I am kind of regretting being in such a hurry to get the tunnel house up and running, especially since summer has come round. I am now taking out the dirt I hastily put in, and adding some water gel crystals. Poor plants are wilting so fast. At least I thought of it now before summer really kicks in and I can top them up a bit more with some organic matter like worm castings and compost. It's going to be a very trying summer in the tunnel house working out all the kinks, but hey... that's gardening!