Gardening RX > The Gentle Art of Persuasion
For gardeners, it is already time to think spring—tucking bulbs away in the flower beds and along stone walls, anticipating the first blooms of the season. But why wait for months? Enjoy early spring blossoms long before the snow has melted by growing them indoors in pots.
Because I usually go overboard buying bulbs in the fall, I pot up the extras to coax into bloom over the winter. Some varieties—such as early single tulips—are naturally easy to force. Daffodils—especially the mini-daffs such as ‘Tete-a-Tete’ or ‘Minnow’—are especially good for forcing. Hyacinths are a must-have because of their heavenly scent. Small bulbs such as crocus, Iris reticulata, Anemone blanda, snowdrops, scilla and muscari are most versatile, putting on a spectacular show if mass-planted in a large pot. Or pot up just a few in a small container to display in a pretty tea cup. Many spring blooming bulbs are now being marketed specifically for forcing and will say so on the label. Buy the biggest and healthiest bulbs you can find, and they will reward you with the best flowers.
When choosing and planting your indoor bulbs, be sure to consider their recommended temperature and moisture levels. Find a storage spot in your home that will supply the needed cold period and provide ample protection from rodents.
Potting the Bulbs
Potting is the easiest but messiest part of this process. I like to do it outdoors— just one more reason to be outside on a beautiful fall day. I use wide shallow pots, sometimes called bulb pans; mine are five inches deep and eight inches across. Any plastic or terra-cotta pot will do as long as it has holes in the bottom for drainage. The bulbs need a minimum of two inches of soil beneath them.
Fill the pots half to three-quarters full of fast-draining potting soil or soilless mix. No fertilizer is necessary because bulbs come packed with all the nutrition they need to produce this season’s flowers. Instead of planting the bulbs at the depths recommended for outdoors, place them in the pot, pointy side up, as close together as you want. However, don’t let them touch; if one should rot, it will spread and spoil the rest. A full pot gives a better display, and you can mix varieties in one container, as long as they have similar temperature requirements. When planting tulips, be sure the flat side of the bulb faces the rim of the pot—this is the side that will have the first large leaf, and it looks better draped over the edge of the pot instead of bunched up in the center.
Cover the bulbs with dirt to within an inch of the pot rim to allow for watering. Larger bulbs such as daffodils, tulips and hyacinths should have their noses sticking up out of the soil. Label the pots and mark your calendar with the approximate dates to bring the pots out of storage (generally between twelve weeks and fifteen weeks later. In the mean-time, water the pots well and put them in a cold, dark place to develop roots. Check the pots once a week, and water when dry.
To get spring-flowering bulbs to bloom indoors, you need to trick them into thinking winter has passed and it’s safe to come out. The key to success is finding a storage place that is accessible, cool enough and protected from marauding rodents. On first thought, the refrigerator seems perfect: the temperature is correct—between thirty two degrees and forty-eight degrees is best—and the mice haven’t figured out how to gnaw their way in yet. Alas, newer frost-free models are just too dry, and the ethylene gas given off by ripening apples, oranges and veggies will cause the embryonic flower buds inside the bulbs to wither.
Most books recommend digging a deep trench, putting the pots of bulbs in there, covering them with dirt or leaves, and digging them up between twelve and fifteen weeks later—a suggestion that’s not terribly practical in our climate. If you are lucky enough to have a cool basement or unheated room in your house that doesn’t get below thirty-two degrees in the winter, this is the ideal place to give your bulbs their cold treatment. I’ve tried keeping mine on the floor of my pantry, in a cold upstairs closet, under the bed in the spare room and in the coldest corner of the greenhouse. Surprisingly, the pantry has worked the best.
It is okay if the spot you choose cools down gradually as winter sets in. Storing the bulbs for three or four weeks at between forty degrees and sixty degrees, and then lowering the temperature to between thirty-two degrees and forty degrees for the remaining time mimics the natural drop in soil temperature the bulbs would experience if planted outside. If you’re afraid they might freeze, put the pots in a styrofoam ice chest or a box filled with packing peanuts for insulation.
The pots also need as much darkness as possible, but don’t stack them—the bulbs need room to send up their shoots. Most bulbs need between twelve weeks and fifteen weeks of cold treatment before they are sufficiently rooted and ready to bloom. Before bringing the pots out of cold storage, check the bottoms for roots—even if the bulbs show some top-growth. If they aren’t well-rooted, give them more time in cold storage, as 90 percent of all forcing failures are due to a lack of good roots.
When the bulbs have rooted, you can start bringing pots out of cold storage. Don’t worry if new shoots are white, they’ll green up in the light. To prevent “blasting”—or shriveling—of the flower buds, introduce them to the warmth of the house gradually by placing them in a cool (between fifty-five degrees and sixty degrees), bright spot away from any heat source for between two weeks and three weeks while leaves and stems develop. A north window is ideal, as strong sunlight at this stage is a killer.
When buds begin to color, move the plants to a bright, sunny window to stimulate blooming. Most bulbs will begin to bloom in between two weeks and five weeks. Because I grow my bulbs in boring plastic pots, I slip the pot and all into more decorative containers for display. But once the flowers open, move the containers—keep them out of direct sunlight to prolong the bloom time.
Start planting in September and in January, you’ll be able to enjoy a touch of spring when you need it the most. For Valentine’s Day flowers, plant the bulbs in early to mid-October. There is nothing nicer than a pot of fragrant hyacinths blooming on the windowsill when the ground outside still is covered with snow.