Just when you’re putting your outdoor garden to bed, it’s time to plan one for indoors to cheer you through the winter. Flowering houseplants can do the trick, but there’s another way to have spring on your windowsill in February – by forcing bulbs.

Spring-flowering bulbs go in the ground outside in autumn, because they require several months of chilling to form buds. But you can trick them into blooming in pots indoors by simulating that same big chill. So when buying bulbs for fall planting from garden centers or catalogues, order extra and you can have spring bouquets throughout the winter.

Almost any spring-flowering bulb will do, though some bulbs are marked on the package as good for forcing. Tulips, hyacinths, narcissus, grape hyacinths, and crocuses work well, are great for their colors, and can be potted in various combinations.

Bulbs do best in a soilless potting medium in shallow clay pots about twice as wide as deep. Put the bulbs close together for a showy display and have the tips just above the potting mix. Give them a thorough watering and store in a cool basement, unheated garage, old refrigerator, or cold frame where the temperature stays between 35 and 45 degrees. Don’t let them dry out (but water only as necessary) or freeze.

Most bulbs need to chill for about fifteen to eighteen weeks and will bloom two or three weeks after being brought into warmer conditions. For the first week of warming, let them adjust by keeping them around 60 degrees in indirect light, but then move them wherever you like; proximity to a sunny window will help the bulbs bloom more quickly.

So what’s the secret to having different bulbs in one pot bloom all at the same time? “A whole lot of knowledge and a little bit of guesswork,” according to Leslie Deal at Donaroma’s in Edgartown, where the staff starts different kinds of bulbs grow-ing separately instead of mixed together in one pot. With greenhouses and cold- storage options, Leslie says bloom time can be speeded or slowed as necessary. Then the staff takes bulbs out of their segregated pots and combines them. “We pick things we know will go together and we know how big the pot needs to be for the right depth and height of the bulbs,” she says.

If you’re after a high-impact look with everything on display at once, this is the way to go. But note that they’ll all die pretty much at the same time. Whereas if you start with different bulbs all mixed together, one pot can keep producing for several weeks.

If you don’t like looking at the empty spaces where you’ve cut dead flowers off, you can fill in with decorative Spanish moss or spring flowers, such as pansies and primroses, that are available at florists in late winter. That’s also a good way to disguise a spot if a bulb fails to bloom at all.

It’s easier to grow bulbs that don’t need to be pre-chilled. You’ll find paperwhite narcissus and amaryllis around the holidays at florists, garden centers, and even grocery stores either as bulbs or in pre-planted kits. Paperwhites don’t even need soil to grow; they can be potted in pebbles that are kept moist enough to nourish the roots.

I bought my paperwhites, pebbles, and a cylindrical glass vase at Donaroma’s for under $20 and potted them on December 18. Though pre-chilling is not required, keeping the bulbs in an area somewhat cooler than room temperature just until they sprout will promote stockier stalks. I put them in a room cooled to 50 degrees, and seventeen days later when they started to sprout, I moved them to a room that is about 68 degrees during the day and 58 degrees at night. In two weeks, the first bulbs began to bloom with the first flower fading about ten days later – but more buds were opening. I ended up with continuous blooms for more than a month from just five bulbs.

Amateur gardener Katherine Welch has been growing paperwhites in soil for several years but just tried amaryllis for the first time last winter. Her method? “I just plunk them in and hope they’ll do something.”

Rather than starting them all at once, Katherine stores some bulbs in the basement of her Edgartown home and then pots them up at intervals, so she has several pots in different stages. She places them in a sunny window in her living room, a room that is kept on the cool side. “They’re so fragrant and it’s just kind of fun to see them growing during cold weather,” Katherine says. “I come down every morning to see what changed overnight.”

Whether it’s a cold, snowy day in winter or a gray, rainy day during the mud season, indoor flowering bulbs hint at the promise of spring. u – susan catling