Sun Gold Tomato in Zone 9B — Desert Southwest

Sun Gold tomatoes are practically candy, and in our Desert Southwest gardens, they're a rewarding challenge. That burst of sweetness is worth the effort, and their prolific nature means you'll be sharing handfuls with neighbors. These little gems are fantastic in salads, roasted, or just popped straight into your mouth while you're weeding.

Sure, our extreme heat and alkaline soil can be tough on tomatoes. But with careful timing and a few desert gardening tricks, you can harvest buckets of these golden beauties. Our long, 313-day growing season gives us two chances to get it right, so don't be intimidated!

Start your Sun Gold tomato seeds indoors in early to late January to get a jump on the season. This gives them a head start before the extreme heat arrives. You have about a 3-week window to get this done.

Use seed trays with a good seed-starting mix and keep them warm – around 70-75°F is ideal. A heat mat can really help, especially with our cool desert nights. Give them plenty of light, either with a grow light or a very sunny windowsill. Bottom watering is key to avoid damping off. Since spring arrives very early here, you want strong seedlings ready to go in the ground as soon as possible.

Transplant your Sun Gold tomato seedlings outdoors from mid February through mid March. This timing allows them to establish before the worst of the summer heat. Before planting, harden them off by gradually exposing them to outdoor conditions for about a week.

Space them 24-36 inches apart. Remember, our desert sun is intense, so choose a spot with morning sun and some afternoon shade if possible. Keep an eye on the weather; even in late February, we can still get a surprise frost. Be ready to cover your seedlings if needed.

Sun Gold tomatoes are thirsty plants, especially in our arid Desert Southwest climate. Consistent watering is critical for preventing fruit cracking and ensuring a good harvest. During the spring growing season, water deeply 2-3 times per week, providing about 1-2 inches of water each time.

Stick your finger about 2 inches into the soil; if it feels dry, it's time to water. As the summer heat ramps up, you'll likely need to water daily, or even twice a day. Water at the base of the plant to avoid wetting the leaves, which can encourage fungal diseases in our monsoon season. Overhead watering can also lead to sunscald on the fruit.

Wilting leaves in the morning are a sign of underwatering, while yellowing leaves and soggy soil indicate overwatering. A good layer of mulch, like straw or wood chips, will help retain moisture and keep the soil cool.

Sun Gold tomatoes are vigorous indeterminate plants, meaning they'll keep growing and producing all season long. They need strong support to keep them off the ground and prevent the stems from breaking under the weight of the fruit. A tall, sturdy tomato cage is usually the best option.

Install the cage at planting time to avoid damaging the roots later. You can also use stakes, but you'll need to tie the plant to the stake every foot or so as it grows. These plants get HUGE, so don't underestimate the support they'll need.

Sun Gold tomatoes are notorious for their sprawling growth habit. If you don't prune them, they'll quickly take over your garden. Regular pruning is essential to keep them manageable and improve air circulation, which helps prevent diseases.

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, remove the lower leaves that touch the soil to prevent soilborne diseases from splashing onto the plant. As the end of the season approaches (around mid- December), you can top the plant to encourage the remaining fruit to ripen before frost.

You can usually start harvesting Sun Gold tomatoes from mid April through early June, depending on when you transplanted them. The tomatoes are ready to pick when they turn a vibrant orange-gold color and are slightly soft to the touch. The taste should be intensely sweet at this stage. Often, they'll even drop from the vine when they're perfectly ripe.

Gently twist or snip the tomatoes from the vine to avoid damaging the plant. To encourage continued production, harvest regularly. As the first frost approaches in mid- December, harvest any remaining green tomatoes and bring them indoors to ripen. They'll still taste great, even if they're not quite as sweet as vine-ripened ones.

Here are the top three 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. The fruit absorbs water faster than the skin can expand.
• How to fix/prevent it: Water consistently to avoid the dry/wet cycle. Mulch to maintain even moisture. Harvest promptly when ripe.

Over-production

• What it looks like: A massive amount of tomatoes all ripening at once, more than you can possibly eat or give away. Stressed plants might produce smaller, less flavorful fruit.
• What causes it: Sun Gold tomatoes are incredibly prolific. Our long growing season allows for continuous production.
• How to fix/prevent it: Succession planting can help even out the harvest. Stagger your planting dates to avoid a glut. Preserve the excess by canning, freezing, or making sauce.

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: Fungal disease (Alternaria solani) that thrives in warm, humid conditions. Spreads via soil splash onto lower leaves. Monsoon moisture can make this worse.
• 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 slows spread. Rotate crops yearly.

Desert Southwest Specific Challenges: Our extreme heat can stress tomato plants, making them more susceptible to diseases and pests. The arid climate can also lead to blossom end rot if watering is inconsistent. The monsoon season can bring periods of high humidity, which can exacerbate fungal diseases. Shade cloth is your friend.

Companion planting can help your Sun Gold tomatoes thrive in the Desert Southwest. Basil is a great companion because it repels tomato hornworms and other pests. Plus, it improves the flavor of the tomatoes. Carrots and parsley attract beneficial insects that prey on tomato pests. French marigolds deter nematodes and other soil pests.

Avoid planting brassicas (like cabbage and broccoli) near tomatoes, as they can stunt their growth. Fennel inhibits the growth of many plants, including tomatoes. Corn competes with tomatoes for nutrients and water, which is especially important in our water-scarce region.