The best way to get early tomato production is to plant as large a transplant as you can grown in as large a container as you can feasibly afford to do. We have growers in the piedmont area of NC who grow their plants for several acres in 4 in. cells (usually 18 cell Speedling type trays) and plant them to the field just as the first flowers are starting to open as early in April as they can to get by freeze and frost damage. they use overhead irrigation for frost protection. this gets them to market as early as they can in June, depending on how it warms up after they plant so they can get the premium price for the early home grown market. We have even had some growers who have produced transplants in 1-gal. pots and have the first fruit set on the plants when they go to the field. The trick with using a more advanced transplant to go to the field is to have enough root system to support normal growth of the transplant when it goes to the field. You could have plants with fruit on them from a 2-in. cell to go to the field, but the plant would not have enough root mass to support normal top growth, and you would end up with a very stunted plant with just a few small fruit early. If I were growing the final plant in a quart or larger container, I would grow initially in a 24-cell tray, transplant before flowering to a quart pot, and then from the quart pot to a larger pot if I were taking a larger plant to the final planting site. This would make management of plant growth easier during the transplant production and require less heated space earlier in the season.
This same principle would apply to growing tomatoes in unheated tunnels to get early season production. If I were growing in this system, I would put as large a plant as I could afford to grow in a heated greenhouse into the unheated structure. I would use raised beds in the unheated structure covered with black plastic to capture as much heat in the soil as I could in early season. Also,don't mulch between the beds. I think spring is the time to focus on getting early season production in tunnels. In the fall as temperatures cool down you have a large plant so the fruit stay cool under the canopy and ripen slowly. Also, in the fall there is generally less demand for fruit unless you have a specialized market. Your situation may be different but that's the way I see it.
Randy
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