How to Force Bulbs Indoors

By November 25, 2019 November 29th, 2019 Gardening Inspiration and Advice
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One of the ways I love to beat the winter blues is to surround myself with flowers. The smell, the colours and new sense of growth tell me spring is on the way.

During the long Guelph winter, fresh flowers from the garden are hard to come by, but with a smidgeon of effort and planning, we can trick a spring-blooming bulb into flowering earlier than it would if you planted outdoors. Called “forcing”, but more like growing a seed, forcing a bulb allows us the opportunity to grow our own flowers and nurture life from start to finish—and it all happens indoors. Who says you can’t grow flowers in Ontario in the middle of January?

When I order bulbs for our garden centre, I select two kinds of forcing bulbs: one that does not need chilling (Amaryllis and Paperwhite Narcissus) and those that need a cold spell to promote a bloom. Hyacinth, large flowering Crocus, dwarf Daffodil, and Grape Hyacinth (Muscari) are all excellent choices for forcing but need some chilling time before they’ll flower properly.

Force-Free Forcing: For Easy Blooms

For fresh blooms all winter long, plant several batches of bulbs, each batch a week apart. Amaryllis bulbs are easy to plant indoors and ready to bloom! Sometimes decorative and wax-covered, they are a big bulb—about the size of your fist—and produce a collection of red, pink, orange or white trumpet-shaped blooms atop a tall, sturdy stem. The other indoor bulb that does not need any chilling is Paperwhite Narcissus. 

To force these successfully, choose your favourite container, fill with soil or layers of coloured gravel and plant so the bottom third of the bulb is buried. Water, place in a warm location and fragrant blooms will be yours three to five weeks after planting. 

If using gravel, layer the gravel up to 4” deep and plant your bulbs the same way you would with soil. Water so the bottom of the bulb barely touches the top of the waterline. If the water comes too high up on the bulb, there is a risk of rotting the bulb. 

Waxed Bulbs: The “Shortcut”

If you’re a real black thumb, there’s an even easier way to grow gorgeous flowers indoors; wax-covered bulbs! These bulbs require no “forcing” at all—in fact, they’re basically effortless. With wax-covered bulbs, all you need to do is place the bulb in a warm room and let nature takes it course – no soil, water or chilling required! We have a few gorgeous waxed amaryllis bulbs left in our nursery. You can pick a bulb covered in either gold or silver wax, and in a few weeks, they’ll bloom festive red flowers. 

How to Force Bulbs that Need Chilling

Crocus, most Hyacinth and Tulips need chilling to mimic the cold winter months. Before chilling, follow these easy steps for success and don’t be afraid to snuggle your bulbs together so they touch!

  1. Choose your favourite pot or a larger glass container and fill with gravel or good potting soil.
  2. Plant bulbs four to six inches deep (my rule of thumb is twice the depth of the bulb), and water like you would outdoors. When I feel adventurous, I layer my bulbs in a larger, deeper container – Narcissus on the bottom, then Tulips and Crocus near the top, so there will be multiple heights and blooms come the dead of winter.
  3. Chill your planted pot in a cold frame next to the house, unheated shed or cold indoor location like a three-season sunroom. The refrigerator works too, but don’t store the bulbs with fresh produce as the gases from fruit and vegetables can inhibit flower production.
  4. Keep the planted pots between 35° and 45° Fahrenheit (2° to 7° Celsius) until you see green tips—around 6 to 12 weeks. When the tips emerge, put the pot in a warmer location (60° Fahrenheit or 15° Celsius) with indirect light, until the leaves are a few inches long.

Once flower buds appear, move your pot into a bright, warm room.

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Container Choices

Use your favourite ceramic or clay pot, repurpose containers from your summer succulent planting or raid Grandma’s cupboard for a beautiful glass vase. Using clear glass will allow you to create a work of art, with layers of coloured gravel. Glass will also allow the kids to learn about root structures while they watch the bulb grow! 

That’s about all there is to it! Forcing bulbs is a low-effort way to continue gardening indoors through the winter, and their bold blooms are a fabulous reward. Stop by our nursery, just a short drive from Guelph, Kitchener-Waterloo or Cambridge, and discover all the colours hidden inside our bulbs.