You might want to be specific about what your problem is. I see some holes, so something is eating it. BT is a good idea, but you should keep your eyes peeled for snails and slugs, especially at night. Flea beetles are another possibility.

Here (out in the open) some late season cuke beetles look around for just about anything to eat and they do similar damage to my greens including spinach. Could be slugs too as Dan says. Did you inspect the underside of those curled leaves for any hidden pests?

Thanks for the thoughts. I have never seen a pest on our around the plants, and have checked under the leaves and found nothing The plants are misshapen, eaten and just do not grow. They are stunted, and stay stunted. But the leaves are dark green, with no spots or unusual yellowing. And, as I said - 2 sprays of BT has made no difference. Funny, because this happened last winter too, and I never did figure it out. Well thanks for your help. I will keep trying. I think that I will plant some spinach in another part of the greenhouse and see if the same thing happens.

Hate to say it, but stunted plants and deformed leaves are often the result of a viral infection. As in Cucumber Mosaic. It's pretty common. Was this a Mosaic resistant variety of spinach? Resistant varieties are available.

It is a long shot but spinach is pretty sensitive to low pH. If you added a lot of peat moss, which is very low in pH, it could be low pH. By adding Ag Lime you can raise the pH level. Over time your water should raise the pH, esp. being in New Mexico.

I will try some mosaic resistant varieties. Sounds like a good idea to try. I did have problems with a low Ph in my greenhouse last years - due to an overzealous application of sulfur. I have corrected it with lime, but did sprinkle a little lime around the plants just in case that is it. And thanks. Peggy

That's a good point that spinach doesn't take kindly to acid soil, but I think it's a nutrient availability issue, and will mainly retard growth. Not clear that low pH soil is going to make anything grow with deformed leaves, though.