Broccoli vs Onion

Side-by-side plant comparison — which is right for your garden?

Broccoli

Brassica oleracea var. italica

Brassicaceae · vegetables

EdibleMedium Maintenance

Onion

Allium cepa

Amaryllidaceae · vegetables

EdibleDeer ResistantLow Maintenance

Hardiness Zone Range

Broccoli (Zones 2-11)

Onion (Zones 3-9)

Overlap: Both grow in zones 3–9

Detailed Comparison

Feature	Broccoli	Onion
Scientific Name	Brassica oleracea var. italica	Allium cepa
Family	Brassicaceae	Amaryllidaceae
Category	vegetables	vegetables
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧💧 Medium
Soil	Rich, Well-drained	Rich, Well-drained
Height	2'	1' 6"
Spread	1' 6"	4"
Bloom Season	Spring, Fall	Summer
Bloom Color	Yellow (if bolted)	White
Growth Rate	Medium	Medium
Native Region	Mediterranean	Central Asia
Maintenance	Medium	Low

Special Traits

Broccoli

Yes — EdibleNo — Deer ResistantNo — Drought Tolerant

Onion

Yes — EdibleYes — Deer ResistantNo — Drought Tolerant

Care Tips

Broccoli

✓Transplant 2-3 weeks before last frost.
✓Harvest main head before yellow flowers open.
✓Side shoots keep producing for weeks.
✓Row cover protects from cabbage worms.

Onion

✓Match variety to your latitude — long-day for north, short-day for south.
✓Plant sets or transplants for easiest results.
✓Stop watering when tops fall over.
✓Cure for 2 weeks before storing.

Which Plant Is Right for Your Garden?

Choose Broccoli if you don't mind medium maintenance. It thrives in full sun with medium water in zones 2–11.

Choose Onion if you want a low-maintenance plant, and want deer resistance. It thrives in full sun with medium water in zones 3–9.

Plant them together? Both overlap in zones 3–9. They share similar sun requirements (full sun), making them potential garden companions.

View BroccoliProfile →View OnionProfile →

Frequently Asked Questions

Can Broccoli and Onion grow in the same hardiness zone?

Broccoli grows in USDA zones 2-11, while Onion grows in zones 3-9. Both plants can grow together in zones 3 through 9.

Do Broccoli and Onion have the same sun and water needs?

Broccoli needs full sun and medium water, while Onion needs full sun and medium water. They share similar growing requirements and can be planted in the same bed.

Which grows taller, Broccoli or Onion?

Broccoli grows taller at 2' compared to Onion at 1' 6". Broccoli spreads 1' 6" while Onion spreads 4".

Are Broccoli and Onion deer resistant?

Onion is deer resistant, but Broccoli is not. If deer are a concern, Onion is the better choice, or protect Broccoli with fencing.

Which is easier to maintain, Broccoli or Onion?

Broccoli has medium maintenance while Onion has low maintenance. Onion may be easier for beginning gardeners to manage.

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Detailed Comparison

Feature	Broccoli	Onion
Scientific Name	Brassica oleracea var. italica	Allium cepa
Family	Brassicaceae	Amaryllidaceae
Category	vegetables	vegetables
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧💧 Medium
Soil	Rich, Well-drained	Rich, Well-drained
Height	2'	1' 6"
Spread	1' 6"	4"
Bloom Season	Spring, Fall	Summer
Bloom Color	Yellow (if bolted)	White
Growth Rate	Medium	Medium
Native Region	Mediterranean	Central Asia
Maintenance	Medium	Low

Care Tips

Broccoli

✓Transplant 2-3 weeks before last frost.
✓Harvest main head before yellow flowers open.
✓Side shoots keep producing for weeks.
✓Row cover protects from cabbage worms.

Onion

✓Match variety to your latitude — long-day for north, short-day for south.
✓Plant sets or transplants for easiest results.
✓Stop watering when tops fall over.
✓Cure for 2 weeks before storing.

Which Plant Is Right for Your Garden?

Choose Broccoli if you don't mind medium maintenance. It thrives in full sun with medium water in zones 2–11.

Choose Onion if you want a low-maintenance plant, and want deer resistance. It thrives in full sun with medium water in zones 3–9.

Plant them together? Both overlap in zones 3–9. They share similar sun requirements (full sun), making them potential garden companions.

Frequently Asked Questions

Can Broccoli and Onion grow in the same hardiness zone?

Broccoli grows in USDA zones 2-11, while Onion grows in zones 3-9. Both plants can grow together in zones 3 through 9.

Do Broccoli and Onion have the same sun and water needs?

Broccoli needs full sun and medium water, while Onion needs full sun and medium water. They share similar growing requirements and can be planted in the same bed.

Which grows taller, Broccoli or Onion?

Broccoli grows taller at 2' compared to Onion at 1' 6". Broccoli spreads 1' 6" while Onion spreads 4".

Are Broccoli and Onion deer resistant?

Onion is deer resistant, but Broccoli is not. If deer are a concern, Onion is the better choice, or protect Broccoli with fencing.

Which is easier to maintain, Broccoli or Onion?

Broccoli has medium maintenance while Onion has low maintenance. Onion may be easier for beginning gardeners to manage.