After harvesting the last of my onions, I’m always excited to plan what comes next. There’s 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 I've learned from my own garden.
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 - it’s 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, now’s 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 don't deplete the soil as much, adding a fresh, vibrant touch to your garden and meals.
Carrots and beets do well in soil where onions were grown, benefiting from different nutrient requirements.
A bit of frost doesn't bother these veggies; in fact, it makes them taste sweeter. So, there's no rush to harvest them before the first frost.
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.
If you’re within a week or two of your first frost before heading into a long winter, you can try a bit of chaos gardening with flowers that require a period of cold in order to germinate and thrive.
You’ll essentially be replicating nature - dropping the seeds now, letting winter do its thing, and then you’ll have a bed full of germinating beauties in the spring!
Note that biennials typically won’t bloom until year 2 growing in your garden, BUT plants established early like hollyhocks might give you a year 1 bloom. It’s worth an experiment!
Great options for a late-summer flower scatter garden:
Some herbs that need cold stratification:
For more on cold stratification, I’ve got a full list of flowers, herbs, and veggies that need cold in order to germinate.
Cover crops are key in regenerative gardening. Certain cover crops replenish nitrogen and overwinter, protecting soil from erosion after an onion harvest.
Hairy vetch is a favorite of mine because it combats soil diseases and pests while adding nitrogen. Its purple flowers also attract bees in spring.
If you’re a big fan of mulch (and who isn’t!?), you can grow your own by sowing a crop of winter rye right now.
Compost is my garden’s multivitamin. It enriches the soil, improves its structure, and promotes healthy plant growth. I make sure to add a generous amount before planting.
Once your plants have grown to around 3 inches, mulch around them with weed free grass clippings or organic straw to help keep moisture in during the heat of August and September. Heavier mulch applications in the autumn (perfect timing with fallen leaves!) will help your veggies to last longer beyond your frosts and even overwinter.
When planning your post-onion planting, it’s important to consider your yield goals. To maximize yield, choose crops that thrive in the nutrient conditions left by onions and grow quickly for a bountiful harvest. Nitrogen-fixing crops like peas and fava beans are excellent for improving soil health and setting the stage for high-yield plants in the following season. Leafy greens such as lettuce, bok choy, and spinach can offer multiple harvests, especially if grown using cut-and-come-again methods. Additionally, overwintering crops like purple sprouting broccoli can provide valuable harvests during the early spring hunger gap, ensuring a continuous supply of fresh produce.
Different gardening styles can influence what you might choose to plant after onions.
For organic gardeners, legumes like peas and fava beans are excellent choices because they improve soil fertility naturally without synthetic fertilizers.
In permaculture gardens, incorporating a variety of crops to create a polyculture can enhance biodiversity and resilience. For example, interplanting leafy greens and root vegetables with nitrogen-fixers can create a balanced ecosystem that supports each plant’s growth and the overall health of the garden.
Traditional row gardening might focus more on sequential planting, ensuring that each crop benefits from the previous one’s soil improvements.
Gardening is a journey of learning and experimenting. By thoughtfully planning what to plant after onions, you’ll not only enjoy a longer period of garden-fresh food, but also contribute to a thriving garden ecosystem. Now go on and check that your onions are curing properly so you can mix those into meals with your fall harvests.
