Ask the ISU Extension Garden Experts About: Water Grass and Storing Onions

Storing Onions

Got gardening questions? Call the Hortline at 515-294-3108, Monday-Friday from 10 a.m. to noon and 1 to 4:30 p.m., or send an e-mail For more gardening information, visit us at Yard and Garden Online.

How do I control water grass in my lawn?  
“Water grass” is a confusing name. Several plants are occasionally referred to as water grass. Two common lawn weeds that are sometimes referred to as “water grass” are crabgrass and yellow nutsedge.

Crabgrass (Digitaria spp.) is an annual, warm-season grass. Crabgrass seeds begin to germinate when soil temperatures reach 60 degrees Fahrenheit. Germination usually begins about mid-April in southern Iowa, early May in northern parts of the state. Crabgrass continues to germinate over several weeks from spring into summer.

While crabgrass seed germination begins in spring, plants don’t become highly visible in lawns until late spring/early summer. Crabgrass is a low growing, spreading plant with light blue-green foliage. The leaf blades are approximately 1/4 inch wide. Seedheads appear as several finger-like projections at the top of the main stem. Crabgrass grows rapidly during warm summer weather. Growth slows with the arrival of cooler temperatures in late summer. Plants are destroyed with the first hard frost in fall.  However, before it dies, a single crabgrass plant can produce thousands of seeds.

The best way to prevent crabgrass infestations in lawns is to maintain a thick, healthy lawn through proper mowing, irrigation and fertilization. Crabgrass will have a difficult time germinating and surviving in a thick turf. Gardeners who have had crabgrass problems in the past will need to apply preemergence herbicides in spring. 

The keys to successful control of crabgrass in lawns are correct timing of the preemergence herbicide application and proper application of the material. Preemergence herbicides should normally be applied in early to mid-April in southern Iowa, mid-April to May 1 in central Iowa, and late April to early May in northern areas of the state.

Yellow nutsedge (Cyperus esculentus) is a warm-season perennial. It is not a grass nor a broadleaf weed, but a sedge. The grass-like leaves are light green to yellowish in color and shiny in appearance. Yellow nutsedge is an erect plant. The stem near ground level is triangular. The leaves come off the stem in sets of threes. Yellow nutsedge reproduces by seed and small underground tubers called nutlets. Flowers are yellowish or yellowish brown and are borne on small spikelets. Yellow nutsedge grows most rapidly during the hot summer months. It is often found in wet or poorly drained soils.

Control of yellow nutsedge is difficult. Plants do pull easily. However, when plants are pulled some of the underground nutlets remain in the soil. Eventually, the nutlets sprout and the plants reappear. Several herbicides will effectively control yellow nutsedge in lawns. Effective herbicides include Basagran (bentazon), Dismiss (sulfentrazone), Certainty (sulfosulfuron), and SedgeHammer (halosulfuron). These materials are generally not available to home gardeners. However, they can be applied by professional lawn care companies.

How do you harvest, dry and store onions?  
Onions should be harvested when most of the tops have fallen over and begun to dry. Carefully pull or dig the bulbs with the tops attached.

After harvesting, dry or cure the onions in a warm, dry, well-ventilated location, such as a shed or garage. Spread out the onions in a single layer on a clean, dry surface. Cure the onions for two to three weeks until the onion tops and necks are thoroughly dry and the outer bulb scales begin to rustle. After the onions are properly cured, cut off the tops about 1 inch above the bulbs. As the onions are topped, discard any that show signs of decay. Use the thick-necked bulbs as soon as possible as they don't store well. An alternate preparation method is to leave the onion tops untrimmed and braid the dry foliage together.

Place the cured onions in a mesh bag, old nylon stocking, wire basket or crate. It's important that the storage container allow air to circulate through the onions. Store the onions in a cool, moderately dry location. Storage temperatures should be 32 to 40 degrees Fahrenheit. The relative humidity should be 65 to 70 percent. Possible storage locations include a basement, cellar or garage. Hang the braided onions from a rafter or ceiling. If storing the onions in an unheated garage, move the onions to an alternate storage site before temperatures drop below 32 degrees Fahrenheit. 

The storage life of onions is determined by the variety and storage conditions. When properly stored, good keepers such as 'Copra' and 'Stuttgarter' can be successfully stored for several months. Poor keepers, such as 'Walla Walla' and 'Sweet Spanish,' can only be stored for a few weeks.

Contacts:
Richard Jauron, Horticulture, (515) 294-1871, rjauron@iastate.edu
Willy Klein, Extension Communications and External Relations, (515) 294-0662, wklein@iastate.edu

One photo for this weeks publication: onions2.jpg

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