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Onions and potatoes companion planting is one of the most common pairings in home vegetable gardens, and for good reason. Both crops are members of different families, both want full sun and loose, well-drained soil, and both can share a bed without competing too hard for nutrients if you space and feed them correctly. The catch is that the pairing only works well when you choose the right supporting supplies, varieties and layout. This guide looks at seven picks that help you make that combination succeed, along with the criteria we used to choose them and the practical details you need before you buy.

Our selection criteria focused on five things: how well each item fits a mixed onion and potato bed, whether it addresses a real problem gardeners run into with these two crops (pests, uneven moisture, crowding and soil fertility), the clarity of its manufacturer specifications, the general reputation of the brand, and recurring patterns in owner feedback. We did not test any of these products ourselves. Where we describe performance, we are relying on published specifications and on the kinds of experiences gardeners commonly report.

Our Top Picks

Quick Comparison

Product Best for Key feature
Hoss Tools Long Handle Garden Tool Set Weeding between onion and potato rows Long-handled, lightweight steel tools
Espoma Organic Potato-tone Feeding potatoes with balanced nutrients Organic granular fertilizer for root crops
Espoma Garden-tone General bed fertility shared by both crops Slow-release organic blend
Dig Corporation Potato Hilling Tool Hilling potatoes without disturbing onions Designed for soil mounding around stems
Fiskars Ergonomic Hand Trowel Precise planting of onion sets and seed potatoes Comfortable grip and sharp, narrow blade
Gardener’s Supply Company Soaker Hose Even moisture for both crops in one bed Low-pressure drip-style watering
Bonide Diatomaceous Earth Insect Killer Managing crawling pests near potato foliage Mineral-based dust for soft-bodied pests

Hoss Tools Long Handle Garden Tool Set

This set suits gardeners with a mixed bed who want to weed and cultivate without stepping on or leaning over the plants. Onions have shallow, easily damaged roots, and potatoes can be disturbed when you work the soil deeply, so long handles and a light touch help keep both crops intact.

Key specs

  • Long-handled design intended to reduce bending
  • Steel hoe, cultivator and trowel heads, per manufacturer listings
  • Lightweight construction for repeated use

Pros

  • Reduces back strain during routine weeding
  • Useful for shallow cultivation around onion bulbs
  • Versatile for other vegetable beds

Cons

  • Long handles can be awkward in very narrow beds
  • Thin-blade tools may bend if forced into compacted clay

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Espoma Organic Potato-tone

Potatoes are heavy feeders, especially for potassium, and this organic granular fertilizer is aimed at root and tuber crops. It is a good choice for the potato side of the bed when you want a feed that is less likely to push excessive leafy growth at the expense of tubers.

Key specs

  • Organic granular formulation
  • Formulated for root and tuber vegetables, per manufacturer
  • Application rates listed on the bag, typically worked into the soil before planting

Pros

  • Organic and approved for use in many organic gardening programs
  • Slow release supports steady feeding through the season
  • Easy to apply by hand

Cons

  • Slower to show results than synthetic fertilizers
  • Over-application can still cause problems, so measure carefully

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Espoma Garden-tone

If you want one general-purpose organic fertilizer for the whole bed, this option works for both onions and potatoes. It is a practical pick for gardeners who grow many vegetables and prefer not to buy a separate product for each crop.

Key specs

  • Organic, slow-release granular blend
  • Intended for vegetables, flowers and general garden use
  • Works into the top several inches of soil before planting

Pros

  • Covers both crops with one product
  • Gentle on soil biology when used as directed
  • Easy to store and measure

Cons

  • A general blend may not fully match the specific needs of heavy potato feeding
  • Results depend on soil test levels, which the product cannot correct on its own

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Dig Corporation Potato Hilling Tool

Hilling, the practice of mounding soil around potato stems, is important for protecting developing tubers from light and for improving yield. This type of hilling tool lets you mound soil neatly without digging around onion bulbs that sit at the surface.

Key specs

  • Designed for soil mounding around plant stems
  • Hand-held form for working in confined rows
  • Manufacturer-specified tool dimensions vary by model; check listing before ordering

Pros

  • Makes consistent hilling easier than using a hand trowel alone
  • Helps keep tubers covered and protected from greening
  • Useful in both raised beds and in-ground rows

Cons

  • Single-purpose tool that does little outside hilling work
  • Less useful in very shallow raised beds where hilling depth is limited

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Fiskars Ergonomic Hand Trowel

Onion sets and seed potatoes both need accurate placement, and a narrow, comfortable trowel helps you set each one at the right depth without crowding its neighbor. This is a good everyday pick for beginners and for gardeners who plant in tight grids.

Key specs

  • Ergonomic, cushioned grip
  • Stainless or steel blade, depending on model
  • Compact size for working between plants

Pros

  • Comfortable for extended planting sessions
  • Precise enough for onion sets spaced a few inches apart
  • Widely available and well known from the brand

Cons

  • Small trowels are slow for turning large areas of soil
  • Blade can bend if used to pry rocks or roots
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Gardener’s Supply Company Soaker Hose

Onions prefer consistent moisture but dislike waterlogged soil, while potatoes need steady water during tuber formation. A low-pressure soaker hose delivers water at the root zone, which helps both crops without wetting foliage excessively, a habit that can encourage disease.

Key specs

  • Porous hose designed for slow, even water release
  • Low-pressure operation, typically from a standard spigot
  • Available in multiple lengths; check manufacturer listing for dimensions

Pros

  • Delivers water at soil level, reducing leaf wetness
  • Works well along the row between onions and potatoes
  • Simple to set up and store

Cons

  • Output can be uneven over very long runs
  • Porous hoses can clog if you have hard water or sediment
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Bonide Diatomaceous Earth Insect Killer

Potato plants attract pests such as flea beetles and some crawling insects, and gardeners sometimes look for mineral options that can be dusted on foliage and soil. Diatomaceous earth is a mineral powder used in this way, though it must be applied carefully and reapplied after rain.

Key specs

  • Mineral-based diatomaceous earth formulation
  • Dust application to foliage and soil surfaces
  • Label directions specify use and reapplication guidance

Pros

  • Mineral product that many gardeners use in organic programs
  • Useful as one part of an integrated pest management approach
  • Easy to apply with a duster

Cons

  • Loses effectiveness when wet and must be reapplied after rain
  • Can irritate eyes and lungs during application; wear a dust mask and eye protection
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Buying Guide

Selection criteria for onions and potatoes companion planting

Before buying any supplies, it helps to understand why these two crops are paired. Onions release sulfur compounds from their roots that some gardeners believe deter certain pests, though the evidence is mostly anecdotal and not conclusive. Potatoes, meanwhile, are often planted in the same rows because they use space and nutrients differently and because both are cool-season staples that can be planted at similar times in many regions. The practical benefit is mostly about efficient use of space and easier pest observation, not a guaranteed pest shield.

Important features to look for

  • Tools with long handles or narrow heads help you work between plants without damaging shallow onion roots.
  • Slow-release fertilizers match the steady feeding needs of both crops better than fast-acting formulas.
  • Low-pressure irrigation keeps soil moist without splashing soil-borne disease onto leaves.
  • Clear manufacturer labeling on any pest-control product, including application rates and safety information.

Specs to check before you buy

  1. Check the manufacturer’s stated application rate for fertilizers and compare it to your bed size.
  2. Confirm the length and flow guidance for any soaker hose against your bed dimensions.
  3. Read the tool head dimensions if you plan to work in tight spacing.
  4. Review the label for any dust or spray to confirm it is labeled for use on your crops.

Choosing by need

  • Small raised bed with mixed rows: a trowel, a long-handled hand tool and a soaker hose cover most tasks.
  • Heavy potato yield goals: add a hilling tool and a potato-focused fertilizer.
  • Organic gardening: prioritize organic fertilizers and mineral-based pest options, and follow label directions closely.
  • Beginners: start with a comfortable trowel and a general-purpose fertilizer before adding specialty tools.

Things to watch out for

  • Do not assume companion pairings will solve pest problems. Monitor plants regularly.
  • Avoid planting onions too close to peas or beans, which is a separate and well-documented consideration.
  • Over-fertilizing either crop can cause leafy growth at the expense of bulbs and tubers.
  • Soil that stays wet can encourage rot in both crops, so good drainage matters more than any single product.

For a broader look at how these crops fit into planning, see Companion Planting with Potatoes: 9 Best Plants and 5 to Avoid and Companion Planting for Onion: 8 Best Pairings and What to Avoid. If you are still deciding how the pairing fits your overall plan, What Does Companion Planting Mean? Pairings and Pitfalls explains the basic principles.

FAQ

Do onions and potatoes actually help each other grow?

The evidence is mixed. Many gardeners report good results when planting them together, and the pairing uses space efficiently. However, controlled research showing strong growth benefits is limited, so treat the combination as a practical arrangement rather than a guaranteed boost.

How far apart should onions and potatoes be planted?

Spacing depends on the variety and your bed design, but a common approach is to leave potatoes about 12 inches apart within rows and onions about 4 inches apart. Check the spacing guidance on your seed potato or onion set packaging and adjust for your conditions.

Can onions prevent potato pests?

Onions are sometimes said to deter certain insects, but this is not reliably proven. Use regular scouting, handpicking and, where appropriate, labeled products rather than relying on the companion effect alone.

Should I hill potatoes around onions?

You can hill potatoes, but work carefully around onion bulbs, which sit near the soil surface. Use a hilling tool or a hand trowel and avoid pulling soil directly over the onion necks.

When should I plant onions and potatoes together?

Both are cool-season crops, so planting times often overlap. Onion sets and seed potatoes are commonly planted in early spring once the soil is workable, though exact dates depend on your local frost pattern and extension service guidance.

What should I avoid planting near onions and potatoes?

Keep onions away from peas and beans, and keep potatoes away from tomatoes, which share disease risks such as blight. Good rotation and spacing reduce these problems more than any single companion choice.

Is diatomaceous earth safe to use around vegetables?

Diatomaceous earth is a mineral product often used in organic gardening, but you should follow the label, wear protective gear while applying, and reapply after rain. Consult your local extension office if you have questions about pest management in your area.

Conclusion

Onions and potatoes companion planting works best when you pair the crops with the right supporting supplies and a clear plan. The Hoss Tools Long Handle Garden Tool Set and Fiskars Ergonomic Hand Trowel suit gardeners who want to work carefully between plants. The Espoma Organic Potato-tone is a good match if potatoes are your priority, while Espoma Garden-tone covers general bed fertility for both crops. The Dig Corporation Potato Hilling Tool helps with tuber protection, the Gardener’s Supply Company Soaker Hose supports even moisture, and the Bonide Diatomaceous Earth Insect Killer is an option for managing crawling pests when used according to label directions. Choose the items that match your bed size, your yield goals and your gardening approach, and check the manufacturer specifications before you buy.