Desert gardening will change quickly this month as plants (and people) prepare to face hot, harsh sun through the summer. The most important thing you can do for your plants is to monitor watering. Too much water harms plants, too little harms them and lack of deep watering hurts, too.
The best rule of thumb: Deep, infrequent watering is better than a daily sprinkle. What’s deep? Watering to penetrate the entire root zone of a plant and no more.
When water goes beyond the root zone, it keeps on going, wetting soil, but providing no benefit to the plant. The idea of deep watering is to push roots down, past the soil surface. Although a daily sprinkle might wet the surface of the soil, benefiting shallow roots, the surface is where the plants are exposed to the heat, sun and wind. Deep water encourages deep roots, making a stronger, healthier plant.
Here’s a guide to watering: Water to 1 foot deep for turf, annuals, cactuses, succulents and ground covers; 2 feet deep for shrubs; 3 feet deep for trees. How to tell the depth? Take a straight garden stake and push it down into the ground about 2 hours after you water. If it goes down 6 inches into the soil, then that’s how far the water went. It’s simple.
For the most part, new transplants and rose bushes need to be watered more frequently than desert-adapted plants and those that have been in the ground for more than a year.
This is a smaller growing season than winter/fall, but there are still lots of things you can plant from transplant and seeds.
– Plant seeds of basil, garlic chives, lima and snap beans, black-eyed peas, cucumbers, green onions, melons, okra and summer squash.
– Transplant basil, lemon grass, lavender, peppers/chiles, mint and rosemary.
– In May you’ll be able to put in peppers, malabar spinach, hibiscus for tea, okra, more squash and more melons.
The well-tended April garden is abundant with growing, blooming plants at their peak. A neglected April garden can be overgrown with weeds, in need of pruning and watering. Look around and assess what worked, what needs to be moved and which area could use a pick-me-up provided by flowering shrubs, sculptural succulents or ornamental grasses.
Check pots to ensure they are not drying out. Add mulch on pots and beds.
As conditions dry, ensure veggies and fruit trees do not suffer. Water in the early morning or early evening hours. Tomatoes in particular can fall victim to various ailments if their water supply varies significantly. Check citrus trees, whose shallow roots can suffer when conditions are very dry.
By mid-May place 50 percent shade cloth over tomatoes to keep leafhopper insects away and to prevent curly top virus. The virus affects more than 150plants in the Southwest, severely stunting and killing vegetable plants. We have 50 percent shade cloth at Southwest Gardener.
Continue to deadhead annuals and perennials to promote more flowers.
Begin fertilizing Bermuda-grass lawns during early May.