What Not to Plant Near Potatoes? 10 Plants to Avoid Plus Better Alternatives

Introduction: Why your potato neighbors matter

If you’ve ever typed what not to plant near potatoes? you already know one little mistake can wipe out a harvest. Potatoes are picky neighbors, because nearby plants can spread diseases like late blight and early blight, invite shared pests such as the Colorado potato beetle, or steal nutrients and light as they grow. I’ve seen gardeners lose tubers because tomatoes and peppers, both Solanaceae, passed on the same fungal problems. Tall crops like corn can shade plants and cut yields, while some ornamentals may release chemicals that stunt root growth. In the next sections you’ll get ten specific plants to avoid, the real reasons they cause trouble, and easy, practical swaps plus spacing tips that actually protect your potato crop.

Quick answer: The top things not to plant near potatoes

Quick answer to "what not to plant near potatoes?" Here are the top offenders, with one short reason each.

• Tomatoes, peppers, eggplant, same family, spread late blight and shared pests.
• Other potatoes or where potatoes grew last year, disease and nematode buildup.
• Cucumbers, squash, pumpkins, attract beetles and create heavy foliage competition.
• Sunflowers, draw Colorado potato beetles and other pests.
• Strawberries and raspberries, share soil fungi like Verticillium wilt.
• Fennel, releases growth-inhibiting compounds that stunt nearby crops.
• Corn, tall and hungry for nutrients, it shades and competes with tubers.

How bad neighbors hurt potato yields and health

Bad neighbors hurt potatoes in five clear ways, and knowing them answers the common question what not to plant near potatoes? First, disease spread. Plant tomatoes or eggplants next to potatoes and you invite late blight and common scab across the bed, because Solanaceae share pathogens and nematodes. Second, shared pests. Colorado potato beetles and aphids move easily between nightshades, cutting yields fast. Third, nutrient competition. Corn, squash, and other heavy feeders steal nitrogen and potassium, leaving tubers small and undernourished. Fourth, allelopathy. Black walnut trees and certain cover crops release compounds that stunt potato roots, so keep potatoes well away from walnut roots. Fifth, shading. Tall plants like sunflowers or corn reduce tuber size by blocking light. Practical fixes, rotate crops for three years, space beds apart, and avoid planting other nightshades nearby.

10 plants you should not plant near potatoes, and why

If you’re asking what not to plant near potatoes? here are 10 clear no nos, with garden-level reasons and simple alternatives you can use next season.

1. Other Solanaceae, such as tomatoes, peppers, eggplant, and tomatillos.
   They share late blight and blight spores travel easily, so diseases and pests move between them. Plant potatoes at least two beds away from any nightshade family crops, or rotate those crops into different parts of the garden.

2. Squash family, including pumpkins, zucchini, cucumbers, and melons.
   Vining growth makes a tangled mess, they compete for water and nutrients, and cucumber beetles can spread bacterial wilt. Instead plant a low-growing green manure or bush beans between potato rows.

3. Sunflowers and tall ornamentals like corn.
   Tall stems shade tubers during peak sun, reducing yields, and they can harbor pests that migrate to potatoes. Keep potatoes in full sun, with at least two meters of clearance from tall plants.

4. Strawberries.
   Potatoes and strawberries share soil diseases such as Verticillium wilt and certain nematodes, so yields drop when grown close. Use that bed for annuals like beans or beets after removing potatoes.

5. Fennel.
   Fennel releases allelopathic compounds that inhibit growth of many vegetables, potatoes included. Never plant fennel inside or next to potato rows. Plant fennel in a dedicated pot or isolated herb strip.

6. Carrots and parsnips.
   Root vegetables attract wireworms and root maggots that feed on tubers. If you want roots nearby, use trap crops or sticky traps for wireworms, otherwise keep carrots two to three meters away.

7. Brassicas, such as cabbage, broccoli, kale, and cauliflower.
   They are heavy feeders and can draw down nitrogen while inviting certain shared pests. If you must pair them, stagger planting times and boost soil fertility with compost prior to planting potatoes.

8. Raspberries and other brambles.
   Perennial roots and suckers compete for moisture, and brambles make crop rotation and soil sanitizing difficult. Keep bramble patches at the far edge of the garden, away from potato production beds.

9. Planting potatoes in the same bed year after year.
   This invites build up of soil-borne blight, scab, and nematodes. Rotate potatoes to a different bed for at least two to three years, and follow with a nitrogen fixing crop like beans.

10. Walnut and other juglone producing trees.
    Black walnut releases juglone, a toxin that stunts many garden plants. Avoid planting potatoes within the tree dripline, and preferably keep them 10 to 15 meters away from mature walnuts.

Follow these rules, and you’ll avoid most common disease and pest problems related to plant placement. When in doubt, rotate crops and use companion plants like marigolds or bush beans to protect potato beds.

Better companion plants to grow near potatoes

If you still ask, what not to plant near potatoes? try these safe companions instead, they boost yield and cut pests.

1. Beans, they fix nitrogen, plant in alternating rows, sow after potatoes are established.
2. Marigolds, they suppress nematodes and deter beetles, plant every 10 to 12 inches around potato beds.
3. Garlic and chives, repel aphids and deter fungal problems, tuck bulbs at row edges.
4. Nasturtiums, act as a trap crop for aphids and flea beetles, sow from seed near potato ends.
5. Dill and cilantro, attract predatory wasps and hoverflies that eat potato pests, let a few plants flower.
6. Clover, a living mulch that adds nitrogen and prevents soil erosion, overseed between rows in spring.
7. Borage, attracts pollinators and is reputed to improve potato vigor, plant a few plants per bed.

Practical bed layout, spacing, and crop rotation tips

Use 4 foot wide beds for easy access, put two staggered rows of potatoes down the center, then reserve edges for safe companions like beans or marigolds. Space seed pieces about 12 inches apart in-row, keep rows roughly 30 inches apart, and plant 3 to 4 inches deep. When plants reach 6 inches, hill soil to cover stems, repeating as they grow.

If you wonder what not to plant near potatoes, keep tomatoes, peppers, and eggplants out of the same bed for at least three years, because they share diseases and pests. Also avoid cucumbers and fennel directly next to potatoes.

Rotate beds on a 3 to 4 year timeline. Simple plan for four beds works well, year 1 potatoes in bed A, year 2 legumes in A to restore nitrogen, year 3 brassicas or leafy greens, year 4 a cover crop or small grain to break pest cycles. Move potatoes to the next bed each season, and record locations on a map so you do not repeat the same spot too soon. This layout and rotation cuts disease pressure and keeps yields steady.

Conclusion and quick checklist before you plant

Quick final thoughts, then a simple 5 step checklist you can use before you plant.

If you asked what not to plant near potatoes? put nightshade cousins first, tomatoes and peppers, then other high-risk neighbors like cucurbits when beet pressure is high, and fennel which inhibits growth. Rotate crops, choose companion plants, and keep foliage airflow to reduce blight.

5 step pre-plant checklist

1. Soil test and pH, aim for 5.8 to 6.5, add lime or sulfur as needed.
2. Rotate, avoid planting potatoes where solanaceous crops grew for 2 to 3 years.
3. Certified seed potatoes only, no supermarket spuds that may carry disease.
4. Space for airflow, at least 12 inches between rows, remove debris and volunteer plants.
5. Companion plan, include beans, marigolds, and horseradish to deter pests.

Main takeaways, in two lines: avoid close planting with tomatoes and other nightshades, practice rotation and sanitation, and pick companions that boost health rather than invite disease.