Winter blues? FORCE BULBS INDOORS

Winter blues? FORCE BULBS INDOORS

By LINDA C. DOLAK

OSU Master Gardener Volunteer

111

Making a bulb flower at a time other than its normal time is called forcing. This practice is commonly used on daffodils, hyacinths tulips, crocus, tulips, Dutch iris, netted iris, snowdrop, grape hyacinth, and star-of Bethlehem. Daffodils and hyacinths are usually the easiest bulbs to force.

Several types that are considered difficult to force are Alliums, Camassia, Lilium and Scilla species. These bulbs require techniques used in professional greenhouse conditions.

According to a 2012 Rutgers University study, flowers have a direct effect on happiness. Flowers can bring positive feelings when they light up a room. Imagine seeing a bowl or pot of bright red flowers when it is cold and snowy outside.

To be successful, you will need large, good quality bulbs, pots that are 4 to 8 inches in diameter, and well-drained potting media. There are basically four steps to forcing your bulbs: selecting appropriate bulbs, planting the bulbs, cooling the bulbs, and forcing the flower.

Appropriate bulbs should be those recommended for forcing. These usually can be found at your favorite garden center. It is easiest to force bulbs that already have been cooled.

Look on the package or ask for that information at the garden center. Always handle your bulbs with care. These living plants should not be dropped or stored in extremely high or low temperatures. If you are not going to plant your bulbs immediately, they can be stored for up to two weeks in the refrigerator in a mesh or paper bag with holes. Do not store them along with ripening fruit or vegetables because the fruits and vegetables give off ethylene gas which can be harmful to the bulbs.

Another thing to remember: Some bulbs are poisonous. So, this method should not be used in a home with young children. Be sure to choose bulbs that are large, firm, and unblemished. If your bulbs are the type with a paper covering, choose ones with the paper intact, no mold, and no sign of decay.

Cooling is a necessary process for your bulbs to bloom if they have not been cooled or “pre-chilled” (so-called hardy bulbs). To chill your bulbs, put them in the refrigerator for 12 to 16 weeks to force the blooms. If your bulbs have been planted outside in the garden, this chilling process would naturally occur. Pre-chilled bulbs are available for forcing into bloom for Christmas.

When planting your bulbs, add enough planting material so they are at the correct level. When you fill the pots with your medium, leave about one-half inch at the top for watering.

Tulips and hyacinths should be planted with the tip of the bulb above the soil line. Daffodils should sit in the medium so half of the bulb is above the soil line. The smaller bulbs (crocus, grape hyacinths and snowdrops) should be one inch below the soil line. Allow at least 1 to 2 inches of soil beneath the bulbs.

Commercial potting soil is adequate. A better choice, however, is a mixture of equal volumes of potting soil, sphagnum peat moss, and perlite. Do not fertilize the bulbs because they already have enough food for the developing roots and flowers. The potting mixture must be well-drained, have adequate moisture, and be capable of holding the bulbs.

Do not press bulbs into the soil because you will compress it, and the roots will not be able to grow. Some people have good luck using some type of pebbles, coarse sand, or pearl chips. This can be fun because you can watch the roots grow.

If you plan to use clay pots, soak them in water overnight so that they do not take the moisture from the bulbs. Plant bulbs in clean pots that have adequate drainage. Plant them closely together in the pot. The flat side of the tulip should be placed next to the rim because the largest leaf will emerge first and grow on that side, making a nicer looking pot. Add water until it drips through the drainage hole. The blooms will last longer if the pot is moved to a cooler place at night.

After the cooling period, you should have a pot of beautiful bulbs in anywhere from two to four weeks depending on what types you choose. After the blooms are gone and the tops died down, you can transplant the bulbs outdoors so you can enjoy the color again in the spring.

For details, go to: go.osu.edu/forcing