Can I Plant Onions and Potatoes Together? A Complete Guide

Onions and potatoes are two of the most popular vegetables to grow in home gardens With their similar soil and sunlight needs, they seem like ideal candidates for companion planting But is it actually a good idea to plant onions and potatoes together?

In this comprehensive guide, we’ll explore the pros and cons of growing onions and potatoes as companion crops. You’ll learn about ideal spacing, timing, layouts, and variety selection to maximize the benefits of interplanting onions and potatoes. We’ll also cover common mistakes to avoid with this pairing

The Benefits of Planting Onions and Potatoes Together

There are several potential benefits to planting onions and potatoes together:

• Pest control Onions help repel common garden pests like aphids, potato beetles, carrot flies, and cabbage worms. The sulfur compounds onions release mask the scent of the potatoes

• Disease suppression: Onions have natural antifungal properties that can help suppress soil fungi and reduce instances of blight infections.

• Efficient use of space: The shallow roots of onions don’t compete much for nutrients and water underground with potato tubers. Above ground, the onion tops die back before the potato vines spread out.

• Enhanced flavor: Some gardeners report potatoes and onions taste better when grown together.

• Weed suppression: Dense plantings of onions helps block light to the soil surface which suppresses weed germination and growth.

When planted properly, onions and potatoes can provide pest control, disease resistance, and yield boosts for each other. But companion planting these crops does require some special considerations.

Key Tips for Planting Onions and Potatoes Together

While onions and potatoes can complement each other as companion plants, here are some important guidelines:

• Mind the spacing: Do not plant onions and potatoes too close together. Overcrowding causes competition for nutrients, sunlight, and moisture which will reduce yields.

• Consider sunlight needs: Onion tops can shade out young potato plants if planted too closely. Be mindful of proper spacing.

• Prep soil carefully: Onions and potatoes both prefer nutrient-rich, loose, well-draining soil. Incorporate several inches of compost before planting.

• Provide consistent moisture: Potatoes and onions need steady soil moisture, so mulch and water diligently. Inconsistent watering adds stress.

• Get the timing right: Potatoes should be planted 2-3 weeks before onions to give them a head start. Onions mature faster than potatoes.

With proper spacing, crop selection, and timing, onions and potatoes can thrive as companion plants. But be sure to avoid overcrowding them.

Ideal Onion Varieties to Grow with Potatoes

Choosing the right onion variety is key to success:

• Scallions – Easy to tuck between potato plants. Harvest while onions are still small.

• Bunching onions – Grow in dense clumps with shallow roots that won’t compete much for space.

• Evergreen bunching – Does not form bulbs so it won’t crowd potatoes underground.

• Chives – Compact perennial with mild onion flavor. Tolerates some shade.

• Garlic chives – Flat leaves with garlic taste. Does well if potatoes shade the area a bit.

Avoid large bulbing storage onion varieties that need more underground space like Copra or Red. Instead opt for compact, quick growing onion types.

Best Potato Varieties for Planting with Onions

When selecting your potato variety, choose shorter season, compact plants including:

• Yukon Gold – Classic yellow potatoes with 65-75 day maturity.

• Red Norland – Early season red potatoes, ready in just 60-70 days.

• French Fingerling – Small oblong tubers with 65-75 day maturity.

• Baby Creamer – Mini rounded potatoes, only 60-70 days to harvest.

• Purple Viking – Dark purple skin and short 65 day maturity period.

Skip long season, spreading potatoes like russets. Focus your selection on quick maturing, compact potato varieties when planting alongside onions.

5 Key Tips for Planting Potatoes and Onions Together

Follow these guidelines when interplanting onions and potatoes:

• Loosen soil and mix in compost/aged manure several weeks before planting.

• Plant seed potatoes first, 2-3 weeks before onion sets or transplants.

• After potato sprouts emerge, plant onions around them, allowing 6-8 inches between plants.

• Hill up soil/mulch around potato stems as they grow to prevent greening of tubers.

• Water deeply and consistently. 1-2 inches per week is ideal.

Proper spacing, timing, soil prep, and care helps avoid competition between onions and potatoes.

Common Mistakes to Avoid with Onion and Potato Companion Planting

When growing onions and potatoes together, be careful to avoid these common errors:

• Planting onions and potatoes too close, causing crowding and reduced yields.

• Using long-maturing onion varieties that need more underground space.

• Planting onions and potatoes at the same time. Potatoes need a 2-3 week head start.

• Allowing onions to shade young potato plants due to close spacing.

• Forgetting to hill potatoes, causing tubers to push up out of the soil.

• Neglecting to water evenly. Fluctuating moisture causes plant stress.

• Inadequate soil preparation with compost/amendments prior to planting.

Paying attention to timing, spacing, plant selection, and care helps maximize success when interplanting onions and potatoes.

Sample Onion and Potato Companion Planting Layouts

Here are two example layouts that enable good yields while avoiding overcrowding:

Onions planted between potato rows:

• Space potato rows 12-18 inches apart
• Once sprouts emerge, plant onion sets in between rows
• Allow 6-8 inches between onion sets and potato plants

Onions along one side of bed:

• Plant two rows of potatoes on one side of bed, spaced 12-18 inches apart
• On the other side, plant a block of onions
• Leave 12-18 inches between potatoes and onions

The key is allowing adequate space between onions and potato plants, both above and below ground.

Growing Onions and Potatoes Together in Containers

It is possible to grow potatoes and onions together in pots, but it’s tricky to avoid overcrowding their roots in a container. Follow these tips:

• Use at least a 15-20 gallon container. Bigger is better.

• Incorporate compost into potting mix to boost nutrition.

• Plant onions around outer edges of container.

• Place 3-4 potato seed pieces in center, leaving 8 inches between onions and potatoes.

• Keep onions trimmed back as they grow to prevent crowding potato plants.

• Continue hilling up potting mix as potato plants get taller.

Even with good spacing, yields are lower when grown this way. In-ground planting is better for robust harvests.

Harvesting and Storing Onions and Potatoes

Here are some tips for harvest and storage:

• Harvest onions after tops yellow and fall over. Cure bulbs for 2 weeks protected from rain before storage.

• Potatoes are ready to dig when vines die back and skins are set. Cure tubers 1-2 weeks in cool, dark place before storage.

• Both onions and potatoes can be stored together in mesh bags or crates in a cool, dark place. Proper curing and storage conditions help both crops last for months!

Frequently Asked Questions about Companion Planting Onions and Potatoes

Here are answers to some common questions about growing onions and potatoes together:

Why shouldn’t onions and potatoes be planted too close together?

Too close proximity causes competition for water, nutrients and space. It leads to reduced yields and growth.

What are the best potato varieties to plant with onions?

Choose short season, compact varieties like Yukon Gold, Red Norland and fingerlings. Avoid long season potatoes.

Is it better to plant onion sets or seeds with potatoes?

Onion sets mature faster, making them a better match for potatoes’ growth timeline. Seeded onions take too long.

Can you plant garlic with potatoes too?

Yes! Garlic makes an excellent companion for potatoes. Follow similar spacing and timing guidelines.

What about shallots or leeks planted with potatoes?

Absolutely! Shallots and leeks are also great companion plants for potatoes. Just be mindful of proper spacing.

The key to success is remembering that both onions and potatoes need sufficient space, above and below ground. Pay close attention to timing, spacing, and variety selection. With smart companion planting, your onion and potato harvest can be plentiful!