Q-Last fall I brought in many pots of geraniums. They have spent the winter in sunny windows and have gotten quite tall. There are numerous flowers but also a lot of dried-up leaves and some withered stems that are blackened at the base. How can I turn these into decent plants for setting outdoors when the weather warms up?
A-Cut all the main stems back to about 6 inches tall. Remove entirely any of the withered, blackened parts. Clean away any dead leaves that remain on the stems, most of which will be nearly or entirely leafless. Remove an inch of the surface soil and replace with fresh potting mix. Set to grow in sunny windows. When new shoots are 2 to 4 inches tall, pinch out the tip to induce branching.
Process all the parts you cut off, salvaging as many cuttings 4 to 6 inches long as possible. Discard all the dead leaves and any shriveled or discolored stems.
Take each cutting in turn and remove the lower leaves as well as the paper green or brown stipules that occur along the stem wherever leaves grow; these may seem insignificant but if not removed before planting they almost invariably cause geranium cuttings to rot.
Set the cuttings to root with at least one node where leaves once grew buried in the medium-which can be clean, sharp sand or a 50-50 mix of sand and sphagnum peat moss. Some professional growers set geranium cuttings directly in moistened Jiffy 7 peat pots.
Geranium cuttings root quickly in temperatures between 60 and 75 degrees, with bright light and all but the hottest direct sun. Keep the rooting medium nicely moist, neither wet nor dry. Promptly remove any leaves or stems that wither or show signs of rotting. Do not enclose geranium cuttings in plastic or cover with glass; lack of fresh air encourages rotting instead of rooting. Some manuals say to leave geranium cuttings to dry a few hours or overnight before planting. This may be valid in a humid environment, but in most growing conditions it is better to plant at once or within a few hours. One point all agree on is that using a rooting hormone powder is not necessary and may even be harmful.
Q-Are eggshells good for plants?
A-Crushed eggshells are an excellent addition to the compost pile, but I would not use them on indoor plants. Types that need a more alkaline condition can better get it from a generous dusting of dolomite limestone scratched into the soil surface and watered in. A spider plant prone to rot in the center, where new growth emerges, will often recover and outgrow this condition if given this treatment.
Q-How can I get rid of brown tips on my spider plant?
A-Trim them off with scissors. Be more careful in the future to keep the soil nicely moist; avoid extremes of wet and dry. Try fish emulsion instead of chemical fertilizer.
Elvin McDonald cannot answer all questions individually, but he will respond to questions of general interest in this column. Write to him c/o The Chicago Tribune, Room 400, 435 N. Michigan Ave., Chicago, Ill. 60611.