Sun Gold Tomato in Zone 7B — Desert Southwest

Sun Gold Tomato is practically synonymous with "delicious" for a reason, and it's a rewarding choice for the Desert Southwest garden. Their intense sweetness and easy snacking size make them irresistible straight from the vine, plus they are versatile enough for everything from salads to sauces. Successfully growing these gems here is totally doable with a little planning.

Our extreme heat, alkaline soil, and monsoon season can present challenges, but our long growing season (around 245 days) gives you two opportunities to grow these tomatoes: a spring crop and an extended fall harvest. Careful timing is key.

Starting your Sun Gold Tomato seeds indoors gives you a head start in our very-early spring. Begin your seeds indoors from early February through early March, about six weeks before you plan to transplant them outside. This gets them going before the worst of the summer heat arrives.

Use seed trays or small pots filled with a good seed-starting mix. Keep the soil consistently moist (but not soggy) – bottom watering works great to prevent damping off. Provide warmth (a heat mat helps) and plenty of light, either from a grow light or a very sunny window.

Remember, our spring weather can be unpredictable, so keeping your seedlings protected indoors during those early weeks is essential for success.

Transplant your Sun Gold Tomato seedlings outdoors from late March through late April. This gives them time to establish before our extreme heat kicks in. Before planting, harden off your seedlings by gradually exposing them to outdoor conditions for about a week.

Choose a sunny spot with well-draining soil. Space your plants 24-36 inches apart to give them plenty of room to grow. Even in late March and April, protect newly transplanted seedlings from sunburn with shade cloth during the hottest part of the day, especially if there's a temperature swing.

Sun Gold Tomatoes are thirsty plants, and consistent watering is critical for preventing fruit cracking in our arid climate. They need a lot of water. During our spring growing season, aim for at least 1-2 inches of water per week. As the summer heat intensifies, increase that to 2-3 inches per week, or even more during the hottest stretches.

The "finger test" is your friend: stick your finger about 2 inches deep into the soil. If it feels dry, it's time to water. Water deeply at the base of the plant to encourage strong root growth and avoid wetting the foliage, which can lead to disease in our occasional monsoon humidity. Signs of underwatering include wilting leaves and blossom end rot (a dark, sunken spot on the bottom of the fruit). Overwatering can lead to yellowing leaves and root rot.

Mulching around your tomato plants with straw or wood chips helps retain moisture in our dry air and keeps the soil cooler.

Sun Gold Tomatoes are vigorous indeterminate plants, meaning they'll keep growing and producing all season long. They need serious support. Cages or sturdy stakes are essential to keep the sprawling vines off the ground.

Install your chosen support system 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. These plants can get HUGE, so don't underestimate the need for strong support.

Pruning is essential for managing Sun Gold Tomatoes in our region. These plants are known for their aggressive growth, and they'll quickly take over your garden if left unchecked. Focus on removing suckers – the small shoots that grow in the "V" between the main stem and the branches. Pinch them off when they're small.

Also, prune away the lower leaves that touch the soil to improve air circulation and prevent disease. Continue pruning throughout the growing season to keep the plant manageable and encourage fruit production. As the first frost approaches in mid- November, you can top the plant to encourage the remaining green tomatoes to ripen.

Get ready for a flood of sweet, golden tomatoes! You can expect your first harvest from late May through mid-July, depending on when you transplanted. Sun Gold Tomatoes are ready to pick when they turn a deep orange-gold color, feel slightly soft to the touch, and practically fall off the vine.

Gently twist or snip the tomatoes from the plant, being careful not to damage the stems. The more you harvest, the more the plant will produce, so check your plants regularly. As the weather cools down in the fall, you can harvest any remaining green tomatoes and ripen them indoors in a paper bag.

Even with careful planning, you might encounter a few problems with Sun Gold Tomatoes in the Desert Southwest. The most common issues are cracking, over-production, and early blight.

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 or monsoon rain after a dry spell. The fruit absorbs water faster than the skin can expand.
• How to fix/prevent it: Water consistently and deeply. Mulch to maintain even soil moisture. Harvest promptly when ripe.

Over-production

• What it looks like: More tomatoes than you can possibly eat or give away! Plants are so loaded down that branches break.
• What causes it: Sun Golds are just prolific! Warm days and nights coupled with plenty of water and nutrients can lead to a bumper crop.
• How to fix/prevent it: Plan ahead for preserving (canning, freezing, drying). Share with neighbors. Pick frequently to encourage continued production, even if you can't use them all immediately.

Early Blight

• What it looks like: Brown spots with concentric rings (target or bullseye pattern) on lower leaves first, spreading upward. Leaves yellow and drop.
• What causes it: A fungal disease (Alternaria solani) that thrives in warm, humid conditions. Spreads via soil splash onto lower leaves.
• How to fix/prevent it: Remove and destroy affected leaves (don't compost). Mulch to prevent soil splash. Water at the base, not overhead. Improve air circulation through spacing and pruning. Copper fungicide can slow the spread.

Desert Southwest Specific Challenges: Our extreme heat can cause sunscald on the fruit, so providing some afternoon shade with shade cloth can be helpful. Low humidity can stress the plants, making consistent watering even more critical. The monsoon season can bring sudden downpours that lead to cracking, so be prepared to harvest ripe tomatoes quickly when rain is in the forecast.

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

Good companions include basil, which repels tomato hornworms and other pests; carrots, which loosen the soil and improve drainage; parsley, which attracts beneficial insects; and French marigolds, which deter nematodes.

Avoid planting brassicas (like cabbage and broccoli) near your tomatoes, as they compete for nutrients. Fennel inhibits the growth of many plants, including tomatoes. Corn can attract pests that also affect tomatoes.