If your tomatoes are 6-10 inches tall and have blooms forming, they should be repotted into 1-gallon containers. The early 80-degree heat may have encouraged your tomatoes to grow a bit faster. When you repot them, remove the lower leaves and plant them to just below the lowest remaining leaves. This will allow additional roots to form from the buried stem, making the tomato plants stronger and hardier. Be sure to water them well.

Tomatoes should not be planted until after the last frost. Your tomatoes can safely be planted during the latter part of May and the soil temperature should be around 60 degrees. Before planting outdoors, be sure to “harden off” or gradually expose your tomatoes to the outdoors by moving your plants out of the greenhouse during the day and put them to a wind protected area with dappled shade. Take about a week for the hardening off process and be sure to bring the tomato plants back into the greenhouse at night.

If you have no other choice and cannot wait until the ideal conditions to plant your tomatoes outdoors, be sure to protect them from the cool night temperatures with a fabric row cover or walls of water (water-filled milk jugs).

The link OSU Master Gardener 10-Minute University - Growing Tomatoes in the Home Garden also has helpful information about planting tomatoes.