Transplant tomato seedlings in the low desert now, but provide protection from late frosts until mid-March. Tomatoes like a rich soil, so incorporate plenty of compost into the planting area. The organic matter will also help retain moisture. Dig a hole the same depth as the container and twice as wide. Mix a phosphorus-rich fertilizer such as bone meal into the bottom of the hole, as well as a nitrogen-rich fertilizer such as blood meal or alfalfa meal. Keep soil consistently moist.
Maintain Cool-Season Flowers
Deadhead cool-season flowers such as petunias to promote continued bloom. Layer more compost as a mulch around plants. Temperatures are starting to warm up slightly, and cool-season plants are ready to put out a new burst of growth and color. Scratch a granular complete fertilizer into the soil around plants and water it in well.
Fertilize overseeded ryegrass lawns with 5 pounds of 21-7-14 per 1,000 square feet. Reduce watering as needed during rainy periods. Normally, watering every 5-10 days is sufficient. Make sure water penetrates at least 4-6 inches deep to soak the entire root system. Don't mow wet grass, which promotes the spread of fungal diseases. If you have a dormant Bermuda grass lawn, don't fertilize it.
Watch for Powdery Mildew
With increased rainfall, cool temperatures, and humid conditions, powdery mildew fungal disease is appearing in plants. It resembles a white powder on foliage and often strikes crowded plants with poor air circulation. To prevent it, leave the appropriate spacing between plants so they can grow to their full size without crowding. Remove any affected foliage immediately and discard it. Clean pruning tools so as not to spread the disease. Spray off foliage with water - this is one of the few fungal diseases that doesn\'t spread in wet conditions. As a last resort, dust with sulfur when temperatures are under 90F.
Continue harvesting citrus, especially navel oranges, which are near the end of their season. The longer citrus stays on the tree, the sweeter it becomes. (It will not sweeten after picking.) Taste-test every few days for sweetness. Clip fruit off with pruning shears, rather than pulling it, which can damage stems. If you have not already done so, fertilize citrus with its first feeding of the year.