Gardening with Allen: Forcing fall plants to bloom is easy
By Allen Wilson for The Columbian
Published: October 16, 2021, 6:03am
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Last year I purchased pots of tulips and daffodils ready to bloom in January and February. Could I plant some bulbs in pots now and get them to bloom in January?
Yes, forcing bulbs to bloom early in pots is not a complicated process. It just takes a 12 week cooling process at 45 to 50 degrees after they are planted. If you have an extra refrigerator that you might use for cooling summer drinks, you are in business. Bulbs planted in late October would normally bloom late January to early February.
Bulbs can be planted in any container as long as it has bottom drainage. Small bulbs like miniature daffodils, crocus and grape hyacinths are often planted in 4-inch pots, while pots larger than 6 inches are used for most others.
Bulbs are spaced closer together in containers to give a better display. Typically they are spaced so they are almost touching. Bulbs are also planted shallower in containers to give them more room for roots to develop. Fill pots almost full with potting soil. Then push the bulbs slightly into the soil to seat them and cover with enough soil so the tips are just barely covered. In most cases you can fill the pots completely full to the top. When watered, the soil will settle just enough to leave a ½-inch space at the top.
After draining, place pots in the refrigerator. They will stay moist for several weeks, but check regularly and water when the soil begins to dry on top. Put a reminder on your calendar at about 10 to 11 weeks so you can begin checking them. There are two signs that indicate they are ready to come out for bloom. The tips of the bulbs will begin to show growth on top. White roots will begin to show in the bottom drain holes. Bulbs will bloom about 2 weeks after placing in normal room temperatures.
Just about any fall planted bulb can be forced into bloom. However, the taller tulips may need support. The Triumph tulip varieties are a good size for forcing.
I also like to plant bulb mixtures in tubs and planters without cold treatment for bloom at a normal time. In tubs, I plant the tallest in the center with medium size next and shorter ones on the outside. In planters, I plant the tallest in the back and shorter in front. I usually plant bulbs farther apart and a little deeper than in pots, depending on the depth of the container.
Then in April or May I plant annual flowers in between the leftover bulb leaves before they have turned yellow and brown. I remove the bulb leaves as they mature, leaving room for the annuals to grow to their normal size. The bulbs can be left in the tubs and planters to bloom again the next year. The fertilizer I apply to the annuals also feeds the bulbs and lets them grow back to full size.
