Sun Gold Tomato in Zone 7A — Desert Southwest

Sun Gold tomatoes are a desert gardener's dream. Their intensely sweet flavor and prolific yields make them perfect for snacking straight from the vine, adding to salads, or even grilling. Plus, the satisfaction of harvesting baskets of these golden gems in our two growing seasons is hard to beat.

Yes, our extreme heat and arid conditions present challenges, but with careful timing and smart gardening practices, you can successfully grow Sun Gold tomatoes in the Desert Southwest. Our long 230-day growing season gives you ample opportunity to enjoy these delicious fruits.

Starting your Sun Gold tomato seeds indoors is the way to go in our climate. Begin in mid February through mid March, roughly six weeks before you plan to transplant them outside. This head start is crucial, given our very-early spring character.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist, but not soggy. Bottom watering is your friend here – set the trays in a shallow dish of water and let the soil absorb it from the bottom. Place the trays in a warm location (around 70-75°F) and provide plenty of light, either from a sunny window or a grow light.

Transplant your Sun Gold tomato seedlings outdoors in early April through early May, after the danger of frost has passed. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week. This will help them adjust to the intense Desert Southwest sun and wind.

Space your plants 24-36 inches apart to allow for their vigorous growth. Keep an eye on the weather forecast – even in early April, we can still get some surprising temperature swings. Protect your young plants from any late frosts with row covers or blankets.

Sun Gold tomatoes are thirsty plants, and consistent watering is key to preventing fruit cracking in our arid climate. During the hottest part of the summer, you'll likely need to water deeply every other day, or even daily, especially if they're in containers. The "finger test" is a reliable way to check: stick your finger into the soil about 2 inches deep. If it feels dry, it's time to water.

Aim for about 1-2 inches of water per week, delivered at the base of the plant to avoid wetting the foliage. Given our low humidity, overhead watering isn't as risky as it is in more humid climates, but still try to focus on the roots. Underwatering can lead to blossom end rot and cracked fruit, while overwatering can cause root rot, so pay attention to your plants' cues.

Signs of underwatering include wilting leaves and dry soil. Overwatering can manifest as yellowing leaves and soggy soil. Mulching around your tomato plants with straw or wood chips helps retain moisture in the soil and regulate soil temperature, which is particularly important in our extreme heat.

Sun Gold tomatoes are known for their vigorous, indeterminate growth habit, so providing strong support is essential. A tall, sturdy tomato cage is often the easiest option, but staking is also effective. This variety will quickly outgrow smaller, flimsy supports.

Install your chosen support at planting time to avoid disturbing the roots later. As the plant grows, gently weave the stems through the cage or tie them to the stake with soft twine. Check the supports regularly and reinforce them as needed, especially as the plant becomes laden with fruit.

Sun Gold tomatoes are prolific growers and will quickly take over your garden if left unpruned. Regular pruning of suckers (the small shoots that grow in the "V" between the main stem and branches) is crucial to maintain manageable growth and improve air circulation.

Focus on removing suckers from the bottom of the plant upwards, leaving the main stem and fruiting branches intact. Prune early in the morning on a dry day to minimize the risk of disease. As the end of the season approaches (around early November), you can top the plant to encourage the remaining green tomatoes to ripen before the first frost.

You can expect your first harvest of Sun Gold tomatoes in early June through late July, about 57 days after transplanting. The tomatoes are ripe when they turn a vibrant orange-gold color and are slightly soft to the touch. They should also have an intensely sweet aroma.

The easiest way to harvest is to gently twist the tomato until it separates from the vine. Be careful not to damage the plant or surrounding fruit. To encourage continued production, harvest regularly and remove any overripe or damaged fruit. As the first frost approaches in early November, harvest any remaining green tomatoes and bring them indoors to ripen. They will ripen best in a single layer, not touching, in a cool, dark location.

Here are three common problems you might encounter with Sun Gold tomatoes in the Desert Southwest:

Cracking

• What it looks like: Splits in the tomato skin, either concentric circles around the stem or radial lines radiating from the stem.
• What causes it: Inconsistent watering, especially heavy watering after a dry spell. Our monsoon season can exacerbate this issue.
• How to fix/prevent it: Water consistently to maintain even soil moisture. Mulch around the plants to help regulate soil temperature and moisture levels. Harvest ripe tomatoes promptly.

Over-Production

• What it looks like: An overwhelming abundance of tomatoes, often more than you can use.
• What causes it: Sun Golds are inherently prolific, and our long growing season allows for extended fruiting.
• How to fix/prevent it: Plant fewer plants, succession plant, and get creative with using and preserving your harvest. Share with neighbors! Consider canning, freezing, or making sauces.

Early Blight

• What it looks like: Brown spots with concentric rings (target or bullseye pattern) on lower leaves, spreading upward. Leaves yellow and drop.
• What causes it: A fungal disease (Alternaria solani) that thrives in warm conditions and spreads via soil splash.
• How to fix/prevent it: Remove and destroy affected leaves. Mulch to prevent soil splash. Water at the base of the plant. Improve air circulation through spacing and pruning. Copper fungicide can help slow the spread. Rotate crops yearly.

Desert Southwest Specific Challenges: The extreme heat can cause sunscald on the fruit, so providing some afternoon shade with shade cloth can be beneficial. Our arid conditions can also stress the plants, making them more susceptible to pests and diseases. Consistent watering and proper soil management are essential for success.

Companion planting can help your Sun Gold tomatoes thrive in the Desert Southwest.

Good companions include basil, which repels tomato hornworms and improves tomato flavor. Carrots loosen the soil and deter nematodes. Parsley attracts beneficial insects. French marigolds repel nematodes and other pests. All these companions benefit from similar watering needs as tomatoes.

Avoid planting brassicas (cabbage, broccoli, cauliflower) near tomatoes, as they compete for nutrients. Fennel inhibits the growth of many plants, including tomatoes. Corn can attract tomato pests like corn earworms. Keep your tomatoes away from these plants to ensure a healthy harvest.