Hmmm,

the yellowing looks almost identical to mine...considering the similarities between our setups I would think that this is not a coinsidence. However mine do seem to be perking up a little.

As you the purple...no idea at all!

Have you started feeding them yet? I have still not got any nuts just yet, but have been watering them every two days now and not every day. Seems to have done the trick.

This is my strongest plant, still yellow at the bottom...but nice and green at the top. Anoying thing is though, it is quite a bit taller than the others Going to start feeding tomorrow...will pop to local gerden center(s) and find some good food for them.

Hope your plants pick up soon, I'll let you know if feeding them has any effect...(hope I don't kill mine!)