Hi Mark-
I've grown Early Girl in EarthBoxes before. It didn't crack much -- at least at the start of the season. I like EG's flavor. The only drawback was that it was quite bushy, but that might be solved with only one plant per box. I'm definitely cutting back on the number of varieties that I grow next year (or so I say now
). Early Girl
plants probably outsell all others here in central Indiana. The size is just fine for us -- big enough for a (small) slicer, and excellent for salads. It's very versatile. I tried a "me-too" New Girl (in dirt) and really couldn't tell much difference from Early Girl -- maybe a bit bigger on average.
Hope your Matsu F9's turn out well!
-GG