How to keep your Valentine roses for a longer period of time

If healthy cut roses suddenly develop drooping heads, it may be due to air bubbles trapped in their stems.

Float the entire stem in a sink full of warm water. Trim another inch from the stem, cutting on an angle below water level. Try to gently straighten the drooping flower head as the flower and stem continue to float, and the cut end of the stem remains under water for at least one-half hour.

When the flower head hardens to a straightened position, the roses may be placed back in the vase.

• Many homeowners apply too much ice melt to their walks, which then increases the chances for and extent of damage to plants and paved areas.

Ice melt products with calcium chloride tend to be easier on plants, so this is the product I use very sparingly at home. Try mixing ice melt with sand to control ice while reducing the amount of chemical used.

• It's time to start annuals that get off to a slow start, such as pansies, violas, petunias, snapdragons, and lobelia. Petunias and lobelia will be best planted outside after the danger of frost has passed.

While garden centers offer many favorites, the choices are seemingly endless when you grow your own. Use grow lights to ensure success. A florescent type hung on a chain works best, as you can adjust the level to keep the light at an optimum 8 to12 inches above the seedlings.

Providing bottom heat for the seedlings will also improve results. Heat mats or cables can be purchased at your local garden center.

Thin seedlings as needed, especially after the first set of leaves form to prevent overcrowding and keep the best plants. Be sure to sow a few extras, but not too many to make sure that you get the number of plants that you intend to use.

• Tim Johnson is director of horticulture at Chicago Botanic Garden, chicagobotanic.org.