Question
Can you give me any advice on starting tomatoes from seed in my greenhouse.  Size of pot, soil, etc?

Answer
Deb, tomatoes are one of the few vegetables that prosper from transplanting.  Therefore, I would start with the six-pack plastic containers, and then transplant the seedlings into a four or six inch container 4 weeks after germination. Also, tomatoes prefer to be planted slightly deeper each time.  This forces additional nodules to form at the bottom of the stem which improves the plant's ability to draw in oxygen and nutrients.

When starting seeds, always use a soiless mix.  This is usually a combination of vertimiculite, perlite, and peat moss.  You can purchase seed starting medium at any reputable nursery or garden center.

Finally, do not fertilize the seedlings until they are at least 4 weeks old.  Use a starter fertilizer formulated specifically for seedlings.  You can also opt for an organic fertilizer such as fish emulsion or kelp.  Water only when the surface of the soil feels dry.  Never overwater or you can do damage to the young root system.  In other words, keep the soil slightly moist at all times.

I hope this answered your question.  Good luck, and please write again if I can ever be of assistance.

Regards,

Mike