Forcing Spring Bulbs Indoors Getting Your Garden Started

Forcing Spring Bulbs Indoors

Forcing Spring Bulbs IndoorsForcing spring bulbs indoors in the height of winter sounds uncooperative and manipulative. However, bulbs are not coerced; they are merely responding to their natural seasonal growth pattern. If there is any forcing or manipulation, it is with temperature and light to mock the seasonal requirements for root growth in winter and above ground stem, leaf and blossoms in the spring. The reason for forcing spring bulbs indoors is to enjoy their beauty during the cold months of winter. In geographic locations like California and some southern states, there isn’t the cold soil temperatures in winter for root development and the bulbs will not flower.


Normal Life-Cycle of Bulbs

During the cooler temperature, rainwater, and light snow of fall, the bulbs develop new roots. The moist soil sends root growth down into the dirt, reviving the dormant bulb through the cold winter months. When winter ends, the warmth and sunlight of spring trigger the above ground growth of stem, leaves, buds, and flowers. As spring turns to summer, the flowers and leaves dry up, and the bulb pulls nutrients back into the bulb, getting ready to return to a dormant state.


How to Force Spring Bulbs Indoors

In early fall, pot the largest, healthiest looking bulbs. A wide, shallow, clay pot for good drainage works best – four to six inches deep. The pot depth for daffodils is the exception, requiring a deeper pot. Put a pot shard or small, flat rock over the drainage hole to keep soil in the pot. The best time to plant is mid-October, except NarcissusPaperwhites. Do not mix different bulb varieties or types in the same pot when their growth requirements are different. Use a sterile potting mixture with a neutral pH that drains well. A store bought pre-mix or a homemade mix of potting soil that includes vermiculite or perlite works well for the best drainage.


Fill the pots halfway with soil medium and lay the bulb, root base down pointed end up. Position the bulbs, so they are barely touching each other. Cover with two inches of soil, barely covering the top of the bulbs. The top of the dirt should be just below the rim of the of the pot. Tamp down the soil lightly and water so the soil is moist, not drenched.


Now they are ready to be placed in a cool, dark place. If you are fortunate to have a root cellar, it is an ideal location. The temperature should be maintained between 38°F and 45°F for approximately ten to twelve weeks. During this time the bulbs are developing their root system. If a root cellar is not an option, overwinter your potted bulbs in a trench outdoors. Dig a trench two feet deep and long enough for all your pots. Cover the pots with sawdust, straw, or hay. At least once a month, check the soil moisture. The dirt should be kept moist, not dried out or over-watered. The third option is a dedicated refrigerator. Humidity is a concern with a refrigerator. Put the potted bulbs in a plastic bag, either with a few slits for air or loosely closed on top to keep in humidity. Cool the refrigerator gradually, so as not to shock the bulbs, by lowering the thermostat in small increments until the desired 35°F to 40°F is reached. Check weekly and water to maintain a moist soil.


When the pots are ready for warm temperatures and light, a gradual transition is needed, too. Move them to a cool place with filtered sunlight, increasing temperature and light until buds emerge. During this time treat the small shoots with care, as they can break off easily. At this point, place them in direct sunlight with the temperature around 50°F to 60°F. To make the blooms last longer, keep the ambient temperature cool. The warmer the temperature, the faster the buds bloom and die off.



Avoiding the most common pitfalls just about ensures success. These include temperatures that are either too hot, which kills the flower bud, or too cold which kills the bulbs. Also, the longer bulbs remain unplanted, the greater the risk they become weak or rot. Maintaining a moist soil is just as important, as over-watering or drying out leads to your bulbs’ demise. Transition the bulbs slowly from the overwintering to the spring environment, as they naturally transition, to keep plants from stunted growth and shriveled buds. Should the stems flop over from large flowers, use a stake and twine or dental floss to tie them up.

Best Bulbs to Force

Forcing Spring Bulbs Indoors 2When forcing spring bulbs indoors, the most successful and easiest to grow are crocus, hyacinth, certain types of iris, narcissus, daffodil, and tulips.  Choose varieties labeled as ‘good for forcing.’  The following are good choices for forcing spring bulbs indoors.

Crocus: Blue Ribbon, Giant Yellow.

Hyacinth: Pink Pearl, Queen of the Pinks, White Pearl, Blue Jacket, Delft Blue.

Iris: All types of Iris, especially dwarf types, but not the bearded iris.

Narcissus and Daffodil: Most types work well. Narcissus Paperwhites is an exception to overwintering and not needing a cooling treatment, can be planted when purchased.

Tulips: These are the hardest to force due to a longer cold treatment of at least 13 weeks. Choose bulbs listed as early-flowering type.


Retail Outlets for Forcing Spring Bulbs Indoors

Many retailers offer the best varieties for forcing spring bulbs indoors. Be sure to follow the specific time frame and temperatures for the types chosen. As mentioned, Narcissus Paperwhites are an excellent choice for forcing spring bulbs indoors and the following plants are sold at Amazon.



10 ZivaPaperwhites 14-15cm- Indoor Narcissus: Narcissus Tazetta: Nice, Healthy Bulbs for Holiday Forcing!!

These beautiful scented flowers are a lovely accent for the holidays. They come in a six-inch planter and grow 16″ to 20″ tall.


Quaint Paperwhite Holiday Gift Growing Kit, Includes 5 Paperwhite Bulbs, a plastic pot and saucer, and Professional Growing Medium, by Daylily Nursery.

Though it takes 30 to 45 days to bloom, it makes a wonderful present that will cheer up friends and family during the ending months of winter.

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