Remove Tender Bulbs From Storage
If you've stored dahlias, cannas, and other tender summer bulbs, check on them and toss any rotten ones. You can pot them up anytime indoors to get a head start on the season; it just depends on how large you want them to be before planting them in the ground (not too large) and how long you want to keep lugging them indoors and out (once days warm up) before they can go into the ground. Give them plenty of room to spread their roots in the containers.
Force Lily of the Valley
For an olfactory treat indoors, start some lily of the valley pips (be sure they've been prechilled) in pots of sand plus peat moss. Plant them close together in the pots, and keep them cool and in indirect light. They should bloom in about four weeks. Start some in April for May Day gifts.
Cut Back Geraniums
If you've kept your geraniums growing indoors this winter, be brave and give them a hard pruning to encourage bushy growth. Keep the soil moist but not wet and fertilize at half strength. Give them the sunniest window for the most sturdy growth and best flowering.
Use Horticultural Oil for Tree Pests
Spray horticultural oil on fruit trees, such as apples, plums, and cherries, to smoother any overwintering insects. Choose a calm day when temperatures are above 40 degrees F, and be sure to cover all sides of the branches. You can also apply it to evergreens to control spider mites and other insects. Carefully follow the instructions on the label for proper usage and appropriate plants.
Set Up a Cold Frame
Cold frames are handy for hardening off seedlings. You can make a simple cold frame by placing hay bales along the perimeter of a rectangle, and placing old windows or a glass storm door over the top. Purchased cold frames are convenient -- some have thermostatically controlled tops that open automatically when the temperature inside hits a designated point. Since the midday sun can heat things up quickly, this feature is especially handy if you're away for long stretches during the day.