Should You Refrigerate Fall Bulbs Before Planting?

Fall bulbs are hardy little perennials that thrive without much care. They’re perfect for neglected borders, perennial plantings, and containers, as they go dormant half the year and sprout under warm temperatures. Fall species also go by “hardy bulbs” since they’re more frost tolerant than tender ones like gladiolus, dahlias, and calla lilies. 

This frost tolerance isn’t just a defense mechanism; it’s a method they use to rest and recuperate from the growing season. Cool fall and winter temperatures signal these plants that it’s time to take a break from growing flowers and leaves. They’ll start conserving energy in their bulbous roots, which swell and divide during the cool months.

If you don’t have cold winters, you might wonder if your bulbs need to be refrigerated before fall planting. They may require it depending on your growing zone, its average winter temperatures, and the species you’re planting. We’ll discuss all of these variables and how they affect hardy bulbs. Let’s dive deep below ground to see what these perennials do and how they survive!

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The Short Answer

You should refrigerate hardy bulbs before planting in the fall or winter if you live in a warm climate. Species like tulips daffodils, and crocuses require frigid winter temperatures so they can rest properly. Without cold, they won’t survive well year to year and will eventually die out.

You don’t have to refrigerate them if you live in a cool climate zone where bulbs naturalize outdoors. Some areas, like the Pacific Northwest, are perfect for this. They have spring rain, summer warmth, and winter cold. Simulate these three conditions outside of cool zones, and you’ll successfully grow fall-bulbing species year after year.

The Long Answer

Whether or not you should refrigerate hardy bulbs depends on a few factors. Let’s break down each one to see how they affect your decision. By the end of this guide, you’ll know exactly which ones to refrigerate and which to plant in the ground.

Hardy vs. Tender Bulbs

Fall bulbs are hardy ones that thrive under frigid winter weather. You can put them in the fridge before planting if your winters are relatively mild. Tender ones are different—they’ll die if you put them in your fridge! They grow in areas without significant winter frosts and prefer warm temperatures year-round.

Tender bulbs need different care than hardy ones. They are only perennial in warm winter zones without frosts. You’ll have to store them indoors in a warm location if you have frigid winters. Many gardeners do this with dahlias to preserve their favorite varieties. 

Hardy bulbous plants prefer the opposite type of care! They need warm growing seasons and cold dormant ones. This means they’ll tolerate refrigeration during the winter if your ecoregion lacks freezes or frosts.

Trick Fall Bulbs In Warm Climates

Refrigeration is a boon to hardy bulbous perennials if your winters are warm, above 50°F (10°C) on average. Your warm outdoor weather confuses them into sprouting prematurely before they put down sufficient roots. They’ll struggle to enter dormancy unless you trick them with a few weeks or months in your refrigerator.

If you bought bulbs this fall and live in USDA hardiness zones 10 or above, you’ll want to refrigerate them for three to four months before planting. The goal is to convince the plants to think they’re underground during frigid, freezing weather. 

To store bulbs in the refrigerator, start by preparing a box, bag, or container. Poke holes so air can flow in and out of the container. Then, place them inside with a medium like sawdust, vermiculite, or straw. Cover them but leave their tops exposed so they have access to air. You may see some root growth if the container is clear! It’s normal, as hardy species use cool temperatures to root into the soil.

One note is to avoid placing them near ripening apples or other fruits that give off lots of ethylene. Ethylene is a natural gas that forms as the fruit ripens, and it encourages other plants to flower, fruit, or grow abnormally. Keep your planting material far away from these fruits to protect them and prevent rot, disease, or late sprouting.

Cold Climate Care

Cold zones 3 through 9 have ideal temperatures for growing plants like daffodils and tulips outdoors. You can plant them in during autumn they’ll thrive below ground despite freezing weather and rainy storms. They appreciate some time before a hard frost to sprout roots underground. 

Aim to plant them six to eight weeks before your first hard frost. This gives these perennials ample time to sprout roots and grow hardy below ground. They’ll thrive best in a site with free draining and fertile soil. Two things threaten them outdoors: standing water and sharp rocks or gravel.

If the site has standing water, amend it months before planting with compost or organic mulch. Dig these amendments in to encourage worms and microbes to colonize the soil—they’ll turn clay into rich, crumbly humus with time. If there are rocks or gravel, simply remove them before planting. Compost is beneficial for them year-round, but especially so during winter. Add a thick layer to the soil above bulbing species in cold zones 3 and 4 to protect them from heaving and hard frosts.

What Happens If It’s Too Late?

Let’s say it’s late spring, and you forgot refrigerate your fall bulbs—what should you do? It’s best to plant them now instead of waiting for next fall. They’ll survive 12 months or less in the refrigerator and may start rotting if they stay in there too long. They need access to sunlight and moisture to break dormancy. 

The bulbs may perform oddly by flowering late in the season or not at all. If you live in a cold zone, let them sprout, and they’ll adapt to nature’s seasons by next spring. Most species will flower after they have a winter season underground. If you live in a warm winter zone, let the plants sprout throughout the summer and prepare to refrigerate them again in the fall or winter.

Spring Care

After a winter period below ground or in your fridge, bulbing ornamental species are ready to flower and thrive above ground. They’ll want to soak up excess warmth and sunshine as they become more available in spring. The type of spring care to give them depends on whether your plants live outdoors or in the fridge for the winter.

Outdoor specimens need little care—ensure they don’t have soggy soil, but keep it consistently moist as they sprout. Most species need full sun or partial shade. Tulips, daffodils, snowdrops, and crocuses sprout before deciduous trees open their leaves, meaning you can plant them below the bare canopy and they’ll go dormant before the site grows too shady. If you added thick layers of mulch to protect your bulbs from hard frosts, move it aside to let new leaves and buds come up.

Bulbs from the refrigerator need to adapt to outdoor conditions. Plant them anytime in winter or early spring after three to four months in the fridge. Avoid planting them after January in warm zones, as it’s often too warm for them to perform well. 

After plants flower, they start forming seeds or seed pods to propagate. Let them go to seed if you’d like to collect it—otherwise, cut spent flowers off before they form seeds. Cutting the flowers off encourages the plants to preserve their energy, leading to more flowers next year and a bigger bulb. 

Refrigerate Bulbs Annually In Warm Zones

For easy growing, use tender bulbs in warm or tropical climates and hardy ones in temperate areas. If you try to swap them, you’ll have a little extra work to do to trick them into growing with your seasons. I love begonias, so I do a bit of work to preserve them in my Pacific Northwest garden. If you’re like me and have a favorite plant that doesn’t grow well without help, fear not! There are storage solutions.

Hardy species need refrigeration annually in warm zones. You’ll want to dig them up in early fall after they go dormant and prepare them for cold storage. Use the methods mentioned above for tricking fall bulbs in warm climates, and bring them outside once spring arrives.

Before storing your plants, let them dry so they’re crispy. They should have a thin papery layer, like onions, protecting their fleshy inner parts. Ensure no sprouts or stems are elongating, and cut off old growth. You’ll want them to be dry, dormant, and free from dying plant parts for optimal winter survival rates.

Leave Bulbs Underground In Cold Zones

Cold climate gardeners in zones 9 and below are lucky! You can plant these perennial species in the ground and forget about them for years. They’ll sprout and go dormant with little interference, providing annual blooms for pollinators to enjoy. 

After three or four years, bulbing species may need dividing and replanting. They’ll grow crowded over time, sprouting new corms, rhizomes, or bulbs in their root zone. Crowded roots cause weak flowers or none at all, as stressed plants struggle to perform. 

Remedy crowded plants by digging them up after their leaves yellow and wither. Separate them from each other, and bury them as deep as they need in new sites. Each bulb will sprout into more, which means you’ll keep multiplying your plants every time you divide them. Plant daffodils today, and you’ll have more than you can deal with in a few years!

If your bulbous perennials are performing well without issue, leave them be. Only dig and divide them if you notice signs of disease, no flowers, or many pests.