Forcing Bulbs Indoors

Forcing Bulbs Indoors
I’ll Meet You in the Garden with Shellie Wise

If you love the intoxicating scent and beautiful colors of flowers but don’t want to wait for Spring to come, you’re in luck. Forcing bulbs indoors during the fall and winter months is relatively easy to do. Provide good light, cool temperatures, and regular watering, and you’ll be rewarded with cheerful blooms during the dark days of winter.

Most hardy bulbs need to chill to make them believe they are going through a winter period, but tender bulbs don’t need this process and can be started at any time. Amaryllis, freesia, and paperwhite narcissus are three such bulbs. Find these and the hardy bulbs at a local nursery, garden center, or online. There are three ways to force bulbs indoors - in soil, above water, or in pebbles above water.

Amaryllis are large bulbs. Select a pot just a few inches wider and taller than the bulb. Use an indoor potting mix with good drainage to fill the pot about 1/3 to 1/2 full. Give the bulb enough room for 3-4 inches of root growth. Place the bulb on top of the soil with the pointy side up. Fill in with a little more soil but leave the top third of the bulb sticking up out of the mix. Water the soil until it is as damp as a wrung-out sponge. Too much water will rot the bulb, so you may not need to water again for several weeks—water when you see new green growth emerging from the top of the bulb. Keep the soil moist but not soggy. Place the pot in a bright sunny location out of direct sunlight and away from drafts. The tall flowers become heavy, so place your pot into a heavier container or place several large rocks around the soil to keep the bulb stable.

Paperwhite Narcissus bulbs are smaller and can be planted in soil similar to amaryllis. Place several bulbs in the pot, pointy side up and close together. Cover with the potting mix, so the tips are just peeking out of the soil. It’s also fun to grow paperwhites in glass containers (mason jars, vases, fish bowls, candy dishes) filled with pebbles and water. A container with tall sides will help support the tall stems, or you can tie the stems together gently with ribbon or string. Fill the container with 1-3 inches of pebbles or stones. Add water, so it just reaches the tops of the pebbles. Place the bulbs on top of the pebbles, keeping them out of the water, and place the pot in a bright sunny location. Keep the water level to just barely at the top of the pebbles but below the bulbs so they don’t rot.

A fun fact…Dr. Bill Miller, with the help of Erin Finan, at Cornell University, found that using a diluted alcohol solution will keep your stems a third shorter than normal so no staking or support is needed. He suggests starting the bulbs in plain water. When roots have formed and the stems are 1-2 inches tall, pour off the water and replace it with a solution of one part hard liquor (gin, vodka, rum, tequila, etc.) to 7 parts water. Use this solution to water your plant. Nothing will be affected except the stem heights. https://blogs.cornell.edu/hort/2009/11/10/picklin...

Freesia corms are even smaller in size, so more of them can be planted in the pot. Similar to amaryllis, fill the pot with a well-draining potting mix of about 1/2 full. Place the corm on top of the soil with the pointy side up. Plant more corms in the same pot leaving about 1-2 inches between them. Add soil so that it just covers the corms. Water the soil so it’s as damp as a wrung-out sponge, and place the pot in a bright sunny location. Freesia flowers become top-heavy, so plant stakes in your pot for support, or you can gently tie the stems together with string or ribbon.

Anemones, crocuses, daffodils, hyacinths, irises, muscari (aka grape hyacinth), snowdrops, and tulips are some of the hardy bulbs that need to go through a cold spell to mimic winter. The chilling times, ranging from 6-15 weeks, are detailed in the table below. With these hardy bulbs, you are making them believe they are going through the natural process of winter. The bulbs can be chilled, placed loosely in paper bags, planted in jars above water, or planted in moist soil. A consistent temperature between 35-50°F is ideal. If kept in a refrigerator, keep them away from fresh fruit. The ethylene gas given off by the fruit, especially apples, interferes with flower formation in the bulb. During this fake winter, the bulbs are growing roots. Once a good mass of roots has started growing on the bulbs in paper bags or in the jar of water or when 2-4 inches of stem growth is showing on the bulbs planted in moist soil, they are ready to move into their blooming period. Plant the bulbs from the paper bags into a pot filled with potting soil allowing 3-4 inches of root growth. Be careful not to destroy the roots. Anchor the bulbs in with more soil, but there’s no need to bury the bulb. Tulips have a flat side on their bulbs. The largest leaf grows on that side, so facing it towards the outside of the pot looks nicer. Move the planted pots and jars of water to a spot where temperatures remain around 60-65°F, and there is dim light. Within a week, give them bright light but maintain the cool temperature (60-65°F) to mimic Spring. Keep the soil evenly moist but not soggy. In the glass jars, keep the water line below the bulb so it is not touching the water.

BULB	CHILL PERIOD	BULB	CHILL PERIOD
anemone	8-10 weeks	irises	13-15 weeks
crocus	10-12 weeks	muscari	6-10 weeks
daffodil	14-17 weeks	snowdrops	15 weeks
hyacinths	10-14 weeks	tulips	10-16 weeks

Last updated November 9, 2021