Companion Plants for Potatoes

Why companion planting matters for potatoes

Colorado potato beetles defoliate potato plants faster than almost any other garden pest—a full infestation can strip a plant to bare stems in under a week, and the beetles are resistant to many common pesticides in most US states.

The beetle (Leptinotarsa decemlineata) is present in all lower 48 states and overwinters in the soil near last year’s potato planting. In spring, adults emerge and immediately begin feeding on potato foliage. A single female lays 300–500 eggs per season. The larvae feed on leaf undersides and are the most destructive stage.

Companion planting works on two mechanisms: some plants emit volatile chemicals that deter pest insects, and others attract beneficial predators that reduce pest populations. Neither mechanism eliminates pests completely—but reducing pressure through companions means the pest population stays below the threshold that causes serious yield loss.

The companion planting strategy that actually works in field conditions combines several approaches: pest deterrents at row ends and bed corners, beneficial insect habitat nearby, and physical barriers where chemical deterrence isn’t enough.

Best companion plants for potatoes

Horseradish

Horseradish (Armoracia rusticana) is the most widely recommended potato companion and the one with the strongest supporting evidence. The volatile compounds in horseradish roots and leaves—primarily isothiocyanates—are documented to repel Colorado potato beetles.

How to use it:

• Plant one horseradish crown 18 inches outside each corner of the potato bed
• Horseradish is a perennial that returns each year—plant it once in a permanent spot
• Keep it outside the potato bed, not within it. Horseradish spreads aggressively and competes with potato plants if planted too close

Horseradish grows in USDA Zones 3–9 and tolerates most soil types. Once established, it requires no maintenance. The roots can be harvested each fall as a food crop.

Marigolds

Marigolds (Tagetes patula and Tagetes erecta) provide two documented benefits near potatoes. French marigolds suppress root-knot nematodes in the soil through thiophene compounds released by their roots. They also attract hoverflies and parasitic wasps—beneficial insects whose larvae parasitize or prey on Colorado potato beetle eggs and larvae.

Best use:

• French marigolds (Tagetes patula, 8–12 inches) planted as a border around the potato bed
• Plant at 6–8 inch spacing for a continuous border
• Annual—reseed each season
• Start from seed 6–8 weeks before transplant date, or buy transplants

For a full overview of marigold use in companion planting systems, our marigolds guide covers the different species, their pest deterrence properties, and their role in attracting beneficial insects.

Bush beans

The potato-bean combination is one of the oldest companion plantings in American gardening, and there is research backing it up. A study by the University of Maine found that bush beans interplanted with potatoes reduced Colorado potato beetle populations compared to potato monocultures. The mechanism is not fully clear, but bean foliage may confuse beetle navigation by breaking up the scent profile of a large potato planting.

How to plant:

• Interplant bush beans between potato rows, not within them
• Spacing: one row of bush beans between every two potato rows
• Harvest beans before potatoes need hilling—the mounding process disturbs companion plants
• Use bush beans, not pole beans. Pole beans shade potato foliage and reduce yields

The potato-bean combination mirrors the Three Sisters (corn, beans, squash), where each plant benefits the others. See our bean companion plants guide for more on how beans interact with other vegetables.

Catnip

Catnip (Nepeta cataria) contains nepetalactone, a compound that repels several insect pests including aphids, flea beetles, and Colorado potato beetles. It is among the most effective natural repellents available to home gardeners.

How to plant:

• Plant catnip at the ends of potato rows, 12–18 inches from potato plants
• Catnip grows 2–3 feet tall and spreads—contain it or grow in a pot placed at row ends
• Perennial in Zones 3–9—returns each year

The drawback: catnip attracts neighborhood cats, who may roll on and crush nearby plants. Growing it in a bottomless pot sunk into the ground reduces cat damage while still allowing root growth.

Tansy

Tansy (Tanacetum vulgare) has a documented history as a Colorado potato beetle deterrent in organic production. It emits thujone and other volatile compounds that repel beetles. The yellow, button-like flowers also attract predatory insects.

Caution: Tansy spreads aggressively and is toxic to some livestock. Do not plant near animal pastures. Plant in a contained area or manage spreading by deadheading before seed set. It is listed as invasive in some Pacific Northwest counties—check local regulations before planting.

Coriander (cilantro going to seed)

Coriander—cilantro allowed to flower and go to seed—is an excellent beneficial insect habitat plant. The small, umbrella-shaped flowers attract parasitic wasps, ground beetles, and hoverflies that prey on potato pests.

In the vegetable garden, allowing a few cilantro plants to bolt near potato beds provides this habitat without occupying space within the potato planting. Coriander self-seeds readily and comes back each year in most US gardens.

Chamomile

German chamomile (Matricaria chamomilla) is a traditional companion for potatoes in European organic production systems. It improves calcium and potassium availability in the soil as it decomposes, and its flowers attract beneficial insects. Plant at the edges of the potato bed rather than within it.

Companion planting at-a-glance

What not to plant near potatoes

Certain plants actively harm potato performance or increase pest and disease pressure. These should be kept on the opposite side of the garden from potato beds.

Tomatoes and other nightshades

Tomatoes, peppers, and eggplant are in the same plant family (Solanaceae) as potatoes. They share late blight (Phytophthora infestans), the disease that caused the Irish Potato Famine and still devastates home gardens in humid US climates.

When tomatoes and potatoes grow adjacent, late blight spreads between them readily. They also attract the same pests—Colorado potato beetles feed on tomato foliage when potato foliage is unavailable. Rotating both crops away from each other’s previous locations is part of the standard late blight management strategy.

For companion plants that actually help tomatoes (a different list than potatoes), see our tomato companion plants guide.

Fennel

Fennel releases allelopathic compounds from its roots that inhibit the growth of many vegetable plants, including potatoes. Keep fennel in a separate area of the garden, isolated from vegetable beds.

Sunflowers

Sunflowers compete aggressively for water and nutrients and shade potato foliage. Their root exudates may also inhibit potato growth, though the shade competition is the main problem. Keep sunflowers outside the potato production area.

Cucumbers

Cucumber and potato combinations reportedly increase susceptibility to Phytophthora blight in both crops. While not as severe as the tomato-potato combination, they are better kept apart.

Physical companion strategies

Companions are most effective when combined with physical management.

Row covers: Floating row covers (spunbond fabric) physically exclude Colorado potato beetles from reaching plants at all. This is the single most effective non-chemical control for potato beetles. Remove during flowering if your potato variety requires pollination (most do not—potatoes are self-pollinating).

Mulch: Heavy mulch between potato rows suppresses weeds that harbor pests, retains moisture, and keeps soil cool. Straw mulch in potato beds is documented to reduce early blight severity. For mulch options, our best mulch for vegetable garden guide covers materials and application rates for vegetable beds.

Crop rotation: The most important pest management tool for potatoes is rotating out of the same area every 3–4 years. Colorado potato beetles overwinter in the soil near last year’s potato beds. Moving the planting location makes adults travel to find the new planting, which reduces early-season pressure significantly.

How to design a potato bed with companions

A well-designed potato companion planting uses perimeter plantings for pest deterrence and interrow plantings for beneficial insect habitat.

Sample bed layout for a 4×8 foot raised bed:

• Horseradish: one plant outside each corner, 18 inches from bed edge
• French marigolds: continuous border around bed at 8-inch spacing
• Potatoes: 10–12 plants in the main bed (12-inch spacing)
• Coriander: 2–3 plants at the ends of the bed, allowed to flower

For a larger in-ground potato planting (10+ rows):

• Alternate bush bean rows between every two potato rows
• Plant tansy or catnip at row ends
• Establish a marigold border on the south-facing edge of the planting

The companion planting chart at our companion planting chart guide shows which vegetable combinations are beneficial and which are harmful across the full vegetable garden.

Managing Colorado potato beetles alongside companions

Companion plants reduce beetle pressure but rarely eliminate it. In most US gardens, even with good companions in place, manual management is still needed.

Hand picking: Check leaf undersides for yellow-orange egg clusters (laid in groups of 10–30) and crush them. Check for orange larvae and knock into soapy water. This is most effective in early morning when beetles are less active.

Spinosad: An organic-approved insecticide derived from soil bacteria. Effective against Colorado potato beetle larvae; less effective against adults. Apply in early morning when pollinators are inactive.

Neem oil: Applied as a preventative before beetles appear, neem oil (azadirachtin) disrupts beetle feeding and reproduction. Reapply after rain.

For a complete overview of beetle management that includes companion planting as one of several strategies, the Colorado State University Extension publishes updated Colorado potato beetle management recommendations for the mountain west, applicable to most US potato growing regions.

For growing the potato crop itself—spacing, hilling, watering, and harvest timing—our how to plant potatoes guide covers the full growing process.

For the general principles behind how companion planting works—which mechanisms are documented, which are folklore—our companion planting guide explains what the research actually supports.