I have been growing heirloom tomatoes on Saginaw Bay for years, and every season refines the list of what works. Michigan Zone 6a is not the easiest place to grow indeterminate heirloom tomatoes—our season is short, our humidity is high, and our patience is tested—but the rewards are worth every bit of effort.
Here are the heirloom tomato varieties that have earned a permanent place in my garden at Freighter View Farms in Bay City, Michigan.
Brandywine
The queen of heirloom tomatoes, and for good reason. Brandywine produces large, pink-red fruit with a complex, sweet flavor that no hybrid can match. In my Zone 6a garden, it matures in about 80 to 85 days from transplant. The plants are vigorous—I grow them as single-stem plants, pruning aggressively and staking to seven feet. The first ripe Brandywine of the season, sliced thick and eaten with nothing but salt and a piece of bread, is the reason I garden.
Cherokee Purple
Dusky, dark, and deeply flavored. Cherokee Purple is my second-favorite slicer. It matures slightly earlier than Brandywine—around 75 to 80 days—which makes it a safer bet for our short Michigan season. The color alone, that dark purple-brown with green shoulders, makes it worth growing.
Mortgage Lifter
If you want massive fruit and plenty of it, Mortgage Lifter delivers. This variety produces beefsteak-size tomatoes—often over a pound each—with a mild, sweet flavor. It is slightly more disease-resistant than Brandywine, which matters in our humid Saginaw Bay summers.
Sun Gold
The best cherry tomato ever bred. Sun Gold produces an almost absurd quantity of small, orange, candy-sweet fruit from July until hard frost. It is technically a hybrid, not an heirloom, but it has earned its place in my garden by sheer force of productivity and flavor. Children and adults alike cannot walk past the plant without eating half a dozen.
Costoluto Fiorentino
An Italian heirloom with deeply ribbed, flattened fruit. Costoluto is a sauce tomato—meaty, acidic, and intensely flavored. It makes the best tomato sauce I have ever tasted. In my Michigan garden, it matures around 80 days and handles humidity reasonably well with good pruning and air circulation.
Growing Tips for Michigan
Heirloom tomatoes in Zone 6a need every advantage you can give them. Start seeds indoors under grow lights in mid-March. Transplant after mid-May when soil has warmed. Use black plastic mulch to warm soil. Grow as single-stem, heavily pruned plants for best air circulation in our humid climate. Water at the base, never overhead. And save seeds from your best performers—every generation gets a little more adapted to your specific garden.
For the full tomato story, read Searching for the Perfect Slicing Tomato Seed. For seed saving techniques, see the Complete Guide to Seed Saving for Beginners.
You Might Also Enjoy
A Year in the Garden: Chris Izworski’s 2025 Season at Freighter View Farms
What to Plant in February in Michigan: A Zone 6a Garden Guide | Chris Izworski
— Chris Izworski, Freighter View Farms, Bay City, Michigan
Freighter View Farms | Chris Izworski 
Leave a reply to Why I Write About Artificial Intelligence and Gardening in the Same Place – Freighter View Farms | Chris Izworski Cancel reply