Question
zone 6b when is a good time to plant lettuce and cabbage i can start them indoors and then plant outside.

Answer
Mikki, the last expected frost for zone 6b is usually around April 25th. For cool-hardy plants such as lettuce, cabbage, broccoli, radishes, and spinach, you can transplant one week earlier. For tender plants such as tomatoes and peppers, you should transplant two weeks following your last frost date. Most other plants can be planted the weekend following April 25th.

I am attaching two links that will give you a good idea as to when most vegetables can be transplanted. This will give you a good reference going forward.

http://www.thegardenhelper.com/hardiness.htm

http://www.victoryseeds.com/information/plantingdates.html

In regards to starting seeds indoors, most vegetables should be started four weeks prior to your transplant date. This gives them enough time to establish a root system and to withstand the transplanting process. Just keep in mind that all plants should be hardened-off prior to transplanting outdoors.

Hardening-off is a method of slowly acclimating indoor plants to outdoor conditions.  This is necessary because they have been in a controlled environment over the winter and need to be introduced slowly to the changes in temperature, wind, sun, and rain.

This is accomplished by placing them in a shaded or covered area for a few hours the first day to protect them from the wind and sunlight.  Keeping them under a covered porch or in a cold frame are both good options.  Leave them out 6 hours the second day, 12 hours the third, and the entire day the fourth.  Each day move them more towards the sunlight.  The reason for this is to protect them from sun scald.  You can then plant them into the garden 7 days after starting this process.

I hope this answered your question. Please write again if I can ever provide assistance.

Regards,

Mike