The fabulous Philadelphia Flower Show—the nation's biggest and best—runs March 4 to the 11th at the Pennsylvania Convention Center in downtown Philly. This year it's a trip to The Emerald Isle! Details at their humbly named website, www.theflowershow.com
In honor of this upcoming Show of Shows, we interviewed master forcer John Story of Meadowbrook Farm on this week's edition of YBYG. John literally forces thousands of plants for each year's Show. Of course, a lot of the things he does to induce out-of-season bloom on big trees and shrubs are beyond the abilities of simple folk like you and I (giant coolers and freezers, high-intensity lights, supplemental infusions of CO2…).
But he says that almost anyone can force Spring bulbs—perhaps well enough to put up for a prize at their local Flower Show. And so, this week's 'Question' is a primer on bodacious bulb forcing. All you need to play along is a place that will stay nice and cool but not freeze for three months—like an extra refrigerator or an unheated but non-frosty garage or basement.
Timing? Some of the easiest bulbs to coax into bloom only require 12 weeks of chilling; these include crocus (especially the large-flowered types), those stinky hyacinths, and miniature hybrid daffodils. (Stay away from the full size ones—they need more sun than most people can provide indoors.) Two other tiny cuties—grape hyacinth and miniature iris—also force well, but need 16 weeks of chilling. So figure out how much chilling your bulbs require (see the link to the Netherlands Flower Bulb Information Center at the end of this article for help with this part) and then allow another 3 or 4 weeks for the blooms to appear afterwards.
Did you notice that tulips are NOT on our list of easy Spring bulbs to force? That's because they're not easy. But they are possible, especially if you can locate one of these specific red varieties: 'Brilliant Star'; 'Christmas Dream'; or 'Merry Christmas'. These only require 10 weeks of cold treatment, which is important because tulips are the fussiest about temperature swings during their chilling period, and 10 weeks is a lot less than the 16 it takes other tulips; a good 1/3 less, to be retentive. And they're red, making them the perfect Valentine's Day choice! (In the 'Language of Flowers', red tulips mean "I love you"; red roses only mean 'love' in general.) You can try and force other varieties of tulips—but like we said, they'll need at least 16 weeks of very even chilling.
To achieve that all-important chill, you'll need an extra refrigerator, or some other place that you're sure will hover around forty degrees but not freeze for three months (like that 'beer fridge' out in the garage!); and, of course, bulbs and pots. Any pots with drain holes will do; in fact in this case, the smaller the containers the better, so you can chill more of them in a small space.
Put a two-inch layer of a high-quality bagged potting soil (NOT garden soil!) in the bottom of the pot, then position the bulbs on top of this soil; their tops should be just the tiniest bit below the final soil line when they're covered. Really crowd the bulbs tightly—especially the tiny guys; that's how they look best when they're in flower. Then fill in around them with more potting soil, water well and place the pots where they can chill for the required number of weeks.
If you use a fridge, make sure it stays fruit-free during this time (gases given off by ripening fruit could cause the bulbs to sprout prematurely). And yes, you HAVE to pot the bulbs up (so they can grow roots); you can't just chill the naked bulbs. And again, DON'T use your garden soil; a nice, light premium bagged potting soil mix will really improve your chances of success here.
At the end of 'chilling time', bring the pots out, water them well and place them in a spot with good indirect light and temps in the low 60s for a week or so. Then, when the shoots are a few inches tall, move the pots into bright light (like a sunroom, a big, bright, clean South-facing VERY sunny windowsill or almost touching the 40-watt tubes of a four foot long florescent fixture) and provide higher temperatures (68 degrees is ideal) until the flowers begin to open.
When that happens, move the pots back into indirect light again, to keep the flowers fresh the longest possible time. They don't have to stay inside at this point; if you have room outdoors, you can put your forced pots outside anytime after the risk of a really hard freeze is over in your area. And you should; there's no light like good old sunlight!
If you start a run of 12 week bulbs in mid October, you should have home-grown flowers to present to your sweetie on Valentine's Day. Local Flower Show? Start three sets of bulbs each a week apart with the center set timed exactly for the show. That way, at least one set should be in peak bloom at Blue Ribbon time!
And finally, if you DO decide to do this, be sure to print out these instructions and put them in a Ziploc bag right with your pots, so you'll know exactly what to do when you take them out of the cold.
You'll find lots more forcing info at the Netherlands Flower Bulb Information Center's great site, www.bulb.com. Just click on "public" on the opening page, choose "Spring bulbs" from the list at the top and then choose "forcing Spring bulbs at home" from the list on the left; you'll find lots of great information, specific chilling times and even variety choices!