Possible Downside

Brandywine OTV - Early July

I have talked about the benefits of a greenhouse for giving tomato plants a jump-start in cool climates.  But I am beginning to suspect a downside as well: many of the plants that spent the past two months in the greenhouse are tall, and starting to bear fruit, but they are yellow and listless, especially now that I have brought them outside.

Leaves are sparse and yellowish-green, without the dark green, springy character of other plants that have been outside all along.  What's more, a number of the plants from the greenhouse have dropped their flowers - usually a sign of stress.  It is hard to research the issue online, but I suspect that moving the plants from the high humidity of the greenhouse and putting them outside may be a bit of a shock.  This idea is strengthened by the fact that a couple plants (Sungold and Green Giant) were kept outside all along and seem more robust.

Since all of my plants were on a similar fertilization regime (inside and out) I do not really think it is a lack of nitrogen. I have fed the plants 2 or 3 times since they went in the ground in early May. I also don't think it's over-watering since all plants have been watered on a similar schedule. So what now?  I have tried foliar feeding to try and give the foliage a boost, but worry a bit about over-feeding.

I am thinking that next year I may use the greenhouses only to get the plants through May, normally a cold, damp month - and then move them outside on the first of June.