BY HALEY PAUL
|Photo by Diana Lustig|
For those in the low desert of Arizona, the arrival of the cool weather is a welcome respite from the searing days of summer. From Phoenix to Tucson, winter gardening is a great way to get outside during the best time of the year. However, the cold weather can come fast—seemingly overnight with the first frost. Although the fall (August through October) and the spring (late February through June) are ideal for gardening, keeping up the gardening momentum during the winter months (November through February) offers certain challenges and opportunities.
In the challenges column, there are those pesky frosts to consider, and the weather can be unpredictable. According to the University of Arizona’s Climate Assessment for the Southwest (CLIMAS), forecasters originally projected “at least a moderate El Niño event this winter,” which would likely bring wetter conditions, generally colder temperatures, and more frequent, harsher frosts. However, current climate models suggest a weak El Niño event, at best.
With the uncertainty at hand, it is best to be prepared and plant varieties suited to the Arizona desert’s winter climate, while being mindful of planting dates, and the days or months until harvest.
Use a Planting Calendar
Arizonans are fortunate because it is possible to grow a garden indoors and outdoors during the winter months by following the Southwest planting calendar.
Using the planting calendar not only helps determine what to plant and when, but also how long it will take for that plant variety to mature and become harvestable. “Time to harvest” is an important factor to consider because planting a vegetable variety too late or too early in the season can impact the bounty of the crop. For instance, some plants will react dramatically if temperatures suddenly increase. Take lettuce, for example: it bolts, sends reproductive flower stalks up and out of the plant, and then turns bitter to taste. Once lettuce does this, it is no longer viable for harvest. Finding the right time to plant is sometimes a moving target, and perfected only by gardening experience and luck (depending on the weather). Using the planting calendar can help guide decision-making regarding when and what to plant in the garden, and (hopefully) reduce the amount of lettuce lost to its desire to reproduce.
When it’s too cold outside, growing indoors, in a warm, controlled environment, can keep plants productive. If indoor space is a concern, a good solution is hydroponic gardening.*
Take cover! Protect plants from frosts and create artificial warmth
Planting the right variety of crop is not the only factor for creating a successful winter garden. Generating warmth is another key concern, as cold temperatures can slow plant growth. With the plentiful winter sunlight, however, warmer garden temperatures can be achieved with a little human intervention.
- Use fabric: Garden cloth and fabrics are available to drape over plants in the garden. Remember to listen to the weather reports and cover your garden accordingly.
- Warm the soil: Artificial and natural mulches can help keep the soil warm (and suppress weeds). Place reusable black plastic or wood chips in between winter vegetables to hold in soil moisture and warmth.
- Position garden for success: If possible, locate winter gardening activities on the south-facing portion of the yard and take advantage of the light and warmth created by the sun’s movement across the winter sky.
- Create shelter: Tunnels are a great way to keep plants protected and warm in the winter. Create the tunnel with construction mesh covered with clear plastic or cloth.
- Add garden trenches: Create row depressions by scraping about five inches below the surface of the soil and planting in the trenches, which can protect vegetables from wind and other winter elements. Add some clear plastic on top, hold it down with bricks, and create an in-the-ground greenhouse effect.
*Read more about hydroponics in our article Hydroponics 101 at greenlivingaz.com
Got a gardening question? Contact the Maricopa County Master Gardener hotline at (602) 827-8200 x301.
Haley Paul is an Assistant in Extension in Urban Agriculture at the University of Arizona
Cooperative Extension (UACE) in Maricopa County, a unit within the College of Agriculture and Life Sciences. Find your local Cooperative Extension office at
http://extension.arizona.edu. email@example.com, @haleyepaul