Onion Growing and Harvesting Tips: Transitioning from Summer to Fall

Fellow green thumbs! Today, I want to share some handy tips on growing and harvesting onions with you, especially as we transition from the hot days of summer into the cooler vibes of fall. Whether you’re a novice or just looking to sharpen your garden game, onions are surprisingly rewarding and pretty straightforward to grow. Let’s dive right in!

A Fall Garden Favorite

Onions are one of the versatile veggies that thrive once you get your timing right. Plant them in late summer or early fall to develop strong roots before winter sets in, and they’ll be ready to burst into action come spring. Pulling up your onions for the kitchen from the garden is truly satisfying—whether it’s for hearty soups or salads.

Choosing Your Variety

There are three main types of onions you’ll want to consider planting:

Short-day onions: Best for southern regions; they start forming bulbs when daylight is about 10-12 hours.

Long-day onions: Ideal for northern climates; they bulb when daylight hits 14-16 hours.

Day-neutral onions: A bit of a mix, these typically grow well anywhere.

I always recommend checking your local seed catalog to see which variety suits your area. For example, long-day onions like Walla Walla were my go-to when I lived in the Pacific Northwest—sweet and perfect for the climate.

Planting Tips for Onions

Start with healthy seedlings: I usually buy onion sets (small bulbs) because they’re easy to handle and get a head start. But if you want to grow from seeds, start indoors early.

Soil prep is key: Onions prefer well-draining soil rich in organic matter. Before planting, work in some compost or aged manure. Give each onion about 4-6 inches of breathing room. Overcrowding leads to smaller bulbs.

Water consistently and add mulch: Onions need steady moisture, especially as they bulge. But avoid overwatering as soggy soil can rot your bulbs. Adding mulch helps retain moisture and keeps weeds at bay.

Onions and the Moon

Here’s a quirky tip from veteran gardeners: some swear by planting onions during a waning moon for better bulb development. While I can’t scientifically vouch for this method, my onions did seem extra plump that year when I gave it a try. 

Harvesting Your Onions

Knowing when to harvest is crucial. When green tops start yellowing and falling over, your onions are telling you they’re ready.

After pulling them, lay your onions in a warm, dry, and airy spot for one to two weeks. This hardens the skin and ensures they store well. Remember to use damaged bulbs first: onions with spots or soft skins should be consumed quickly.

Summer to Fall

As summer winds down, your garden’s energy shifts too. This is a great time to plant cool-season crops. Alongside onions, think lettuce, spinach, kale, and root veggies like carrots.

Clear out spent summer plants, add fresh compost, and mulch heavily to protect soil from cooling too fast. Autumn is the ideal time for soil building. Top dress beds with compost or sow cover crops to boost growth over winter. 

Cooler temperatures also mean less evaporation, so adjust watering schedules to avoid overwatering. As fall approaches, some pests slow down, but others, like slugs, love fall’s dampness, so pay attention to your plants. 

Wrapping Up

Growing onions is a rewarding experience that complements the rhythm of changing seasons. With patience and effort, you’ll have a bountiful harvest to enjoy all winter long, setting you up for success for next spring.