[boddy]

Hi. Im going to plant my tomatoes in my greenhouse tomorrow. Usually I would plant then up to their first (seedling) leaves. However, I have truly neglected them and they have lost both their first and second sets of leave and are therefore very legging. Can I plant them up to the next set of leaves? Thanks in advance. ☺

[mumofstig]

I have planted up to the first set of proper leaves, many times, as some of the toms I grow get very tall otherwise.
You do sometimes get a 2nd stem growing from below soil level, though.
If it looks to be strong enough, I give it its own cane and treat it the same as the mother plant (taking off any extra armpit growths) it's a double cordon tomato, in effect.

2 plants for the price of one - can't be bad 

[AlaninCarlisle]

I learned many years ago that you get sturdier plants by planting very deep. The root system starts just below soil-level however deep you plant them

[Nobbie]

I had some leggy plants that had fallen over and bent at the end, so I just planted them horizontally with just the top 8" showing and they romped away. At the end of the season when I dug them up they had rooted all along the buried stem.

[Aunt Sally]

I have on occasions planted them much deeper than their first true leaves.  I remove the leaves that would be below ground first, of course. 

As Nobbie said, they will produce roots from the underground part of the stem.

[sunshineband]

I like the sound of the second stem coming up as well!