Emily ParkerBy Emily Parker

Updated November 2026

Companion planting strawberries and onions is one of the simplest ways to make a small bed work harder. Onions release sulfur compounds that can help confuse pests such as aphids and some beetles, while strawberries give you a low, ground-covering crop that uses space the onions leave open. This guide shows you how to lay out the pair, space them correctly and avoid the problems that usually cause disappointment.

Why Strawberries and Onions Work Together

The main benefit is pest pressure. Strawberries attract a range of insects, and onions are often cited by gardeners as a deterrent to aphids and certain other pests that feed on leafy crops. The effect is not guaranteed, and it works best as one part of a broader plan that includes good watering, clean beds and regular inspection.

Shopping for one? See our guide: 6 Best Onions and Potatoes Companion Planting Books and Guides for 2026.

The second benefit is space efficiency. Strawberries spread by runners and form a dense mat, while onions grow upright with narrow foliage. When you plant them in the same bed, the onions fill gaps between strawberry crowns and the strawberries shade the soil around onion bulbs, which helps keep moisture steady.

How to Plant Strawberries and Onions Together

Start with a bed that drains well and gets at least six to eight hours of direct sun. Work in two to three inches of compost before planting, and aim for a loose soil depth of about eight inches.

  1. Plant strawberry crowns in early spring, once the soil can be worked, setting each crown so the top is level with the soil surface.
  2. Space strawberry plants 12 to 18 inches apart in rows, with rows about 30 inches apart if you use the matted row system.
  3. Set onion sets or transplants in the gaps, about 4 to 6 inches from the nearest strawberry crown. Space onions 3 to 4 inches apart.
  4. Water both crops at the base, keeping foliage as dry as possible to reduce disease.
  5. Mulch lightly with straw once the soil warms, pulling it back from strawberry crowns to prevent rot.

Spacing and Layout Details

Onions need less root room than strawberries, so think of them as fillers rather than equal partners. If you plant too many onions too close to the strawberry crowns, both crops compete for nitrogen and water. Leave a clear margin around each crown.

Crop Spacing Planting Time
Strawberry crowns 12 to 18 inches apart Early spring
Onion sets 3 to 4 inches apart Early spring, as soil is workable
Onion transplants 4 to 6 inches apart Early spring

Watering, Feeding and Pest Control

Both crops want consistent moisture, roughly one inch of water per week, but they dislike soggy roots. Water at the soil line in the morning so leaves dry before evening. Onions are shallow-rooted, so keep the top two inches of soil slightly moist during bulb formation.

Feed strawberries with a balanced fertilizer at planting and again after the main harvest. Onions need less nitrogen once bulbs begin to swell, so avoid heavy feeding late in the season. Check the undersides of strawberry leaves weekly for aphids, spider mites or early signs of gray mold, and remove affected foliage promptly.

Common Mistakes to Avoid

  • Planting onions directly against strawberry crowns, which can crowd the plants and invite rot.
  • Overwatering, especially during onion bulb formation, which can lead to soft bulbs.
  • Letting runners spread into onion rows, which makes harvesting and weeding harder.
  • Expecting onions alone to stop all pests. Monitor the bed and act early.
  • Mulching too thickly around strawberry crowns, which traps moisture and encourages disease.

A soil thermometer helps you confirm the bed is warm enough before planting onion sets, which avoids weak early growth. View on Amazon

A drip line or soaker hose keeps water at the root zone and off strawberry foliage. View on Amazon

Clean straw mulch suppresses weeds and keeps berries off the soil. View on Amazon

FAQ

Do onions really keep pests away from strawberries?

Onions may discourage some aphids and other pests, but they are not a complete solution. Gardeners generally report better results when onions are combined with regular inspection and good sanitation.

How far apart should onions be from strawberry plants?

Leave about 4 to 6 inches between onion plants and the nearest strawberry crown. This gives each crop room to root without competing heavily.

Can I plant onions and strawberries in containers?

Yes, but use a container at least 12 inches deep and wide enough to hold several strawberry crowns with onions placed in between. Container beds dry out faster, so check moisture daily in warm weather.

Conclusion

Companion planting strawberries and onions works best when you space the crops with care, keep moisture steady and watch for pests. Start with a well-drained bed, plant in early spring and keep the onions in the gaps rather than crowding the crowns. A little attention through the season will give you cleaner berries and a reliable onion harvest.

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Emily Parker

About Emily Parker

Emily Parker is part of our editorial team and reviews and edits our vegetable & edible gardening guides, checking product details against manufacturer specifications and owner feedback.