- Continue to care for indoor seedlings by providing sufficient light and water.
- Begin to transition your indoor seedlings to outdoor climate increasing number of hours each day.
- Start caladium tubers in moist sand or sphagnum at 65 degrees.
- Cyclamen will go into their summer rest. Let them slowly dry off, set pots in a cool cellar, and water only enough to help the bulbs from shriveling.
- Be careful not to let plants burn in south and east-facing windows.
- Continue garden cleanup if not already done in March (see March listing).
- Plant potatoes, peas, beets, turnips, radishes, carrots, spinach, and other leafy greens. Thin seedlings of previously planted carrots, beets, and lettuce.
- Dig, divide, and replant perennials, such as helenium, fall asters, Shasta daisies, chrysanthemums, and phlox.
- Plant pansies, forget-me-nots, foxglove, and other cool-weather flower transplants.
- Sow seeds of sweet peas, bachelor’s buttons, and larkspur in flowerbeds.
- Visit your local garden center for best selection of plants. Prepare a list to buy based on the location of planting (sunny, shady, part-shade, acid, dry, etc).
- Protect transplants in the garden from cold and wind using milk jugs or other protective covering.
- Plant roses, trees, and shrubs.
- Starting a new lawn, fertilizing, or renovating a lawn with cool season grasses will be most effective if done during the peak growth period – from 65 to 75 degrees F.
- Apply pre-emergence herbicides to prevent seeds from germinating (crabgrass and other weeds). Read label for application timing. Two applications may be required.
- Late-flowering shrubs such as hydrangea, butterfly bush, althaea, franklinia, hould be pruned in spring, if pruning is needed.
- Transplant strawberries so that the crowns are just even with the surface.
- Fertilize blueberries with ammonium sulfate as well as rhododendrons, azaleas, and most other broadleaved evergreens.
- Asparagus grows best in a sandy loam. Set the plants 1 to 1½ to 2 feet apart in rows 4 feet apart.
- Remove cabbage worms as they appear, or treat for heavy infestation. Floating row cover is a good barrier if applied at time of planting.
- Apply lime around lilacs and clematis, cultivating it into the soil.
- Transplant cabbage, broccoli, lettuce, and cauliflower plants into the garden.
- Mulch flower and landscape beds. To prevent weeds seeds from sprouting, put down wet newspaper overlapping edges underneath the mulch.
- Near end of month plant a few gladioluses and continue every couple of weeks until early July to have continuous display.