Forcing bulbs isn’t as strenuous as it sounds. You aren’t actually forcing the bulbs, just fooling them. Instead of letting them winter out in the garden beds, they will winter in pots in a protected area that stays consistently cool. And - most unlike nature – you will control when winter starts and when it ends.
1. Decide when you want the bulbs to bloom
Some bulbs need a longer chill than others. Crocus and other small early-blooming bulbs need as little as six weeks. Tulips should have as much as twelve weeks of cold. So, if you wanted pots of tulips and crocus to be blooming on January 15th, you would have to follow this schedule. Please note that all dates are estimates; the bulbs you choose and your particular conditions affect when the bulbs are ready to bloom.
You don’t have to stick with winter blooming times. If there’s a cool dark spot somewhere from May to August (like a refrigerator), you could surprise someone with daffodils in August. Forcing bulbs can be done year-round.
2. Find a place to chill the bulbs
You’ll need a place that stays around 40 degrees. This can be an unheated garage, a cold frame, an attic, or anywhere else. Or, if you would rather keep them outside, pot up the bulbs and bury them in the ground. Getting them out may be a little more challenging when the ground is frozen and covered in 2 feet of snow.
3. Choose your bulbs
Many flower bulb companies will tell you which bulbs are best for forcing. Even without that information, crocuses, tulips and especially daffodils (aka narcissus) are easy. Let daffodil bulbs chill for about 14-16 weeks. Don’t be limited to these three choices, though. Try specialty bulbs like snow drops or winter aconite. Hyacinth bulbs and Dutch iris bulbs are also fun.
4. Get the pots ready
Clay pots breathe well, but any container with a drainage hole will do. Be sure to have enough room for the bulbs to have 2-4 inches of soil below them and be covered up to their tips. Bulbs should be spaced half an inch to a full inch apart from each other. Follow the Ikebana (Japanese flower design) rule of using odd numbers of bulbs – 5, 7 or 9 to a pot look best. If you are using bulbs that have a flat side (like tulips), face the flat side towards the outside of the pot so the leaves spread out nicely. When you are done the soil level should be about one inch below the rim of the pot.
Regular garden soil will do for forcing bulbs, but the bulbs will be less depleted after their indoor show if you give them a handful of compost in the pot, or use a weak solution of high-phosphorus, low-nitrogen fertilizer. As always, use the fertilizer sparingly; you don’t want to burn the roots. Water the pots thoroughly before you put them in the wintering spot you’ve selected. If you are concerned about the temperature rising or falling sharply, or about them drying out before you can check them again, cover them in towels or newspapers or whatever is handy.