Sow Vegetable Seeds
Sow warm-season crops such as squash, black-eyed peas, snap beans, cucumbers, melons, and okra. You can also sow a late crop of radishes and carrots to mature before summer. Work a 4- to 6-inch layer of compost into the planting bed, as desert soils are low in organic matter. Loosen the soil to a depth of 18 inches to allow roots room to grow.
Water Deciduous Fruit Trees
Keep peach, apricot, and apple trees well watered--to a depth of 3 feet for established trees and 2 feet for newly planted trees. Fruit is sizing in late April and early May, and a consistent moisture supply is essential. Thin fruits to a 6-inch spacing to allow remaining fruits to grow and mature to full size.
Control Blossom End Rot
Blossom-end rot may show up on tomatoes this month. It appears as a bruised-looking spot on the blossom end of the fruit. It's probably caused by uneven watering and a calcium deficiency. Prevent this problem by watering slowly and deeply to a depth of 1 foot, maintaining even soil moisture with mulch, and applying gypsum as a calcium source.
Fertilize Blooming Roses
Roses are in their peak bloom. To keep them looking great, water them to a depth of 2 feet and fertilize them with a rose fertilizer, a balanced fertilizer such as 10-10-10, or a combination of organic fertilizers such as fish emulsion and bone meal. Potassium usually isn't lacking in desert soils and shouldn't be added.
Temperatures are heating up, and landscape plants will need more frequent watering. Look for signs of stress such as wilted, drooping, or yellow leaves and shrunken tissue on cacti and succulents. It isn't necessary to increase the amount of water applied, but you will need to water more often.