There are good tomato varieties to handle almost any growing situation, even in harsh climates, short growing seasons or limited space. Most tomatoes prefer temperatures between 70 and 85 degrees F to set fruit. Varieties developed in the southern U.S., Central and South America will perform better in hot weather, and those developed in very cold regions like Siberia will outperform others in cold conditions. Avoid genetically modified (GM) and hybrid varieties if you want to save seed for future crops.
Best Heat Tolerant Tomatoes
A red, plum-shaped indeterminate variety from Texas, "Porter" is a good choice for a sweet canning tomato that does not crack or sunburn in the hottest and most humid climates.
Great White Beefsteak is a productive and large white tomato with extreme heat tolerance and mild flavor.
Pink Accordian, Purple Calabash, Ponderosa Pink, Tennessee Green, Homestead 24 and Super Sioux are other good open-pollinated (non-hybrid) varieties for hot areas. All but Homestead 24 are indeterminate varieties.
Heat tolerant hybrids include Solar Set, Sunmaster, Solar Fire, Sannibel and Heatwave II. All are determinate varieties with heavy fruit sets.
Flavor is literally a matter of taste, but there is some general agreement in the world of tomato aficionados that Brandywine is near the top.
Caspian Pink, an old-fashioned Russian ruffled variety, is another contender. Among the more obscure varieties, the "black" heirloom Cherokee Purple (true tomato taste with a hint of smoke) is a popular choice, along with Omar's Lebanese, Black Cherry, Pork Chop and Isis Candy.
Of hybrid varieties, only Sungold systematically ranks with heirloom varieties as among the best in taste tastes.
Best Cold-tolerant Tomatoes
Siberian, which is capable of setting fruit at 38 degrees F, and Manitoba are two great early and cold tolerant varieties. Both are determinant, heavy producers. Plants put their energy into fruiting and because of that remain short and robust.
The Alaska bred Polar varieties, Polar Baby, Polar Star and Polar Beauty, are also good cold-weather varieties. Others include Sub-Arctic Plenty, which may be one of the earliest at 42 to 48 days, Glacier and Stupice. The last two also are noted for their superior flavor.
A Canadian variety called Cold Set was developed to be directly sown in the garden at temperatures as low as 18 degrees F. It is also determinant.
Best Small Space Tomatoes
Determinant varieties tend to work best for small-space gardens because they bush rather than produce long vines, but growing tomatoes from hanging baskets or up a trellis vertically will free up space and give more freedom of choice in varieties. Cherry tomatoes such as Sungold and Black Cherry have already been mentioned for superior flavor, but they also make excellent patio or container plants. Another excellent choice is Riesentraube (German for "bunch of grapes"), which is extremely productive and provides real value where you may only have room for one tomato. For tomato paste try red or yellow Pear, or grow Green Grape for making green ketchup.