Somebody mentioned deep planting of the stem. Well here is one that you
may find hard to believe but its true. we grow tomatoes on rockwool. the
seed is planted in a small plug of rockwool which when they are about 10
days old is planted in a larger cube of rockwool. There is a hole
drilled in the top of the cube to accomodate the small plug. The plants
grown this way tend to be a bid unsteady and fall over easily because
the seed is sown in a small indentation of the rockwool. To get a nice
sturdy plant we now plant the plug upside down in the cube. you need to
have a fairly leggy seedling otherwise its stem is not long enough but
it works. The plants don't seen to mind having their stems bent 180
degrees and the result is good. Losses are very few and it is standard
commercial practice now.
Tim Riley
Riley growers
Gloucester, UK