Can anyone tell me what is likely wrong with my cucumber plants? I have had them less than a week planted in a container. There are drainage holes and I used organic potting mix and added plant fertilizer. Same mix I'm using for a tomato plant that's doing well. Temps have ranged from mid 30s/40s at night to 60-80 during day. I cover them at night and they are getting at least 6 hours of sun most days. I was watering them almost daily because the top of the soil was drying out. One started feeling limp so I removed it and let the roots dry off in case it was over watered and replanted. It stiffened back up some but now I'm noticing more and more of the leaves are getting spots or crispy on the two plants. I just removed a couple of the leaves but can't remove them all. Any suggestions are greatly appreciated!

The mix is too hot from the extra fertilizer, plus new organic potting mixes can have up to 3900 ppm of Total Dissolved Salts per gallon of soil. When you have that much salts and you water you release the nutrients with every watering. If the roots are very tiny thats why, because there is no need to search for nutrients. You would be better off using a smaller container in the beginning so you can release less nutrients with each watering. Germinate your seeds in small pots first and then up pott 2 inches at a time for best results.