Sun Gold Tomato in Zone 9B — Southern California

Sun Gold tomatoes are like sunshine in your mouth, and they thrive in our Southern California climate. Their sweet, tangy flavor makes them perfect for snacking straight from the vine, adding to salads, or even grilling. Plus, the sheer volume of these golden gems you'll harvest is incredibly rewarding.

Sure, SoCal throws us some curveballs like drought and the occasional heat wave, but with a little planning, you can enjoy a bumper crop of Sun Golds. Our long growing season (around 334 days!) gives you plenty of time to get these tomatoes from seed to table, so let's get started!

To get a jump start on your tomato season, start your Sun Gold seeds indoors from late December through mid January, about six weeks before you plan to transplant them outside. Use seed trays or small pots filled with a good seed-starting mix. Keep them warm – a heat mat helps – and provide plenty of light with a grow light or a sunny windowsill facing south.

Bottom watering is a great way to keep the soil consistently moist without disturbing the delicate seedlings. Just pour water into the tray beneath the pots and let the soil soak it up. Remember, spring comes early here in Southern California, so getting a head start indoors is key.

Transplant your Sun Gold seedlings outdoors from early February through early March, once the danger of frost has passed. Before you move them permanently, harden them off by gradually exposing them to outdoor conditions for about a week. Start with an hour or two of shade and slowly increase the time and sun exposure each day.

Plant them 24-36 inches apart in well-drained soil amended with compost. Keep an eye on the weather forecast – even in early spring, we can get unexpected temperature swings, so be ready to cover your seedlings if needed.

Sun Golds are thirsty plants, especially when they're loaded with fruit, and consistent watering is crucial in our Southern California climate. During the warmer months, especially inland where we get that extreme summer heat, you'll likely need to water deeply several times a week. Stick your finger about two inches deep into the soil; if it feels dry, it's time to water.

Aim for about 1-2 inches of water per week, depending on the weather. Water at the base of the plant to avoid wetting the leaves, which can encourage fungal diseases in our occasionally humid conditions. Signs of underwatering include wilting leaves and blossom end rot, while overwatering can lead to yellowing leaves and root rot.

A good layer of mulch around your plants will help retain moisture and keep the soil cool during those hot summer months. Remember, our water restrictions mean we need to be extra mindful of water conservation!

Sun Gold tomatoes are vigorous growers, so they need strong support. Cages or sturdy stakes work well, but since these plants get BIG, I recommend tall, heavy-duty cages. Install the support at planting time to avoid damaging the roots later.

As the plant grows, gently guide the stems through the cage or tie them to the stake with soft twine. This will help keep the plant upright and prevent the fruit from touching the ground.

Sun Golds are known for their sprawling growth habit, so pruning is essential to keep them manageable and productive. Focus on removing suckers, which are the small shoots that grow between the main stem and the branches. These suckers will steal energy from the plant and reduce fruit production.

Prune regularly throughout the growing season, especially after fruit sets. As the end of our growing season approaches (late December), you can top the plant to encourage the remaining green tomatoes to ripen before any potential frost.

Get ready for a bountiful harvest of sweet, golden tomatoes from early April through late May! Sun Golds are usually ready to pick about 57 days after transplanting. The best indicator of ripeness is their deep orange-gold color and slightly soft texture. They'll also develop an intensely sweet aroma.

Gently twist or clip the tomatoes from the vine, being careful not to damage the plant. To encourage continued production, harvest regularly as the fruits ripen. As the first frost approaches in late December, harvest any remaining green tomatoes and bring them indoors to ripen.

Here are three common problems you might encounter with Sun Gold tomatoes in Southern California:

Cracking

• What it looks like: Splits in the tomato skin, either in circles around the stem or lines radiating from it.
• What causes it: Inconsistent watering, especially heavy watering after a dry spell. The fruit absorbs water too quickly, and the skin can't keep up. This is more common after our winter rains.
• How to fix/prevent it: Water consistently and deeply, especially during dry periods. Mulch around the plants to help maintain even soil moisture. Harvest ripe tomatoes promptly to prevent them from cracking further.

Over-Production

• What it looks like: A massive amount of tomatoes all ripening at once, more than you can possibly use.
• What causes it: Sun Golds are just naturally prolific! This can be exacerbated by our long growing season and abundant sunshine.
• How to fix/prevent it: Plan ahead! Share with neighbors, preserve by canning or freezing, or make large batches of sauce. You can also succession plant, starting new seedlings a few weeks after the first batch, to spread out the harvest.

Early Blight

• What it looks like: Brown spots with concentric rings (a target pattern) on the lower leaves, which then yellow and drop off. The disease spreads upward.
• What causes it: A fungal disease that thrives in warm, humid conditions. It's spread by soil splashing onto the leaves, especially during our winter rains.
• How to fix/prevent it: Remove and destroy affected leaves immediately. Mulch well to prevent soil splash. Water at the base of the plant, not overhead. Improve air circulation by pruning. Copper fungicide can help slow the spread if the infection is severe.

Southern California Specific Challenges: Our hot summers can stress tomato plants, making them more susceptible to diseases. The low-to-moderate humidity can actually be a benefit, reducing the risk of some fungal issues, but consistent watering is key to prevent cracking and blossom end rot, especially during drought conditions. Be prepared for Santa Ana winds, which can quickly dry out plants and increase the risk of cracking.

Companion planting can help your Sun Gold tomatoes thrive. Basil is a great companion because it repels many common tomato pests and is said to improve the flavor of the tomatoes. Carrots and parsley attract beneficial insects that prey on tomato pests. French marigolds deter nematodes and other soil-borne pests.

Avoid planting brassicas (like broccoli and cabbage) near your tomatoes, as they can stunt their growth. Fennel inhibits the growth of many plants, including tomatoes. Corn can attract tomato hornworms, which can quickly defoliate your plants.