When to Plant Tomatoes in Southern Arizona

Southern Arizona is known for its hot and dry climate, which can make planting tomatoes a bit tricky. If you're a beginner gardener or new to the area, it's important to know the best time to plant tomatoes in order to ensure a successful harvest. In general, the best time to plant tomatoes in southern Arizona is in late February or early March, but there are a few factors to consider before getting started.

Factors to Consider

Before planting tomatoes in southern Arizona, there are several factors to consider. First, you'll want to make sure that the soil has warmed up enough for the seeds to germinate. This typically occurs when the average daytime temperatures are consistently above 60°F. You'll also want to consider the frost dates in your area, as tomatoes are susceptible to frost damage. According to the USDA's Plant Hardiness Zone Map, southern Arizona is in zones 9a and 9b, which means the average annual minimum temperature ranges from 20 to 30°F. This means that frost can occur as late as mid-March, so it's important to keep an eye on the forecast. Finally, you'll want to choose a location that gets plenty of sunlight and has well-draining soil, as tomatoes thrive in warm and dry conditions.

How to Plant Tomatoes in Southern Arizona

Once you've determined the best time to plant tomatoes and have selected a suitable location, it's time to get started. Here are the steps to follow when planting tomatoes in southern Arizona:

Prepare the soil: Add compost or other organic matter to the soil to improve its texture and fertility.

Plant the seeds: Plant the seeds about a quarter-inch deep and space them about two feet apart. If you're planting seedlings instead of seeds, make sure to space them at least three feet apart.

Water thoroughly: Water the seeds or seedlings thoroughly, making sure that the soil is moist but not waterlogged.

Mulch: Add a layer of organic mulch, such as straw or shredded leaves, around the plants to help retain moisture and suppress weeds.

Fertilize: Once the plants have established themselves, you can begin fertilizing them with a balanced fertilizer every 2-3 weeks.

Support the plants: As the plants grow, you'll want to provide support in the form of stakes or cages to keep them from becoming too heavy and falling over.

Harvest: Once the tomatoes have ripened, you can harvest them and enjoy the fruits of your labor!

Troubleshooting

Despite your best efforts, there may be a few challenges when planting tomatoes in southern Arizona. Here are some common issues and how to address them:

Blossom drop: If the flowers on your tomato plants are falling off before they can form fruit, it may be due to high temperatures or a lack of pollination. Try shaking the plants gently to help pollinate them, or provide some shade during the hottest parts of the day.

Blossom end rot: This condition, characterized by blackened or mushy spots on the bottom of the tomatoes, is usually caused by a calcium deficiency. To prevent this, make sure that the soil has adequate calcium and is not waterlogged.

Pests: Tomatoes are susceptible to a variety of pests, such as aphids and caterpillars. Keep an eye out for any signs of infestation and treat them promptly with organic pesticides or insecticidal soap.

With a little bit of planning and care, you can enjoy a bountiful harvest of tomatoes in southern Arizona. Remember to choose the right time to plant, select a suitable location, and provide proper care and maintenance.