tomato seedlings

When To Plant Tomatoes In Zone 3

Growing tomatoes in zone 3 can be quite challenging due to the shorter growing season and harsher winters. The cooler temperatures in zone 3 mean that tomatoes will need to be planted later in the season, usually around May 15th, and harvested before the first frost in September. Tomatoes also need plenty of sun and heat, which can be hard to come by in the northern climates of zone 3. Gardeners in zone 3 may need to invest in a shoter-season variety of tomatoes. With some careful planning and protection, growing tomatoes in zone 3 can be a rewarding experience.

USDA Hardiness Zone 3 Climate

USDA Hardiness Zone 3 has a climate that is well-suited for growing shorter-season tomatoes. The final frost of the year typically occurs around May 15th, making it possible to start planting tomatoes after that date.

Tomatoes grown in Zone 3 can typically be harvested from late summer through late fall. Early varieties, such as cherry tomatoes, can be harvested in June, and larger slicing tomatoes can be harvested in late August to early September before frost sets in. It is important to keep an eye on the weather, however, as late frosts can threaten tomato plants. If frost is forecasted, it may be necessary to cover the plants with blankets or other protective materials.

When to start tomatoes indoors in zone 3

If you want to get an early start on cultivating tomatoes, begin growing the seeds indoors 4-6 weeks prior to the final spring frost in your area, regardless of the tomato variety you’re growing. In zone 3, you’ll want to start your tomato plants indoors around April 1st.

You may want to get them going even earlier than that and plant them in a large pot ahead of planting 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 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 3

Growing early-harvest tomatoes is essential in zone3, due to the shortened growing season. Some varieties of tomatoes are ready to harvest in under 60 days, which is ideal in the short growing season of zone 3. I recommend one of the following varieties: 

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

Hardening off your tomatoes

Hardening off tomatoes that you’ve started indoors before planting outdoors is important to ensure they are able to 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 of time.

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 the course of 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 3

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 3, your final freeze date is around June 4th, but 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 zone 3

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 to ripen on the vine on your window sill.

Thomas Nelson
Gardening Expert
Hi! I'm Thomas, one of the founders of The Garden Magazine. I come from a long line of gardeners who used the art of gardening as a way to live long, healthy lives. I'm here to share my knowledge of gardening with the world!