Onion vs Tomato

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

Onion

Allium cepa

Amaryllidaceae · vegetables

EdibleDeer ResistantLow Maintenance

Tomato

Solanum lycopersicum

Solanaceae · vegetables

EdibleMedium Maintenance

Hardiness Zone Range

Onion (Zones 3-9)

Tomato (Zones 2-11)

Overlap: Both grow in zones 3–9

Detailed Comparison

Feature	Onion	Tomato
Scientific Name	Allium cepa	Solanum lycopersicum
Family	Amaryllidaceae	Solanaceae
Category	vegetables	vegetables
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧💧 Medium
Soil	Rich, Well-drained	Rich, Well-drained
Height	1' 6"	6'
Spread	4"	3'
Bloom Season	Summer	Summer
Bloom Color	White	Yellow
Growth Rate	Medium	Fast
Native Region	Central Asia	South America
Maintenance	Low	Medium

Special Traits

Onion

Yes — EdibleYes — Deer ResistantNo — Drought Tolerant

Tomato

Yes — EdibleNo — Deer ResistantNo — Drought Tolerant

Care Tips

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.

Tomato

✓Start indoors 6-8 weeks before last frost.
✓Plant deep — bury 2/3 of stem.
✓Consistent watering prevents blossom end rot.
✓Stake or cage indeterminate types.

Which Plant Is Right for Your Garden?

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.

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

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

View OnionProfile →View TomatoProfile →

Frequently Asked Questions

Can Onion and Tomato grow in the same hardiness zone?

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

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

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

Which grows taller, Onion or Tomato?

Tomato grows taller at 6' compared to Onion at 1' 6". Tomato spreads 3' while Onion spreads 4".

Are Onion and Tomato deer resistant?

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

Which is easier to maintain, Onion or Tomato?

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

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Detailed Comparison

Feature	Onion	Tomato
Scientific Name	Allium cepa	Solanum lycopersicum
Family	Amaryllidaceae	Solanaceae
Category	vegetables	vegetables
Sun	☀️ Full Sun	☀️ Full Sun
Water	💧💧 Medium	💧💧 Medium
Soil	Rich, Well-drained	Rich, Well-drained
Height	1' 6"	6'
Spread	4"	3'
Bloom Season	Summer	Summer
Bloom Color	White	Yellow
Growth Rate	Medium	Fast
Native Region	Central Asia	South America
Maintenance	Low	Medium

Care Tips

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.

Tomato

✓Start indoors 6-8 weeks before last frost.
✓Plant deep — bury 2/3 of stem.
✓Consistent watering prevents blossom end rot.
✓Stake or cage indeterminate types.

Which Plant Is Right for Your Garden?

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.

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

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 Onion and Tomato grow in the same hardiness zone?

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

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

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

Which grows taller, Onion or Tomato?

Tomato grows taller at 6' compared to Onion at 1' 6". Tomato spreads 3' while Onion spreads 4".

Are Onion and Tomato deer resistant?

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

Which is easier to maintain, Onion or Tomato?

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