Homegrown: Gardening in a dry autumn

During these dry, late-summer weeks, landscape shrubs and trees continue to be at risk where irrigation has been lessened or withdrawn completely. Most trees withstand drier conditions than smaller rooted shrubs, but all landscape plants must have adequate moisture to survive.

Here are a few solutions to protect them from excessive stress or possible loss.

• Look around your neighborhood for any plants like yours facing similar conditions. If they appear normal or nearly so, yours likely have similar success ahead of them. Use what water you have available for irrigation on plants that are visibly needy.

• Water trees and shrubs with a very slow-running hose positioned at or just inside the drip line - the area below the outer edges of foliage. Monitor closely so there is no runoff.

• Move the hose around the circumference until there is moisture throughout the top 12 to 18 inches of soil under mature plants. Most roots lie no deeper than 2 feet below the surface, less for shrubs.

• Apply a deep layer of mulch over the irrigated area. Mulch can be any organic material, including disposables such as dead weeds, leaves, and garden trimmings. Test for moisture after 2-3 weeks.

Look on the bright side

With encouraging forecasts of el Nino bringing rain, relief is just over the horizon for trees and shrubs and a return of greenery. But before rains begin, it’s time to think about planting vegetables.

There are as many or more crops suited to growing in fall than at any other time. August and September are ideal times to sow or transplant beets and turnips, broccoli and cauliflower, cabbage and numerous greens of all types, carrots, peas, onions and leeks. Most crops will develop slowly and extend harvest into winter months.

If you’ve never tended an autumn garden, you may not realize how easy it is, especially when rains do the watering for us. It all begins with a little work, however, as any gardening demands.

You’ll need to put some effort into revitalizing a bed of soil with an inch or 2 of compost or aged manure, fortify with a balanced fertilizer, and mix in as deep as a spade’s depth before planting. Be cautious adding manure, however. If you can smell it, it’s too fresh and will burn plants.

Compost, the ideal organic amendment, helps hold moisture in sandy soils and facilitates drainage in clay, essential for both shallow and deep rooted plants. And compost feeds soil microbes that aid in the uptake of nutrients.

Special considerations

Of all crops that thrive in a fall and winter garden, onions demand the most special attention for one reason: timing.

They give us little leeway in a planting calendar because each type has a pre-determined response to hours of sunlight in a day. Planted at the wrong time, they bolt.

For a satisfying onion crop, grow those suited to our latitude and plant when they best respond to appropriate periods of light and darkness.

Of the short day, long day, and intermediate varieties, intermediate types are usually grown in our area.

Short-day types can do well here for some gardeners, but the vagaries of our weather often spell bad luck. In mild winters they should bulb up successfully,

Plant seeds now

For gardeners who like to grow onions from seed, the window is open in September for direct sowing of intermediate types including green or bunching onions, which can be grown year-round. If you’ve never grown any bulbing types, try Walla Walla, a sweet, mild and juicy favorite among home gardeners. Sow seed now and set out intermediate transplants from October through January.

Onions planted in fall and exposed to ever-shortening days develop strong root systems that hold through winter, but they don’t have time to develop much stem girth above ground. It isn’t until after the winter solstice in late December as days lengthen that stems enlarge more rapidly and bulbs begin to form.

If winters are excessively cold or have too many alternating warm and cold periods, many varieties will bolt or develop too slowly to be satisfying.

Keep an eye on the size of stems during the next few months. Plants with pencil-thin tops in January should continue to develop normally. Fatter stems by then will likely bolt, so harvest those early to use immediately or store short-term in the refrigerator.

Rosemary McCreary, a Sonoma County gardener, gardening teacher, and author of Tabletop Gardens, writes the monthly Homegrown column for The Press Democrat. Contact her at rosemarymccreary@gmail.com or write to her at 427 Mendocino Ave., Santa Rosa 95401.