When to Plant Tomatoes in Minnesota: A Gardener’s Guide

Posted on Category:When to plant
Tomatoes started mid March in Minnesota

Optimizing the Start of Your Tomato Season Using Grow Bags in Minnesota

Knowing when to plant tomatoes in Minnesota is critical to the success of your tomato plants. The window for frost-free gardening is narrow. Using grow bags offers flexibility and extends the growing season slightly due to their ability to warm up quicker than the ground. This guide focuses on when to start your tomatoes in grow bags and how to manage them throughout the growing season to maximize your harvest.

when to plant tomatoes in Minnesota

1. Understanding Minnesota’s Growing Climate

In Minnesota, where the growing season is squeezed between the last frost in late May and the first frost in mid-September, every day counts. Grow bags can be particularly advantageous here as they can be moved to avoid late spring frosts or early autumn chills.

2. The Advantages of Grow Bags for Early Starts

Grow bags heat up faster than soil in the ground, allowing for earlier planting and extended growing at the season’s edges. This feature is particularly beneficial in Minnesota, enabling gardeners to jump-start the season even when the ground is still too cold for planting.

3. Starting Seeds Indoors

To make the most of the growing season, start your tomato seeds indoors about 6-8 weeks before the expected last frost date. For most areas in Minnesota, this means starting your seeds in late March to early April. The early start is crucial for developing strong seedlings ready for transplanting as soon as the weather allows.

4. Selecting the Right Tomato Varieties

Choose varieties that are known for their shorter growing periods. Varieties such as ‘Early Girl’, ‘Siberian’, and ‘Litt’l Bites’ are ideal for Minnesota’s climate, as they can mature faster and are more likely to produce a full crop before the first frost.

5. Hardening Off Tomato Seedlings

Before moving your tomato seedlings from indoors to grow bags, they need to be hardened off. Begin this process around two weeks before you plan to transplant, gradually exposing the seedlings to outdoor conditions to strengthen them.

6. Transplanting into Grow Bags

Transplant your hardened-off tomato seedlings into grow bags after the danger of the last frost has passed, typically late May in Minnesota. Ensure your grow bags are filled with a rich, well-draining potting mix to support the nutritional needs of your growing plants.

7. Strategic Placement of Grow Bags

Position your grow bags in a spot that receives full sun for at least 6-8 hours per day. The portability of grow bags is beneficial for optimizing sun exposure and protecting plants from unexpected late frosts by moving them indoors or to sheltered locations if needed.

8. Regular Watering and Nutrition

Tomatoes in grow bags require diligent watering since the containers can dry out quickly. Implement a consistent watering schedule, and adjust based on rainfall and temperature changes. Feed your tomatoes with a balanced, slow-release fertilizer to ensure they receive all necessary nutrients for growth.

9. Staking and Support

Even in grow bags, tomato plants can become top-heavy and require support. Use stakes or cages within the bags to keep plants upright and promote healthier growth and air circulation.

10. Monitoring Growth and Adjusting Care

As your tomatoes grow, keep a close eye on plant health and growth progress. Adjust care as needed in response to weather changes, pest activity, or disease signs. Begin harvesting as soon as tomatoes ripen, usually starting in late July and continuing until the first frost.


In Minnesota, timing your tomato planting correctly and choosing grow bags as your cultivation method can significantly impact your gardening success. By starting seeds indoors, monitoring the weather for the optimal transplant time, and using grow bags for flexibility, you can maximize your tomato growing season despite the state’s short growing period. With careful planning and attentive care, you can enjoy a plentiful tomato harvest from your grow bags this season.