As gardeners we often worry about how cold it can get before our plants start to suffer, but there are many species out there that are just as sensitive to weather that is too warm. Tulips are one such plant.
If it doesn’t get cool enough for long enough in your area, your tulips won’t bloom.
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Ready to throw up your hands in defeat and give up your dreams of a field full of tulips?
It’s actually possible to trick your plants into thinking that they’re living in the sort of climate they prefer if your neck of the woods is too warm.
If you live in a warm climate and your tulips have struggled or even failed, this guide aims to set you back on the path toward success.
Coming up, here’s what we’ll discuss:
What You’ll Learn
Anyone in USDA Hardiness Zones 8 to 10 will definitely have to chill their tulips.
You might even need to chill them in Zone 7, depending on where you plant them.
For example, if you plant your tulips next to a brick or cement wall, the reflected heat will be too much for the plants, and they’ll require chilling to rebloom.
How Cold Should Temperatures Be?
When winter rolls around and most plants go dormant, tulip bulbs are busy prepping for the coming year. The bulbs go dormant early, in the summer rather than the winter.
During the cold period of wintertime weather, the bulbs start to convert the starches and other carbohydrates that they collected and stored during the growing season into sugar in the form of glucose.
Not only does this glucose protect the bulb from freezing, but it supplies the nutrients the bulb needs to send out roots, flowers, and leaves in the spring.
The soil surrounding the tulips must drop below 55°F for all this to happen.
There isn’t an exact time period required for the bulbs to develop enough glucose to thrive, but somewhere between 12 and 14 weeks seems to do the trick.
Anything less than 12 weeks is probably too short.
Tulips require this period of cold weather because they evolved in regions of central and southwest Asia that experience extended cold winters.
Tricking the Bulbs
If you live somewhere where you can’t count on the soil temperature to drop and stay below 55°F for at least 12 weeks, you can place the bulbs somewhere cool enough to trigger the process artificially.
A refrigerator is the perfect spot.
You need to start this process about 12 weeks before the midpoint of winter.
Lots of people make the mistake of starting just as spring begins, but that would mean you’ll be putting the bulbs outside when the weather is still too warm.
This will cause premature sprouting and could kill the beginnings of the flowers developing inside.
Don’t start chilling until after December 1st at the earliest.
And don’t just toss a bunch of tulip bulbs into a bag and stuff it in the back of the fridge. This is a recipe for rot. Instead, use an old cardboard egg carton and place one bulb in each section. You could also use a mesh or paper bag to facilitate proper airflow.
Keep the bulbs far away from veggies and fruit. Types of produce like apples put out a lot of ethylene, and this gas can trigger premature growth.
After at least 12 weeks have passed, remove the bulbs from the fridge and inspect them for any soft spots or signs of rot. Plant the healthy ones in the ground at about six inches deep.
The ground might be frozen in your area at this time, and that’s okay. You’ll just have to break out the chisel or put your back into it with a shovel. Holes can be pre-dug earlier in the year as well.
You don’t want the bulbs to warm back up until they normally would in the spring, so don’t remove them from the fridge, get distracted, and leave them on your counter for a few days. Planting should be done right away.
How to Grow
Once planted in the ground, you can generally forget about them until the leaves start to emerge in the spring.
There is one exception to this: If you have an extended warm period with temperatures above 55°F for several weeks on the horizon, you’ll need to dig the tulip bulbs back up, put them in some potting soil in pots, and stick them back in the fridge.
The plant needs cool weather while they’re in the soil in late winter and early spring to develop strong roots. If it gets too warm, they won’t be able to develop, or they will be weak.
That said, there is a way to get around digging up the bulbs during a warm stretch.
If the daytime high temperature is hovering right around 60°F and not warmer, you can usually get away with covering the soil with a few inches of mulch rather than moving them to pots in the fridge.
If it’s dry in your neck of the woods during the winter, make sure to keep the soil moist but not wet.
The bad news about this method is that you’ll have to dig up the tulip bulbs every year and repeat the process, or just expect them to grow as annuals that must be replaced.
If you want to dig the bulbs up and regrow them, you’ll need to wait for the flowers and leaves to fade. Then, dig the bulbs up and store them in a cool, dark place in a refrigerator or cold cellar.
Then, give them another 12 weeks in the fridge starting at the appropriate time in late fall.
Even if you go through all this work, there’s no guarantee that your plants will bloom the second year. Artificially cooled bulbs just sometimes don’t work.
By the way, if you want to skip the digging up and replanting process, you can keep the bulbs in the pot that you chill them in.
Move the pot outdoors when you would typically plant and bring them back in after the leaves fade. They can regrow this way for years.
Pre-Chilled Tulip Bulbs
You can also purchase bulbs that have been chilled for you. These are an excellent option if you missed the cooling period, but you still want to be able to enjoy tulips in your warm-climate garden.
These must be planted immediately after you receive them. As with those that you chill yourself, you can’t allow them to warm up before planting.
Best Hybrids and Species to Select
Want to skip a few steps? There are actually a few tulips that manage just fine in Zone 8, or even 9.
‘Little Beauty’ is a hybrid that will bloom even if you don’t chill it. Tulipa clusiana, or lady tulip, cultivars also do well without a chill.
The following options do require a chill, but they do extremely well when grown this way and might even give you a second year of flowers even if you don’t dig them up and chill them again in advance of the next year.
‘Makeup’ has pure white petals edged in red. ‘Hocus Pocus’ has magical yellow blossoms with pink tips.
‘Queen of the Night’ has nearly black, purplish petals atop 22-inch stems. This option is available at Eden Brothers in quantities of 10, 20, 50, and 100.
Striking ‘Apeldoorn’ features pinkish-red petals edged in apricot.
‘Pink Impression’ is, unsurprisingly, pink, and ‘White Triumphator’ is white. For lemon yellow flowers edged in red, grab ‘Akebono.’
Most Darwin hybrids are adaptable to warmer climates, too.
Or have someone else do the work for you and grab ‘Pink Passion’ pre-chilled bulbs in a pretty pink hue at Walmart.
Some Don’t Like It Hot
Like all plants, tulips evolved to thrive in certain climate conditions, and they simply won’t be happy in anything else.
But if you can trick them into thinking they’re in the type of environment they prefer, you can enjoy these classic flowers even outside of their normal temperature range.
Now that you have the keys to warm weather Tulipa growing, what types will you feature in your garden? What area do you live in?
Share the details in the comments to give your fellow gardeners some ideas that might also work for them.
And if you’d like to learn more about growing fascinating and colorful tulips at home, check out these guides next:
