Forcing Bulbs

Forcing Bulbs

Part of Ep. 903 Fall is for Planting and Picking

Force bulbs such as tulips and daffodils to bloom in the dead of winter.  Karen Johannsen from Johannsen's Greenhouse in Madison shares her secrets. Topics include bulbs, pots, the ideal storage temperature and which bulbs can be transplanted into the ground.

Premiere date: Oct 03, 2001

TRANSCRIPT+
Wisc Gardener Transcript: 

Shelley:
Imagine it's the dead of winter outside. It's cold, dark and dreary. A pot of beautiful, colorful blooming bulbs would be perfect right now, wouldn't they? They're easy to do. All you have to do is plan ahead. This is Karen Johannsen. And we're at Johannsen's Greenhouse in Madison. Karen, why do we have to plan ahead, now in the Fall, to have blooming bulbs next January or February?

Karen:
Well, you have to do a process that's called "forcing." And you actually are imitating what happens in the wintertime.

Shelley:
Without running around in the snow, I hope.

Karen:
Exactly. So, what you do is you select your bulbs. You plant them up, you water them in, and then you have to cool them for about 12 weeks. You've got to put them in the refrigerator. Then, you pull them out, put them in a sunny window, watering all the time when they're dry, and then they bloom.

Shelley:
They think winter's come and gone and the sun has come up. Let's start out with bulb selection. What kind of bulbs will we have really great success with?

Karen:
The things that are fun to force are tulips, daffodils, crocus. I especially like these Tete a Tete daffodils. They're short, they're miniature. They only grow about eight inches tall, so they make a really cute little show.

Shelley:
So, is height significant in selecting our bulbs?

Karen:
Yeah, when I select tulips, they usually will grow anywhere from 12 to 24 inches. And generally, I like to take the shorter ones, because they don't flop over in the pots. They work a little bit better.

Shelley:
So, stick to the short. Anything else, as far as selecting bulbs?

Karen:
When you're selecting, size is very important. Like these bargain tulip bulbs compared to the very large tulips. Generally, in bulbs, the larger the bulb, the larger the flower head. And you're going to so much work and time and trouble to get them to bloom, you want the largest flower possible.

Shelley:
Sure, we're not planting these outside by the hundreds, so pick the best you can find, and the largest.

Karen:
Right.

Shelley:
So, we've picked our bulbs. Then what do we do?

Karen:
You want to select a pot that has drainage in it. You want a hole in the bottom. Most people use a clay pot, but any pot will do. Then you fill it up with soil. And we're not using mud from outside, we're using a nice potting mix. So, this one has perlite, peat moss, vermiculite and finally, shredded bark, and it drains real well.

Shelley:
So, these are the sterile, soil-less potting mixes.

Karen:
Right, exactly. Fill your pot up with your soil mix. And then, you go ahead and plant your bulbs in, generally about halfway is how deep you put them.

Shelley:
They also look crowded. Is that correct?

Karen:
Yeah, I like to put them as close together as possible, without touching each other, or without touching the sides of the pot. It just makes a lot prettier show. And you can also mix your kinds of bulbs. This has Tete a Tete daffodils, along with short-species crocus in the front.

Shelley:
What do you have in here?

Karen:
These are Golden Emperor tulips.

Shelley:
These are going to look gorgeous. Okay, we've got them planted.

Karen:
After you plant them in, you want to water them. Then you start your cooling process. You want to put them in the refrigerator at about 40-50 degrees.

Shelley:
What if, since somebody in my family objects to having pots of soil in my refrigerator. Are there other options?

Karen:
You can certainly force them outside in cold frames or an unheated garage, but you do have to pay a lot closer attention to the temperature. If we get some really cold temperatures, you may need to bring them in for a night or two. If they freeze and thaw and freeze and thaw, then they can sometimes rot.

Shelley:
So, too warm is a problem, too. You don't want those extremes at either end.

Karen:
Exactly, 40-50 degrees is what you're looking for.

Shelley:
Okay, we pay attention to temperature. Do we have to worry about watering?

Karen:
I would check them every couple of weeks. When the soil is dry, go ahead and water, because they're still growing. What they're doing in that temperature, is they're forming their root system.

Shelley:
So, they're getting established.

Karen:
Yes.

Shelley:
So, now it's ten to 12 weeks later, and they're done with their chilling treatment. I take them out of the refrigerator, and then what?

Karen:
Put them in the sunniest window that you have. Don't be alarmed. You're going to see sprouts and they're going to be a very pale, sickly looking green.

Shelley:
Because they were in the dark.

Karen:
Exactly. So, put them in a sunny window. They'll green up quite quickly. And then, water as necessary. They're growing a lot more now and it's warmer. So, as the soil is dry, go ahead and water them.

Shelley:
Keep it moist, not soggy.

Karen:
Right, dry in between. And in about two to four weeks, you'll have beautiful flowers.

Shelley:
These are going to look great. A lot of times, I hear people ask, "Can we plant them outside when they're done blooming?"

Karen:
You certainly can, but forcing takes a lot of energy out of the bulb. if you want to try to plant them again, you want to cut the flower heads off as soon as they've faded. But then, you have to allow the green to continue growing, because it has to put energy in for next year's bloom. And as soon as you can get out and work in the garden in the spring, go ahead and plant them in. Keep your fingers crossed. They may not bloom the next fall, but the fall after, hopefully they'll bloom again for you.

Shelley:
And I would assume, make sure that they're the hardy bulbs that we're planting outside.

Karen:
Yes.

Shelley:
Not Paper Whites, but tulips, crocus or daffodils.

Karen:
Right.

Shelley:
Thanks, Karen. Imagine how these are going to look on a cold, dark January. If you don't have room in the refrigerator, or maybe, you're just new at forcing bulbs, try forcing hyacinth bulbs. They're easy and almost fool proof. Simply put them in a paper bag in the refrigerator for four to six weeks. Then, bring them out and they're ready to go. Forcing jars produce the best results, allowing light in and room for the roots to grow. Forcing jars are inexpensive and readily available at nursery and craft stores. Feel free to experiment with other containers. Fill them with water, put in the bulbs and place them in a bright window. The roots should always be in water. In about four weeks, you'll have beautiful, scented hyacinth flowers. These bulbs are heirloom varieties, available from Seed Savers Exchange and Old House Gardens. Like other forced bulbs, these can be planted outside in spring, but expect them to spend at least one season recovering. This is a great way to have blooming flowers, and a wonderful scent indoors all winter long.

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