; Seedlings tolerate light frost)

4. Planting

Best Planting Time in Sydney: Spring to summer.

0. Prepare soil: Remove weeds and mix compost into soil

1. Planting Steps

From Seeds

Sorghum is usually direct-seeded, not transplanted.

Step Details
Wait until soil temperature reaches at least 18°C.
Prepare loose, weed-free soil enriched with compost.
Sow seeds directly into the garden.
Plant seeds 2–4 cm deep, 15–20 cm between plants, 45–75 cm between rows.
Water gently after sowing.
Thin seedlings to 15–20 cm apart when 10–15 cm tall.

2. POT Planting

Sorghum can be grown in containers, but larger pots produce healthier plants, taller stalks, and better grain yields. Because sorghum develops a substantial root system and can reach 1–4 m tall depending on the variety, container size matters.

Best Varieties for Pots

Variety	Type	Height	Why It Works in Pots
Mennonite Sorghum	Grain	1–1.5 m	Compact size and reliable grain production.
Black Amber Sorghum	Ornamental/Grain	1–1.8 m	Attractive dark foliage and manageable height.
White Sorghum (dwarf strains)	Grain	1–1.5 m	Easier to support and harvest in containers.
Honey Drip	Sweet	1.8–2.5 m	One of the smaller sweet sorghums; suitable for large pots.
Dale	Sweet	2–3 m	Productive sweet sorghum if grown in a large container.
Maya Ornamental Sorghum	Ornamental	1–1.5 m	Compact, colorful seed heads, excellent for decorative pots.
Broomcorn ‘Evergreen’	Broomcorn	1.5–2 m	Smaller than many broomcorn types and suitable for large containers.

Pot Size Guide

Sorghum Type	Minimum Pot Size	Ideal Pot Size	Plants per Pot
Dwarf Grain Sorghum	30 cm diameter × 30 cm deep (10–15 L)	40–45 cm diameter × 40 cm deep (20–30 L)	1–3 plants
Standard Grain Sorghum	40 cm diameter × 40 cm deep (20 L)	50–60 cm diameter × 45–50 cm deep (35–50 L)	2–4 plants
Sweet Sorghum	45 cm diameter × 45 cm deep (30 L)	60 cm+ diameter × 50 cm+ deep (50–75 L)	1–2 plants
Broomcorn Sorghum	45 cm diameter × 45 cm deep (30 L)	60 cm diameter × 50 cm deep (50 L+)	1–2 plants

5. Watering

Growth Stage	Watering Requirement
Germination	Keep soil consistently moist.
Seedling Stage	Water deeply 1–2 times weekly.
Vegetative Growth	Moderate watering during dry weather.
Flowering & Grain Fill	Most critical period; avoid drought stress.
Maturity	Reduce watering as seed heads dry.

Tips:

Water deeply rather than frequently.
Avoid waterlogged soil.
Mulch around plants to conserve moisture.

6. Supporting & Pruning

Supporting:

Situation	Support Needed?
Home garden grain sorghum	Usually no
Sweet sorghum (tall varieties)	May benefit from staking in windy areas
Exposed sites	Windbreaks recommended
Container growing	Stake if plants become top-heavy

Pruning: Sorghum naturally develops a strong central stalk and requires minimal pruning.

Task	Recommendation
Routine pruning	Not required
Remove damaged leaves	Yes, as needed
Remove seed heads	Only if growing for decorative use
Thin overcrowded plants	Yes, during seedling stage

7. Feeding

Time	Fertilizer
Before Planting	Compost or well-rotted manure
4–6 Weeks After Emergence	Nitrogen-rich fertilizer
Before Flowering	Balanced fertilizer if growth is weak
During Grain Fill	Usually no additional feeding needed

8. Pollination

Flowering heads release pollen that is easily carried by wind.

Aspect	Details
Pollination Type	Primarily self-pollinated
Pollination Agent	Wind assists pollen movement
Need Multiple Plants?	Not necessary but beneficial
Hand Pollination	Rarely required

9. Common Problems

Problem	Symptoms	Solution
Birds	Missing or damaged seeds	Use netting, reflective tape, or scare devices
Aphids	Clusters of insects on leaves	Spray with water or insecticidal soap
Armyworms	Chewed leaves	Hand-pick or use biological controls
Cutworms	Seedlings cut at soil line	Use collars around young plants
Root Rot	Wilting despite wet soil	Improve drainage and avoid overwatering
Leaf Spot	Brown or reddish spots on leaves	Improve airflow and remove infected leaves
Smut Disease	Black powdery masses in seed heads	Remove affected plants and rotate crops
Weeds	Reduced growth and yield	Mulch and weed regularly

10. Harvesting

Grain Sorghum

Sign	Description
Seed heads dry	Heads turn brown or tan
Grains hard	Cannot easily dent with fingernail
Leaves drying	Lower leaves begin to dry naturally

Harvest Steps:

Cut mature seed heads with pruners.
Place in a dry, airy location.
Allow additional drying if needed.
Separate grains by rubbing or threshing.

Sweet Sorghum

Harvest Indicator	Description
Stalks fully grown	Thick and juicy
Seeds in soft dough stage	Maximum sugar content

Cut stalks near ground level and process promptly for syrup or juice.

11. Post Harvesting Process

Grain Sorghum

Step	Process
Drying	Dry seed heads until grain moisture is below 13%
Threshing	Remove grain from seed heads
Cleaning	Remove chaff and debris
Final Drying	Ensure grain is completely dry
Storage	Store in airtight containers

Sweet Sorghum

Step	Process
Harvest stalks	Cut at maturity
Strip leaves	Remove foliage
Crush stalks	Extract juice
Process quickly	Make syrup or ferment for other uses

11. Storage