Collard green benefits significantly from companion planting. The plant's main challenges — Cabbage Worm and Aphid pressure, and the pollination needs that drive fruit set — are directly addressed by the right neighboring plants. Below are the companions with the strongest evidence, their specific benefits, recommended spacing, and the plants to keep collard green away from.
Companion Planting for Collard Greens
Published: April 21, 2026
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Best Companions for Collard Greens
| Companion | Benefit | Spacing |
|---|---|---|
| Onion | Sulfur compounds repel carrot fly, aphids, and fungal disease | 6 in |
| Garlic | Repels aphids, spider mites, and Japanese beetles; antifungal | 6 in |
| Dill | Attracts beneficial wasps and hoverflies when in flower | 12–18 in (remove before flowering) |
| Celery | Deters white cabbage butterfly; shares similar water needs | 12 in |
| Mint | Beneficial pairing with collard green | 12–18 in |
Plants to Avoid Near Collard Greens
| Avoid | Reason |
|---|---|
| Tomato | Shares nightshade diseases with brassicas; both are heavy feeders |
| Strawberry | Share verticillium wilt susceptibility with brassicas |
| Bean | Onion and garlic sulfur compounds stunt bean nitrogen fixation |
Collard Greens in a Raised Bed — Layout
In a standard 4×8 raised bed with collard green as the main crop, plant 18-inch spacing for the primary crop and interplant Onion, Garlic, and Dill around the edges and between rows. Keep Tomato in a separate bed to avoid the competition and disease pressure those pairings create.
When to Plant Companions with Collard Greens
Plant onion with collard green in the cool-season window — both prefer temperatures in the 55 to 70°F range. Cool-season companions can go in at the same time as direct-sown collard green (soil at 45°F minimum) or 1 to 2 weeks ahead of transplants. Herb companions like rosemary and chives are perennials that stay in place year-round. Interplant fast cool-season companions (radish, lettuce) between rows for a quick 30 day harvest before the main crop fills in.
Companion Planting & Collard Green Pest Control
Collard Green’s most common pests — Cabbage Worm, Aphid, Flea Beetle — are directly addressed by the right companions. Onion sulfur compounds repel carrot fly, aphids, and fungal disease. Garlic adds a second defense — repels aphids, spider mites, and japanese beetles; antifungal. These effects are strongest when the companion is planted within 18 inches of the main crop, and when multiple companion species are layered together rather than used singly. Beneficial insects (hoverflies, parasitic wasps, ladybugs) drawn in by companion flowers provide additional control against aphids and caterpillars — flowering companions like dill, borage, and marigold all attract these predators.
Frequently Asked Questions
What is the best companion plant for collard green?
Onion is the best all-around companion for collard green — sulfur compounds repel carrot fly, aphids, and fungal disease. Plant onion 6 in from collard green for the strongest effect. Garlic is a close second — repels aphids, spider mites, and japanese beetles; antifungal.
What should I not plant near collard green?
Avoid Tomato and Strawberry. Tomato shares nightshade diseases with brassicas; both are heavy feeders. Keep these at least 6 feet from your collard green or plant them in a separate bed to avoid the competition and shared pest pressure.
Can I grow collard green and tomato in the same garden?
Yes, in separate beds. Tomato and collard green shares nightshade diseases with brassicas; both are heavy feeders, but placing them 6+ feet apart with a buffer of other crops usually prevents problems. Rotation is also important — don't plant the same family in the same bed two years in a row.
How far apart should companion plants be from collard green?
Pest-deterrent companions like onion work within 12 to 18 inches of collard green. Nitrogen-fixing legumes work at 18 to 24 inches. Trap crops (nasturtiums, for example) need 18+ inch spacing so pests congregate on the trap rather than the main crop. Flowering companions for pollinator attraction can be anywhere in the bed — their bee-attracting effect reaches 10 to 20 feet.
Does companion planting help with cabbage worm on collard green?
Yes, for the specific companions that target Cabbage Worm. Onion and Garlic are documented cabbage worm deterrents and should be planted within 18 inches of collard green. Companion planting is one part of integrated pest management — combine it with floating row covers during peak cabbage worm season and hand-picking for best results.