Henry Homeyer: Tips for forcing bulbs for indoor blooms in spring
It might be nice to take a week in February or March and travel to the Caribbean. By then most of us are tired of snow and cold. But if that is not in your budget, perhaps you need to plant some bulbs in pots for spring forcing. I do it every year, and it brings joy to my heart just when I need it.
First, the basic concept: bulbs need a certain time in a cold, dark space to get ready to bloom in spring. But you can create that in a pot, and trick them into blooming earlier than they would outdoors in the ground. When you bring your pots into the warmth of the house, those foolish bulbs think it is spring — in February or March.
Each type of bulb needs a different length of rest in a chilly place in order to bloom. Small bulbs need about eight weeks, daffodils 12 weeks, and most tulips do best with 15 weeks. Tulips should never be brought up into the warmth of the house before February or they might just produce foliage, but no blossoms.
The hardest part of forcing bulbs is finding the correct spot to place the pots. Ideally, you will have a place that is 35 to 45 degrees. A place that is usually below 50 degrees and above 32 degrees works best. If you have a garage that is usually above freezing, that will work fine.
A few days of sub-freezing temperatures are not a problem. What you want is for the bulbs to send out roots in the pot, which they will do in November and December in your garage or on the steps out of your cellar through the bulkhead. I suppose you can also put a blanket (or a trash bag full of dry fall leaves) over the pots to keep them warmer in the coldest part of January.
Each fall I fill up a wheelbarrow with potting soil and compost, a 50-50 mix. I generally use the potting soil that I used in summer for annuals on the deck. The mix should be fluffy, contain no roots, and be lightly moist to start the process. I fill the pot one third full, place my bulbs, and then fill to within an inch of the top of the pot.
When buying bulbs to force, look for packages that say "Good for Forcing" or "Early Season Bloomers." "Darwin" tulips are generally good forcing, and are for sale at garden centers and grocery stores. Early daffodils force better than late season varieties.
One year I ignored my bulbs for forcing until it was time to take them out of my cold basement. I had very few blooms. Why? Because they dried out. I should have checked the soil once a month, and watered lightly. Bulbs don't want to sit in soggy soil, but they can't grow roots and get ready to bloom if the soil gets bone dry. It's a balancing act. The soil should be lightly moist.
Outdoors mice and squirrels can be a problem, as they consider bulbs good high-protein, high-calorie meals. I've read that during World War II, some Dutch farmers ate their tulips to keep from starving. Rodents think along similar lines. Daffodils and alliums are not of interest to rodents.
I live in a home built in 1888 and despite my best efforts, a few rodents sneak in and out at will. So I have to protect my indoor bulbs from them. I do this by placing a plate over the top of a round pot, or cutting a piece of wood to put over rectangular ones. This keeps the mice at bay.
Come spring, bulbs will start to grow and push up out of the soil. Still, I label each pot with the date it was planted and what is in the pot. That will allow me to bring up early bulbs before the tulips.
You can plant two layers of bulbs in larger pots. Set your large bulbs, the daffodils, tulips and alliums, near the bottom of the pot, but be sure to have 2 inches of soil below the bulbs. Add soil mix and then plant a layer of crocus or glory-of-the-snow (Chionodaxa luciliae) so that they are near the top of the pot. Bring out the pot into the warmth of the house when it is time for the larger bulbs. The little bulbs will bloom right away, followed by the bigger ones which can take three to four weeks to bloom.
Can you re-use forced blooms? Sure. Keep them in a sunny windowsill and water as needed until the soil has thawed outdoors. Plant them in the spring just as you would in the fall. They might need a year or more to recover from their indoor adventure.
Paperwhites, a type of daffodil commonly sold for forcing in pots of gravel and water, don't need the long chilling period of other bulbs. They are not hardy in our climate, however, so don't bother planting them outside in the spring. They can go right in the compost pile.
There is something very satisfying to me about being able to have tulips and daffodils blooming in my house while snow is still on the ground. I know I will have hundreds blooming in May, but having a few early ones indoors helps me through the gray days of mud season.
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