When to Plant Tomatoes in Indiana

Growing tomatoes in Indiana is a rewarding experience. It requires careful attention to the changing weather patterns throughout the season. Indiana’s variable climate, with hot and humid summers and cold winters, presents unique challenges to tomato growers. Overall, growing tomatoes in Indiana requires patience, dedication, and a willingness to adapt to the weather conditions.

Tomatoes in Indiana’s Climate

Indiana has a continental climate with four distinct seasons. Summers tend to be hot and humid, while winters are cold and snowy. The state experiences a moderate amount of rainfall throughout the year, with slightly more precipitation during the spring and summer months.

The climate in Indiana has everything that tomatoes need to thrive, but there are elements that can hinder growth. Hot and humid summers can lead to an increase in pests and diseases, such as tomato blight and spider mites.

This can be mitigated by planting disease-resistant tomato varieties, providing adequate ventilation to reduce humidity levels, and using organic pest control methods like neem oil and insecticidal soap. Additionally, the fluctuating temperatures during spring and fall can stunt the growth of tomato plants or cause them to drop their blossoms.

This can be addressed by covering plants with frost blankets during cold snaps or planting tomatoes in raised beds with good drainage to prevent root rot. Consider companion planting with your tomatoes to mitigate many of these issues while maximizing your growing season and garden space.

When to Start Tomatoes Indoors in Indiana

If you want to get an early start on cultivating tomatoes, begin growing the seeds indoors 4-6 weeks before the final spring frost in your area, regardless of the tomato variety you’re growing. In Indiana, start sowing your tomato seeds indoors around March 10th, to March 26th, depending on where you live.

You may want to get them going even earlier than that and plant them in a large pot ahead of producing them outdoors, just to give them even more of a head start. To start tomato seeds indoors:

1. Select a planting container. Choose a container 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 Indiana

Growing early-harvest tomatoes can be very handy in Indiana, due to the diversity of its climate. Some varieties of tomatoes are ready to harvest in 60 to 100 days, which makes them perfect for the different zones in Indiana. Sow your seeds indoors to maximize your growing season’s yield. I recommend one of the following varieties: 

1. ‘Aunt Gertie’s Gold’ Tomato – 75-80 Days to Harvest
2. ‘Early Girl’ Tomato – 55 Days to Harvest
3. ‘Sun Gold’ Tomato – 55 Days to Harvest’Martino’s Roma’ Tomato – 70-80 Days to Harvest
4. ‘Fourth of July’ Tomato – 49 Days to Harvest
5. ‘Sweet Million’ Tomato – 45 Days to Harvest
6. ‘Oregon Spring’ Tomato – 50 Days to Harvest
7. ‘Celebrity’ Tomato – 70 Days to Harvest
8. ‘Yellow Pear’ Tomato – 60 Days to Harvest
9. ‘Gardener’s Delight Tomato – 52 Days to Harvests

Hardening Off Your Tomatoes

Hardening off tomatoes that you’ve started indoors before planting outdoors is essential 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 Indiana

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 Indiana, your final freeze date is expected around April 20th to April 30th depending on where you live. Still, be mindful of your weather forecast. If it seems like you’re in for a late freeze, wait to plant your tomatoes! 

When to Harvest Tomatoes in Indiana

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.