By Karen Chang, U. C. Master Gardener 

November brought Napa Valley a range of weather. We had a taste of winter, with some light rains and temperatures down to 38ºF in some areas. Then we had some unseasonably warm temperatures, up to 80ºF in Calistoga.

Late fall and early winter rains can be unpredictable. If rain arrives in force, avoid digging in or walking on wet soil. However, if rain is light or sporadic, continue to run your irrigation system as needed.

Watch for frost warnings and protect tender plants such as bougainvillea, citrus, fuchsias and succulents when frost is expected. Remove any covering when the temperature rises. Frost cloth can remain in place. If you experience frost damage, resist the temptation to prune; wait until spring when the new growth appears, even though the plant with damaged leaves may be unsightly.  

 

Soil management

• If you prepared holes earlier for dormant planting, cover the holes with plastic sheeting to keep the soil from becoming too wet to work.
• The benefits of raised beds become apparent now. They should drain quickly and be ready for planting when the rains taper off.

Planting

• Bare-root cane berries, fruit trees, grapes, roses and other deciduous flowering trees usually show up in the nurseries as soon as the Christmas trees are gone. Plant them as soon as possible after purchase or keep the roots covered with damp planter mix or sand in a shady spot so that they won't dry out.
• Sow these vegetable seeds directly into the soil: fava beans, radish, shallot and spinach. Wait until after the soil begins to warm in March before planting other seeds.
• Set out seedlings of broccoli, cabbage, cauliflower and lettuce and crowns of artichokes and asparagus.
• Alyssum, calendula, pansy, primrose, stock and viola are good color accents that can still be planted in planter boxes or pots in a sunny spot now.

Maintenance

• Harvest all olives, including those on the ground. If you don't plan to press them for oil or cure them, you should still harvest, bag and discard them to prevent the spread of the devastating olive fruit fly. The flies are mobile and move easily from residential landscape trees to infest commercial groves.
• Start pruning deciduous fruit, nut and shade trees. Don't prune evergreen trees, shrubs, roses or vines now or you may stimulate new growth that could be damaged by frost.
• Apply dormant spray to fruit trees and roses. Dormant-oil sprays kill over-wintering insect eggs, mites, soft-bodied insects and some types of scale. Peaches and nectarines also need a spray of fixed copper or Bordeaux mixture to prevent peach leaf curl. For complete coverage, spray the branches, branch crotches, trunk and ground beneath the drip line.
• Keep leaves and litter picked up to discourage pests from over-wintering in your garden. Dispose of diseased leaves and trimmings in the garbage.

Harvest

• Bring in the late summer and fall crops: broccoli, brussels sprouts, carrots, lettuce, peas, radish, spinach and root vegetables.