Ask the ISU Extension Garden Experts: Onions, Cold Frames, Lenten Roses and Primroses

What are some good onion varieties for Iowa?

Suggested onion varieties for home gardens in Iowa include ‘Copra’ (main season, yellow-brown skin, excellent storage), ‘Candy’ (yellow-brown skin, globe-shaped, short term storage), ‘Red Burgermaster’ (bright red, globe-shaped, good storage), ‘Red Zeppelin’ (deep red, globe-shaped, excellent storage), ‘Stuttgarter’ (flattened globes, light brown skin, excellent storage, from sets) and ‘Walla Walla Sweet’ (late season, yellow-brown skin, short-term storage).

What would be a good location for a cold frame?

Cold frames and hotbeds are used to germinate flower and vegetable seeds of cool season crops in early spring and to harden off plants prior to transplanting outdoors. The primary difference between a cold frame and a hotbed is that a cold frame relies on solar heating, whereas a hotbed uses an additional heat source, such as electric heating cables or fresh manure.

A site with a southern exposure is the best location for a cold frame or hotbed. A southern exposure provides maximum sunlight and heating capacity. To reduce heat loss, position the north end of the structure near a home, garage or fence. For convenience, a nearby water source is helpful. An electric outlet may be necessary as a power source for a hotbed.

Can the Lenten rose be successfully grown in Iowa?

While more demanding than many other perennials, the Lenten rose (Helleborus x hybridus) can be successfully grown in Iowa. The Lenten rose requires a fertile, well-drained soil in partial shade. Also, choose a site protected from strong winter winds. The evergreen foliage of the Lenten rose may become scorched or tattered when subjected to strong winds in winter.

I recently purchased a primrose at a florist. How do I care for it?

Primroses are typically sold at florist shops and greenhouses in late winter or early spring. Plants produce attractive, one to 1-1/2 inch diameter flowers above a rosette of leaves. Flowers may be white, yellow, orange, pink, red, purple or blue. Many flowers have contrasting centers or “eyes.”

With a proper environment, primroses often bloom for several weeks. In the home, place plants in a cool (55 to 60 F), brightly lit location. Keep the potting soil evenly moist. Primroses decline rapidly if the potting soil dries out completely or remains constantly wet. Discard the plants when they are done blooming.

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