Have you ever forced bulbs so that you have indoor pots of color when it’s still awful out in later winter and early spring? It’s really easy.
To get started, I ordered a mix of crocuses, old-fashioned jonquils, tulips and a couple of large Narcissus varieties. (Typically, I got carried away and ordered way too much.) Then I dumped out what was left of summer and fall annuals and washed out the pots.
Here’s a look, as I got started.
You want to really cram in the bulbs. First add a couple of inches of ordinary potting soil, then lay the bulbs on top. Here’s a pot of crocuses. (The pointy end of the bulb always faces up.)
Then cover with the same potting soil.
You just need to water the pot once, then stick it in a plastic shopping bag and loosely twist-tie the top closed. Then move the pot into cold storage for 12 to 17 weeks, depending on the bulb. I’ve got an unheated basement, which is perfect. It stays below 50 degrees, but never goes below freezing.
Here’s a pot of daffodil bulbs, ready for more soil, then water, then a few weeks of cold.
And a mix of tulips that the folks at the Netherlands Flower Information Center sent to me to try. (I planted the rest in the yard.)
Want to learn more about how to force bulbs? Here’s a story I did for the paper a few Decembers ago:
“Now that paperwhites and amaryllis bulbs are on display at florists, nurseries and home centers, the holiday shopping season must be heading into high gear. What could be easier than planting these holiday favorites in a bit of soil or gravel – or even just a vase of water – and then waiting a few weeks for a burst of color and scent? Perfect as a centerpiece on the holiday buffet table or as a gift for a hostess, neighbor or teacher.
“But you really don’t have to limit yourself to amaryllis and paperwhites, which are great for beginners because the bulbs are from the tropics and don’t need a cold period to set their flowers.
This year, why not try some other bulbs, such as tulips, daffodils or crocuses? Almost any bulb can be “forced,” or tricked into blooming earlier than it would if left to its own devices, buried somewhere out there below the cold, gray lawn. Start the process now and you’ll be rewarded with wonderful pots of indoor color in February and March, when most gardeners are mad for spring.
“Bulbs are a complete package,” says Sarah Price, who led a recent workshop on forcing bulbs at Montgomery Place, a historic Hudson River estate in Annandale-on-Hudson, where she is the landscape manager. “They’re ready to go – if you treat them properly, you can’t go wrong.”
Bulbs fall into two categories: ones that don’t need a cold period to bloom (paperwhites and amaryllis) and ones that do need several weeks of cold in order to bloom (all the rest).
“The trickiest thing about forcing bulbs is finding a cool place for them,” Price says.
An unheated basement or garage should work, or many homeowners have a spare refrigerator in the garage or even outdoor cold frames. Price recommends putting the potted-up bulbs into a tied-up plastic bag and then into a refrigerator. The plastic will keep them moist and protect them from any fruit, such as apples, that releases ethylene gas.
Experts recommend a temperature between 41 and 48 degrees, but anywhere between 35 and 55 degrees should work, Price says. Just make sure the bulbs don’t freeze.
(If you don’t want to bother with this process, some home centers and mail-order companies offer “hardened-off” bulbs that have already been through the cold period and are ready to go.)
Some of the companies, such as Brent and Becky’s Bulbs in Gloucester, Va., also indicate which of their bulbs make particularly good forcers.
“In most cases, you want ones that have smaller flowers,” Price says, “not a big blousy King Alfred daffodil, for example.”
For tulips, look for early bloomers with short stems, she says, and avoid the Darwin varieties.
Sally Ferguson, director of the Netherlands Flower Bulb Information Center in Brooklyn, has two favorites among the tulip cultivars: `Monte Carlo,’ an early bloomer with double flowers and a honey scent, and `Angelique,’ also a double flower but with a later bloom.
“They’re fast bloomers with sturdy stems and blooms that last a long time,” Ferguson says.
In her recent workshop, Price used two kinds of bulbs that she had ordered from Brent and Becky’s: grape hyacinths or muscari and a daffodil cultivar called `Hillstar.’
” `Hillstar’ has two to three flowers per stem, which is good, and it’s 14 to 16 inches tall, a nice height in a pot,” Price says.
If you order bulbs by mail, open the box immediately and check for soft or rotten ones. Get rid of those right away, and take the rest out of the box so that they can breathe.
You can pot them up at once or you can wait a bit and try to time their bloom by looking at a calendar and counting backward by the number of weeks needed in cold storage.
Let’s say you want blooming daffodils, which need about 15 weeks of cold, for a party on April 1. Count back 15 weeks to Dec. 18, then allow another two weeks for them to grow and bloom. That means you should pot them and start the cold storage on Dec. 3.
To begin, all you need is good-quality potting soil and a container with a drainage hole. “It can be anything – plastic, clay, glass, even an old shoe,” Price says.
Cover the drainage hole with newspaper or a broken pot shard and add about 2 inches of potting soil.
Cram as many bulbs as you can into the pot, Price advises. Forget all the rules about spacing that apply for outdoor planting.
“Forcing bulbs is all about show,” she says. “You want it to look lush; you want it to look full.”
Once the bulbs are in the pot, cover them with dirt and water once. Put the container into a plastic bag and move it to cold storage for the recommended number of weeks. Check occasionally to make sure they’ve stayed relatively dry.
When you bring the bulbs out of storage, put the container in a bright window and begin to water them again. After two to three weeks, they’ll begin to sprout and show color. Then move them to a spot with indirect sunlight.
Forcing bulbs indoors is also a great way to use up any extras that you never got around to planting earlier in the fall. Then you can plant them in the garden next spring after they’ve bloomed indoors and you’ll be rewarded with outdoor blooms for years to come (although they probably won’t flower the first year outdoors).
And don’t forget to label each pot of bulbs because you probably won’t remember what you planted by the time the bulbs begin to bloom.
Bulbs 101
No cold period required
Amaryllis: will bloom 6 to 8 weeks after potting
Paperwhite narcissus: will bloom 3 to 5 weeks after potting
Bulbs needing a cold period
The ideal temperature for forcing bulbs is between 41 and 48 degrees, but anywhere between 35 and 55 degrees should work. Don’t go below freezing, though. Check instructions that come with the bulbs for exact weeks of cold, but here are general guidelines:
Large-flowered
Daffodil (15 to 17 weeks of cold)
Hyacinth (11 to 14 weeks)
Tulip (14 to 20 weeks)
Small-flowered
Crocus (15 weeks)
Dwarf iris (Iris danfordiae and Iris reticulata) (15 weeks)
Grape hyacinth or muscari (13 to 15 weeks)
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Bill Cary grew up in Louisville, Ky. His gardening was limited to growing parsley and impatiens on the windowsill of Manhattan walkups until the mid-1990s when he bought a rundown old chicken farm on 8 acres in the Hudson Valley. Now he spends his weekends chasing deer, hacking away at invasive shrubs and vines and wondering why he doesn`t have more meadow and less lawn.
