tomato sprouts

When to Plant Tomatoes in Zone 12

USDA hardiness zone 12 is characterized by a tropical climate, with hot and humid conditions. The high temperatures can exceed 100°F (38°C) during the day. Tomatoes require abundant heat and water to thrive but in this zone, the elements can be too excessive for tomatoes. To successfully grow tomatoes in zone 12, it is important to choose tomato varieties that can tolerate extreme heat, provide ample shade to the plants, and use appropriate cultural practices such as proper irrigation and pest management. Cover crops and companion plants can help to protect and shield tomato plants from unwanted elements. With proper planning and care, it is possible to have a successful tomato crop in the USDA hardiness zone 12.

USDA Hardiness Zone 12 Climate

USDA hardiness zone 12 is a tropical zone that encompasses parts of southern Florida and Hawaii. It is characterized by high temperatures, with the average minimum temperature above 50°F (10°C) and the maximum temperature often exceeding 100°F (38°C). Growing tomatoes in zone 12 can be challenging due to the extreme tropical climate and extreme heat.

The high temperatures and humidity of zone 12 can cause the tomato fruit to develop sunscald, and blossom drops can also occur due to the hot temperatures. Heavy rainfall in this zone can lead to soil erosion, nutrient leaching, and the spread of diseases. To overcome these challenges, it is important to select tomato varieties that can tolerate extreme heat and humidity, provide ample shade to the plants, and use practices such as mulching and irrigation management. Companion plants can do much of the work for you protecting your tomato crops from the elements, pests, and soil erosion.

When to start tomatoes indoors in zone 12

If you want to get an early start on cultivating tomatoes, begin growing the seeds mid-winter when the average temperature is 60 degrees. The best-suited temperature ranges are from spring to fall.

You can even keep them in a large pot. This is a totally acceptable practice and can save you some future headaches with the elements. To start tomato seeds indoors:

  1. Select a planting container. Choose a container that is at least 6-8 inches deep, with holes in the bottom for drainage.
  2. Fill with a seed starter potting soil.
  3. Plant 2-3 tomato seeds ⅛ inch deep in the soil and cover.
  4. Water the soil until it is moist but not soggy.
  5. Place the container in a warm, sunny spot indoors and keep the soil moist.
  6. When the seedlings reach 2-3 inches tall, thin them out so there is only one seedling per container.

Tomato varieties that do well in zone 12

Growing early-harvest tomatoes is not essential in zone 12, due to the longer growing season (8 to 17 weeks). It is still a worthy practice to protect your plants from surprise freezes and to maximize your season. Some varieties of tomatoes are ready to harvest in under 60 days, so you could double up a harvest if the conditions are right. You have more options in zone 12, so feel free to try a few long-harvest varieties, such as the ones below:

  1. ‘Aunt Gertie’s Gold’ Tomato – 75-80 Days to Harvest
  2. ‘Heidi’ Tomato – 90 Days to Harvest
  3. ‘Opalka’ Tomato – 90 Days to Harvest
  4. ‘Martino’s Roma’ Tomato – 70-80 Days to Harvest
  5. ‘Cherokee Purple’ Tomato – 80 Days to Harvest
  6. ‘Brandywine’ Tomato – 80-100 Days to Harvest
  7. ‘Tidwell German’ Tomato – 80 Days to Harvest
  8. ‘Celebrity’ Tomato – 70 Days to Harvest
  9. ‘Chapman’ Tomato – 80 Days to Harvest
  10. ‘Gardener’s Delight Tomato – 65 Days to Harvests

Hardening off your tomatoes

Hardening off tomatoes that you’ve started indoors before planting outdoors is important to ensure they can thrive in the outdoor environment. When tomatoes are started indoors, they become accustomed to the warm and more stable environment. When planted outdoors, they are exposed to more extreme temperatures, wind, and sun. Hardening off tomatoes helps them slowly adjust to their new environment by exposing them to these elements for an extended period.

The process of hardening off tomatoes begins by slowly introducing them to the outdoors. Start by placing them in a sheltered spot, such as a porch or a partially shaded area, for a few hours each day. Over a week, gradually increase the amount of time they are kept outdoors and the amount of sun they are exposed to. After a week of hardening off, the tomatoes should be ready to move to their final outdoor planting location.

When to plant tomatoes in zone 12

It’s generally safe to plant tomatoes outdoors when there is no risk of frost or freezing temperatures. In most climates, this means waiting until at least late spring or early summer. In zone 12, there is no expected frost date. Tomatoes can be planted as early as mid-winter but for best results wait until spring to fall. Still, be mindful of your weather forecast. Keeping an eye out for heat waves and constant rain will help you plan.

When to harvest tomatoes in zone 12

When tomatoes have turned a deep red (or the ripe color of their particular variety) and have no green spots visible, they are ripe and ready to be picked. If there are still green patches on the tomato, it has not yet ripened and should remain on the vine. The ideal way to pick ripe tomatoes is to cup the tomato in your hand and give it a gentle twist- it should come off the vine with ease. When in doubt, you can leave it on the vine an extra couple of days, or harvest the entire branch of tomatoes and allow it to ripen on the vine on your window sill.

Jeff Grayson
Garden Hobbyist
Hello! I'm Jeff, an avid gardening enthusiast. I'm based out of Colorado, where I raise as many indoor and outdoor plants as I can!