By Karen Chang, U. C. Master Gardener
Every February we have a spell of warm, sunny days that makes people from the Midwest and East Coast question whether we in Northern California experience winter at all. However, we know that this is just a teaser before cold, wet weather sets in again.
As expected, spring started very early this year with more than a week of glorious warm, dry days and temperatures reaching a record 80ºF in the upper end of the Napa Valley before the middle of February. The flowering pears, tulip magnolias and camellias, all in full bloom, tried to convince us that winter was over.
But of course, this couldn't last; it's still winter. That gorgeous magnolia ended up with brown, wrinkled crepe paper in place of the blossoms when record low daytime temperatures and snow on Mount St. Helena and the Palisades followed. There is still the possibility of more frost in March and even until May in the upper valley.
So watch the weather and soil conditions and be prepared to protect your plants if frost is forecast. With warm temperatures and offshore winds, potted plants and seedlings may dry out, so monitor soil moisture closely.
Planting
Don't set out summer vegetables yet; plants are more susceptible to diseases in the cold soil. Plants set out at the correct time, in warm soil, will grow quickly and strongly and surpass those set out too early. Sow these seeds directly in the soil now: broccoli, cauliflower, chard, endive, lettuce, kale, peas, parsley, radishes and root vegetables. Start seeds of warm-weather vegetables in a warm, sunny location later in the month to transplant in late April or May, depending on your microclimate. These include basil, eggplant, peppers and tomatoes. Plant perennial flowering seedlings such as artemisia, columbine, coreopsis, dusty miller, penstemon, phlox, scabiosa and Shasta daisies. Plant summer bulbs such as amaryllis, caladium and gladiolus and tubers such as tuberous begonias, calla lilies and dahlias.
Soil management
When established shrubs and citrus begin active growth later in the month, feed with a balanced fertilizer such as 10-10-10.
Maintenance
Keep after those weeds. They just keep popping up, but a walk around the garden twice a week to pull the newly germinated ones will keep them under control. They are easy to remove at this time of the year. Don't mulch yet; wait until spring sunshine has warmed the soil. If you didn't divide overgrown clumps of fall- and summer-blooming perennials such as agapanthus, chrysanthemums, daylilies, Shasta daisies and yarrow, you can do so now. Replant the young outer portion of the clumps. Prune back herbs such as oregano and thyme by about half and remove dead branches to promote new growth. Watch for snails and slugs. There seems to be an extraordinary crop of slugs this season; one gardener reported 18-inch-tall kale plants dripping with the little critters. Aphids may appear on the fresh new growth of roses and fruit trees, so look out for them. Usually a strong blast of water from the hose will knock them off. Repeat a couple of times and that should take care of the problem. Check your irrigation system now when it's easier to get between the plants. Make sure emitters and sprinklers aren't plugged or broken. Remove the end of the tubing and flush the system. Check for leaks in the line and correct positioning around plants. Extend the drip area for shrubs and trees that have grown larger.
Harvest
Harvest fall and winter plantings of broccoli, chard, fava beans, green onions, kale, lettuce, parsley, peas, root vegetables and spinach.