Weak and sappy lettuce

Yesterday I transplanted my lettuce from a pot I thought it was crowded but today the leaves look very weak and sappy :( I'm a novice in gardening and I don't know what could I have done wrong and how to amend it.
Thanks!!
I have attached a picture of them.

 

Good evening Nessi and welcome to the site. Did you water them before / after transplanting them? Give them a couple of days to pick up, either way.

 

That's it that's all it is I transplant mine and they take a whi
le to man up.

 

They look ok and should hopefully pick up in a few days, especially the newer growth in the middle.

I usually grow lettuce in two ways;

One I sow them thinly in the ground in rows and then thin them out as they grow to leave enough space between them to grow to mature lettuce.

Two I always like to grow some in cell trays; 2-3 seeds per cell, then thin down to 1 seedling per cell if they all germinate, I then use these plug plants to fill in gaps or plant along the outside of runner beans etc...

 

Thank you all for your answers!!
Well, I watered them after transplanting. I hope they grow ok

 

No, there are no holes in the container despite I bought it at Homebase and apparently is perfect for growing vegetables

 

drill some holes near the bottom to help drain. all around the pot/tub

 

That's a good tip; I always prefer to drill holes in pots around the sides instead of the bottom, that way a little water can collect in the bottom like a mini reservior...

 

You'll probably loose the outside leaves but the middle will pick up.

 

Yes, when I bought it I was thinking in drilling some holes and now, after all your advices, definitely I'll make them tomorrow
Thank you!!!

 

You could still tilt the container and poke a few holes with a bradall or something sharp and strong. There's often marks where the plastic is thinner ready for drainage holes.