A tomato conundrum

Anyone kind enough to follow this blog may be forgiven for wondering whether, after all that, I actually grew anything in my fabulous new greenhouse.  Well, yes.  I've started.  I don't expect to use it to its full potential until retirement or at least semi-retirement but once we knew we were staying here for the summer, I set about sowing my usual quantities of tomatoes.

I usually grow three varieties:

Sungold is a cherry tomato that ripens to a glowing orange colour and is the sweetest tomato I have ever tasted.  As such, I suppose it might not be to everyone's taste, but we both love them and can happily eat them like sweets.  The plants grow like stink (how nice to be able to use that possibly antiquated but punchy little phrase) so I plant them at the front of the tomato area where the roof is of course higher.  In the old greenhouse they grew further and I used to have them trained along the cross-pieces but this greenhouse has a higher roof so I don't know if they'll grow quite so tall.

I then grow two other varieties, a standard tomato and a plum tomato.  These I choose from the wondrous variety offered by Franchi (Seeds of Italy)  whose seeds, I may have mentioned before, are always of excellent quality and arrive in plenteous quantities too.  I can't remember which two varieties I have this year.  It's not relevant to the conundrum.

So, I have 26 tomato plants arranged in two rows of thirteen.  Starting one variety from the back left and Sungold from the front left and then the third variety filling up the end section front and back.  There are eight of the back row plants and ten Sungold in front. 

The plants were all potted up in one session.  I started with a stack of pots and an open bag of compost.  When the bag ran out (halfway through potting up one variety) I opened another.  After they were all potted up in three little groups I arranged the plants as described above.  Patience, patience, there is a point to these tedious details.

For a few weeks I got on with watering with a watering can.  When I remembered to water I watered the whole lot, starting at one end and doing front/back, front/back until the watering can was empty and then refilling and continuing.  Usually two cans full did it, occasionally the last two plants had to start a third.


So you see, the way the plants have been raised and treated (identically), there seems to be no logical explanation why the eight on the left (some of variety A and some of variety B) are dark green and healthy looking and the eighteen on the right (some each of varieties A, B and C) pale and slightly sickly looking.  The only difference is that the eight on the left are standing between the legs of a new staging frame while those on the right are between the legs of the old staging frame.

I'm flummoxed. 

Explanations and, even more so, suggestions about a remedy if one is available and would be beneficial, gratefully received.