When to Plant Tomatoes

An important temperature to remember: tomatoes can be planted in the garden when the soil temperature reaches 60 degrees Fahrenheit. You can buy a soil thermometer to get an accurate reading, or you can guess the soil temperature by placing your finger the soil. If you’re the kind of gardener that keeps records, make note of the date and soil temperature for future plantings.

Another temperature to keep in mind: tomato plants will not survive in temperatures below 35 degrees Fahrenheit, and will not thrive at temperatures below 50 degrees. Gardeners can use a frost date calendar to note their region’s average dates of last frost in spring and first frost in fall.

This is the minimum for plant survival. The temperatures at which tomatoes thrive are between 55 and 85 degrees Fahrenheit.

Check plant tags for information on the varieties you plant, but by and large, tomatoes will not set fruit when temps hit 85 degrees, and may have trouble setting color in the heat. Starting tomatoes early gives the plant time to set fruit before the hottest days of summer. The heat will help the fruit grow.

Heat-loving tomato plants, along with peppers, need 8 to 12 weeks from seed to the garden.

To get started, check seed packets for the number of days for germination and to maturity, then work with your region's average date of last frost in spring to determine how early to start your seeds.

It's easy to start tomatoes (and other vegetables and flowers) from seeds with some inexpensive materials. Learn more about starting your garden with seeds.

Once the ground warms to 60 degrees Fahrenheit, you can plant your seedlings in the ground. To get the earliest fruit in your garden, you can buy a few nursery grown tomato plants with flowers or fruit already on them to plant alongside.

In late summer, you have another window to plant tomatoes to get a crop in before the first frost in your area. Keep in mind that fall crops grow differently than spring ones. The days are getting shorter and the sun is lower in the sky, so it will take longer for the fruit to ripen.

When planting in summer, select varieties adapted for warm climates with strong stems and lots of flowers. Choose varieties that mature quickly, such as ‘Sungold’ cherry, ‘Better Boy’ and ‘Celebrity,’ which all mature in less than 70 days.

You may be surprised to find a bigger harvest in the fall, since the plants have escaped attacks from spring pests and diseases, and the weather is often
rainier.

Now that you know when to grow tomatoes, here's how to plant them in your garden.

• Select early varieties adapted for warm climates with strong stems and lots of flowers.
• Plant in an area that gets at least 6 hours of sun a day.
• Space plants at least 2 inches apart. Check plant labels; some varieties may require more space.
• Dig a hole 6 to 8 inches deep and 6 to 8 inches wide for each seedling.
• Fill the hole with 3 inches of compost mixed with a handful of organic tomato fertilizer.
• Remove the bottom leaves on each plant, leaving only two sets of leaves at the top.
• Place the plant in the hole and fill with soil up to the remaining set of leaves. Push dirt against the stem to prop it up.
• Cover area around roots with an inch-thick layer of mulch.
• Keep water off lower leaves to prevent disease. Tomatoes need a couple inches of water per week.
• Stake or cage each plant, pushing the support firmly into the soil.