Forcing Bulbs Indoors For Winter Blooms: How-To & Tips

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Imagine the dreary months of January and February, cold, bleak, windy–but you can easily add a touch of Spring inside your home by forcing bulbs ahead of time that will then bloom indoors during the winter months. Here’s how…

Understanding How It Works:

Potted Hyacinth Bulbs

Flowering bulbs like Tulips need to be planted in the Fall so that they can experience being cold and a period of dormancy during the winter season. Once it begins to warm, they know Spring is near and start growing their shoots to the top of the soil that will then produce their blooms.

Many won’t grow and bloom until they first experience this chilling period. Forcing has to accomplish this same experience:

• Give them a “season” of cold so that they think Winter has arrived.
• After a few months of being chilled, bring them inside the house to experience the “season” of warmth–they’ll think Spring has arrived and will begin to grow and bloom.

Here’s How To Do It:

• Choose well draining pots so that the bulbs won’t rot and they can be transported easily inside the house to a warm, sunny location.
• Cover the bottom of the pot with gravel to support good drainage then top up with potting soil.
• Position as many bulbs as you’d like on top of the potting soil with their pointy sides up and the root growing side down. There’s no need to space them as you would when planting in a garden, just make sure that no two are touching each other or the sides of the pot.
• Then cover them with some potting soil leaving the top tips exposed.
• Water the pot thoroughly then allow to drain.
• Place in a cold, dark location like an unheated garage or garden shed–somewhere that gets cold but doesn’t drop below freezing (the rooting process will stop if the bulbs freeze). If you have room to spare in an old refrigerator, you can force them in there too (ideal but watch the soil moisture, will likely need to water regularly). You can also dig a trench outdoors to hold all your pots until it’s time to bring them in. Dig the trench about 2 feet deep and as wide as you need to hold the pots. Cover with a good layer of straw and leaves to give them some protection from the cold (about a foot deep in harsh winters).
• If positioned somewhere inside, water occasionally with cold water so that the soil doesn’t dry out completely, don’t give too much water though, just sparingly. If the pots were left outdoors, watering once a month should be sufficient (if it’s a dry winter).
• Let them chill for about 13 to 15 weeks. When they’re ready to be moved indoors, you will see roots in the drainage holes at the bottom of the pots or new stem growth at the top that’s about two inches high.
• When it’s time to bring them inside, transition them first by putting them in the coolest room you have (with some light). Water thoroughly once you bring them in. After a few days you should notice some new plant growth, once you do you can move them to a warmer and sunnier location inside the home.
• For the next two to three weeks you’ll notice the shoots growing and then starting to bloom.

Varieties That Work:

Hyacinth Growing And Blooming In A Pot

• Tulips: Can require at least 15 weeks of chilling to be successful. Early flowering tulips are easier to force, some suggestions: Beauty of Apeldoorn, Apricot Beauty, Monte Carlo, Oxford, Mariette, Aladdin, Maytime, Diana, Brilliant Star.
• Hyacinths: Wait until the top growth is about 3″ before moving to a sunny location. Usually requires at least 10 weeks of chilling to be successful. Varieties to try: Pink Pearl, Delft Blue, Anne marie, Carnegie, Hollyhock, Amethyst.
• Daffodils: Usually requires at least 13 weeks of chilling to be successful. Varieties to try: Carlton, Cheerfulness, Flower Drift, Ice Follies, February Gold, Fortune, Dutch Master, Easter Joy, Geranium, Golden Bells, Jetfire. Place in direct sunlight to help it bloom properly after being forced.
• Crocus: Can require up to 15 weeks of chilling to be successful. Some varieties to try: Remembrance, Giant Yellow, Jeanne d’Arc, Peter Pan, Flower Record, Pickwick.
• Iris: Can require up to 15 weeks of chilling to be successful. Dwarf Irises force well.
• Paperwhite Narcissus: See details below.

Tips:

• Time the blooms for special events such as Christmas, Valentine’s Day, New Years, etc. Plant in pots approximately 15 to 17 weeks before you want the blooms.
• The bulbs won’t likely force successfully again next year, but plant them in the garden in the Spring once they’re done blooming and have died back–they may give blooms after a year or two in the garden.
• The best time to purchase bulbs for forcing is in the Fall, you’ll likely not find a good selection during the winter.
• Stagger the bloom times by planting and bringing out each pot about a week apart from each other.

Paperwhite Narcissus

*First published October 12, 2009 and moved to this page for better organization

Paper white narcissus (daffodil family) is one of the easiest to force indoors over the winter season and they don’t need to be chilled first like others do. Here’s how you do it:

Paperwhites Can Add A Beautiful Touch Of Spring Over The Cold Winter Months

• Choose a container that’s at least 2 inches deep and will be large enough to hold the amount you wish to plant. Fill the container with a layer of pebbles or glass marbles leaving a space of at least one inch at the top of container.
• Arrange each bulb on top of the pebbles with the root side down then cover with more pebbles until they are secured in place (covered about 1/3 of the way up the bulbs). No need to worry about spacing with this method, fill the container with as many as you like without letting them touch each other.
• Next, fill the container with water until the level reaches just beneath the bottom of the bulbs. You don’t want them submerged in water as this will cause them to rot. By having the water very close to the bulbs, the root growth will be drawn down into the water.
• Encourage strong root development by placing the container in a cool dark place for about 2 weeks. You should also notice new plant growth at least an inch or two tall. After two weeks move the container to a bright location.
• Make sure to watch the water level, keeping it just underneath the bulbs at all times.
• They will begin to bloom between 4 and 6 weeks and should last about 2 weeks. Once they have faded, they will not be able to rebloom.

Tip: For pots of continuous blooms, prepare a new pot every 10 days or so.