After harvesting the last of my onions, Iâm always excited to plan what comes next. Thereâs still plenty of potential for the garden to grow more food for fresh eating in the fall.
Rotating plant families is important for garden health. For an in-depth look at this topic and how it benefits your garden, check out my detailed guide on Understanding Crop Rotation. Now, let me share what Ive learned from my own garden.
Right after harvesting onions, peas are my go-to choice. These nitrogen-fixing plants not only grow quickly but also replenish nitrogen levels in the soil. I have an article that details the process that beans and soil microbes use to create nitrogen nodules – itâs fascinating!
Fava beans are also great for mild winters and will overwinter in zones 7+ for a June harvest.
Picture a mix of vibrant pink radicchio lettuce and the deep blues, greens, and purples of kale leaves, adding a splash of color to your garden and plate.
Lettuce, bok choy, and spinach are perfect plants to follow onions. If you had tried sowing salad greens earlier in the season only for them to bolt, nowâs your opportunity for a second go at it.
Kale and chard are hardy choices that keep growing even with light frosts. Add a fabric row cover and get cut-and-come-again harvests of fresh greens throughout the winter! I am usually able to harvest from this pair until December or beyond!
They have different nutrient needs and dont deplete the soil as much, adding a fresh, vibrant touch to your garden and meals.
Onions are a kitchen staple prized for their pungent flavor. But once you’ve harvested your onion crop you’re left with empty garden beds and questions about what to plant next.
Proper crop rotation is key for maintaining soil health after onions. By thoughtfully choosing complementary plants from different families, you can disrupt pest and disease cycles while replenishing vital nutrients
In this article, I’ll share 15 excellent options for rotating crops after onion harvest. I’ll also explain why crop sequencing matters and provide growing tips to maximize your success.
Why Crop Rotation Is Crucial After Onions
Onions and other alliums like garlic and leeks are heavy feeders. They rapidly deplete vital nutrients like nitrogen and phosphorus from the soil.
Continuous onion cropping also allows specialized fungi and pests to accumulate, including onion maggots and downy mildew.
That’s why crop rotation is so important. By switching to unrelated plant families, you interrupt disease lifecycles and allow the soil to rebalance its nutrient profile.
Follow a 3-4 year rotation schedule for optimal yields. Avoid sowing onions or related alliums in the same spot for at least 3-4 years.
15 Smart Choices for Planting After Onions
Here are some excellent options for rotating other crops into your onion beds:
1. Tomatoes
As a nightshade, tomatoes help break pest and disease cycles that affect alliums. Their deep roots also improve soil structure.
2. Peppers
Another nightshade, peppers make great onion rotation partners. They occupy garden space when onions are dormant.
3. Broccoli & Cabbages
These heavy-feeding brassicas appreciate the residual nutrients left by onions. They also deter allium-specific pests.
4. Carrots & Parsnips
Carrots and parsnips thrive in lightly fertilized soils after nitrogen-hungry onions. Their feathery foliage improves tilth.
5. Beets
Beets perform well after onions and other heavy feeders. Their wide nutrient needs help rebalance the soil.
6. Sweet Corn
A grass crop, corn is an excellent rotational choice after onions or other alliums. It builds soil structure.
7. Beans & Peas
As nitrogen fixers, legumes like bush beans and peas restore vital nutrients. They also disrupt onion pest cycles.
8. Spinach & Lettuce
Quick-growing greens like spinach and lettuce make good use of residual nitrogen while deterring allium diseases.
9. Radishes
Fast-growing radishes fill empty onion beds quickly for a short-term crop. Their rapid growth outpaces pests.
10. Turnips & Rutabagas
Although susceptible to some onion pests, turnips and rutabagas occupy different seasons thereby avoiding damage. They appreciate the tilth onions provide.
11. Melons & Squash
Sprawling vining plants like cucumbers and squash cover bare ground after onions. They access deep nutrients while deterring pests.
12. Potatoes
Potatoes remain a suitable onion rotation partner if spaced 3-4 years apart. Their deep roots accumulate leached minerals.
13. Garlic & Leeks
Garlic and leeks resist many onion diseases. But at minimum a 4-year rotation between all alliums is still advised.
14. Cover Crops
Use the post-onion window to sow soil-enhancing cover crops like clover, buckwheat or winter rye.
15. Flowers
Blooming annuals like zinnias, calendula and nasturtiums make onion beds aesthetically pleasing while improving soil health.
This covers a wide range of suitable plant families to follow onions! Combine cool and warm season vegetables to maximize productivity.
When to Plant After Onions
Proper timing ensures garden beds aren’t left empty and vulnerable to weeds after onions are harvested.
In most climates, onions are cleared by midsummer, opening space for warm season crops like tomatoes, peppers, beans, squash, and corn. Transplant or direct sow these immediately after old onions are pulled.
For cool weather crops, start seeds or seedlings 4-6 weeks before your last expected spring frost. This gives broccoli, greens, carrots, and other crops time to establish before onion harvesting opens up room.
Overwintering onions expand your rotation options. Follow summer-harvested bulbing onions with hardy greens and roots for fall harvests. Then plant cover crops to enrich the soil over winter.
Companion Planting With Post-Onion Crops
Certain companions can boost growth and deter pests when rotated after onions.
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Dill, catnip, and chervil help repel pests from carrots, beets, and brassicas after onions.
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Marigolds, nasturtiums, and other flowers provide insect-repelling beauty around tomatoes, broccoli, and melons.
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Quick-growing radishes act as trap crops, luring onion pests away from other vegetables.
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Legumes supply nitrogen “credits” to heavy feeders like corn, brassicas, and potatoes after onions.
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Aromatic herbs like basil mask the lingering “oniony” aroma from beds, confusing pests.
Using synergistic companion combinations maximizes your post-onion rotation sequence.
Supporting Soil Health After Onions
It’s important to rebuild soil health after nutrient-demanding onions. Here are some tips:
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Incorporate several inches of compost before replanting beds to restore organic matter and nutrients.
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Consider cover crops or green manures that enhance soil structure and replenish nitrogen.
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Use organic nitrogen amendments like alfalfa meal if leafy greens show signs of deficiency after onions.
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Mulch crops well to conserve soil moisture and temperature for optimal growth.
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Monitor crop health and respond promptly to any signs of pest or disease issues.
With mindful crop selection and soil care, your beds will be full, vibrant, and healthy even after nutrient-hungry onions. Follow these guidelines for ongoing harvests and soil improvement after clearing your alliums.
Root Crops with Different Nutrient Needs
Carrots and beets do well in soil where onions were grown, benefiting from different nutrient requirements.
A bit of frost doesnt bother these veggies; in fact, it makes them taste sweeter. So, theres no rush to harvest them before the first frost.
- Purple Sprouting Broccoli
- All-the-Year-Long Cauliflower
Although brassicas are heavy feeders, you can grow purple sprouting broccoli and all-the-year-long cauliflower to reap rewards in early spring.
Provide a bit of organic nitrogen-rich fertilizer or composted chicken manure to these crops to help boost their performance.
Suggested Crops for Post-Onion Planting by Zone and Type What to Plant After Onions by Growing Zone
| Zone | Nitrogen-Fixing Crops | Leafy Greens | Root Crops | Overwintering Brassicas | Cold Stratification Scatter Garden | Cover Crops |
|---|---|---|---|---|---|---|
| 1-2 | – | – | – | – | Poppies (annual) | – |
| 3-4 | Peas, Fava Beans | Kale, Chard | Carrots, Beets | – | Echinacea (biennial), Hollyhocks (biennial) | Hairy Vetch |
| 5-6 | Peas, Fava Beans | Lettuce, Bok Choy, Spinach, Kale, Chard | Carrots, Beets | Purple Sprouting Broccoli, All-the-Year-Long Cauliflower | Nigella (annual), Calendula | Hairy Vetch, Winter Rye |
| 7-8 | Peas, Fava Beans | Lettuce, Bok Choy, Spinach, Kale, Chard | Carrots, Beets | Purple Sprouting Broccoli, All-the-Year-Long Cauliflower | Anise Hyssop, Rosemary, Wood Betony | Hairy Vetch, Winter Rye |
| 9-10 | Peas, Fava Beans | Lettuce, Bok Choy, Spinach, Kale, Chard | Carrots, Beets | Purple Sprouting Broccoli, All-the-Year-Long Cauliflower | Lavender, Thyme | Hairy Vetch, Winter Rye |
| 11-12 | Peas, Fava Beans | Lettuce, Bok Choy, Spinach, Kale, Chard | Carrots, Beets | Purple Sprouting Broccoli, All-the-Year-Long Cauliflower | Calendula, Borage | Hairy Vetch, Winter Rye |
Since onions significantly deplete soil nitrogen, consider planting crops that restore this vital nutrient.
Right after harvesting onions, peas are my go-to choice. These nitrogen-fixing plants not only grow quickly but also replenish nitrogen levels in the soil. I have an article that details the process that beans and soil microbes use to create nitrogen nodules – itâs fascinating!
Fava beans are also great for mild winters and will overwinter in zones 7+ for a June harvest.
Picture a mix of vibrant pink radicchio lettuce and the deep blues, greens, and purples of kale leaves, adding a splash of color to your garden and plate.
Lettuce, bok choy, and spinach are perfect plants to follow onions. If you had tried sowing salad greens earlier in the season only for them to bolt, nowâs your opportunity for a second go at it.
Kale and chard are hardy choices that keep growing even with light frosts. Add a fabric row cover and get cut-and-come-again harvests of fresh greens throughout the winter! I am usually able to harvest from this pair until December or beyond!
They have different nutrient needs and dont deplete the soil as much, adding a fresh, vibrant touch to your garden and meals.
Succession Planting | Beans (Legumes) after Garlic and Onions
FAQ
What crop to rotate after onions?
Leafy Greens
Lettuce, bok choy, and spinach are perfect plants to follow onions.
What should not be planted after onions?
Onions, garlic, leeks, and shallots can stunt the growth of plants like pole beans and peas. You also don’t want to plant onions, garlic, leeks, and shallots near each other because if one crop comes down with pests (onion maggots) the rest will also fall victim, like a bad case of head lice.
What to do after planting onions?
Onions roots are shallow and not very efficient at taking up moisture, so they need a steady supply of water to grow without interruption. Although they actually recover well from drought and start growing again when watered, it is best to keep the soil consistently moist until the bulbs enlarge.
What is the best order for crop rotation?
One approach to crop rotation is to divide your plants into these four basic groups: legumes, root crops, fruit crops, and leaf crops. Imagine your garden separated into four areas, as shown in the chart at the top of the page. Each successive year, you would move each group one spot clockwise.