April in the Garden

Transplant onions early. A long period of strong green growth in spring will translate into the development of large bulbs in summer.

Complete outdoor spring seedlings of root vegetables, peas, cabbage, broccoli, and cauliflower. Seed nasturtium, clarkia, alyssum, nigella (love-in-a-mist), cornflower, candytuft, godetia and sunflower outdoors.

Wait until the warmth of May to transplant popular cold-tender flowers such as zinnia, marigold, geranium, petunia and impatiens, and heat-loving edibles such as eggplant, peppers, cucumbers, melons, and tomatoes except cold-tolerant varieties like Oregon Spring.

Plant dahlias and gladioli, and potatoes this month.

Plant baskets with cold-tender flowers if you have a place to keep them sheltered until warm weather.

Remove about a third of the old soil in large containers and replace it with fresh. Mix a little slow-release fertilizer into the top soil layers.

When the ground is dry enough, rake lawns thoroughly, aerate if the soil is compacted, and fertilize.

As you work in the garden this month, watch for suitable empty spots where spring bulbs could be planted in the fall. Note the sites in a garden diary, or post stick-on reminders in the pages of a calendar at the appropriate planting times.

Seed root vegetables outdoors this month, along with lettuce and dill, nasturtium, candytuft, alyssum, cornflower, sunflower, clarkia and godetia. Make indoor sowings of zinnias and marigolds, basil, cucumber, squash, pumpkin and melons, Brussels sprouts, and fall and winter cabbage.

Lettuce, carnations, sweet peas, calendula and stocks can be transplanted into the garden this month. But wait until the warmth of May to transplant cold-shy plants such as geranium, petunia, impatiens, peppers, eggplant, and most tomatoes. For hardy tomatoes, see the monthly reminders for February.

As soon as flowering has finished, prune forsythia, flowering currant and other deciduous shrubs that bloom early in the spring.

When preparing wire and moss hanging baskets this month, boost their moisture retention capacity by setting a plastic saucer inside the base.