OK, I want to test tomatoes but how Do I Know What To Start With?
Ah, now there’s the problem.
If you live in the north and have a short growing season, look for varieties that are shorter day length or “growing degree days”
A “day length” isn’t related to the actual day, it’s a measure of the amount of sunlight a plant requires. So if you grow a 72 day tomato, it doesn’t mean you’ll get fruit in 72 days. It means you’ll get fruit whenever your area generates enough light to equal the standard of perfect light for 72 days.
If you have a cloudy, rainy season, your 72 day tomato could very well wind up taking 85 days (or more) to give you fruit.
So – the colder your garden, the shorter day-length you want to grow. A zone 4 garden will get fruit from a 72-day tomato in almost every year. But an 80-day tomato is going to require some extra time to mature.
Heirloom tomatoes are not usually measured this way – what you’ll get is (hopefully) a rating of “early”, “mid-season” or “late”.
What I’d Start With
I’d start with at least one (but preferably 3 plants) of each – early, mid and late (and toss in 2 cherry tomato varieties) giving you about a dozen tomatoes. That will quickly give you the range of fruit for your area. And then start fine-tuning for taste and production under your individual garden skills and soil/temperature etc.
For example. We were given a ‘Mayo’s Delight’ that was supposed to be a later season tomato to discover in our garden it was a mid-season harvest. And it was a big, red, solid fruit. The fact it was named after my partner was irrelevant. (But nice to have it happen that way) Similarly, a ‘Golden Siberian’ turned out to not be overly early but large, lovely and mid-season.
I’d Keep Notes
I’d keep notes (because my memory is a little fuzzy) and rank each variety for taste, yield, disease resistance or any other criteria that’s important to you. Rank each plant on a scale of 1-10 and don’t worry about accuracy. Just rank them against each other. The best tasting tomato gets a 10. Next gets an 8 etc etc for all criteria.
After Three Years
Do this for three years. After year three, the lowest ranked tomato is no longer grown. Add another variety and test it.
After a few years, you’re going to find you have tomatoes that you enjoy eating and that grow well for you.
If you want to read about “Growing Degree Days”