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Hardening seedlings #903197

Asked May 27, 2025, 8:55 PM EDT

I have started cucumbers ifrom seed indoors. I wanted to get them acclimated to the outdoors so I put them outside before I left for work. When I came home, the leaves has white around the edges. Did I give them too much sun and heat? Will they be OK and is there anything that I should do for them?

Hillsborough County New Hampshire

Expert Response

Hello Kristen, 

Thanks for reaching out to the UNH Extension Yard and Garden Infoline. It looks like your plants got a little bit sunburned. However, don't fret too much, they might still be ok. Those leaves that have a tan outline might die back but as you continue to harden off your plants, the new leaves will probably grow in and be ok. I'd worry more if your plants became droopy and didn't stand back up or if the burn were more than at the edges. 

Hardening off transplants can be a long (1-2) week process and it can be difficult if you aren't at home to keep tabs on your young plants. I personally struggle with it every year! 

Here is a resource on hardening off seedlings-

https://extension.psu.edu/hardening-transplants


I hope this helps and please ask if you have any further questions!

Thank you for contacting the Yard and Garden Infoline, a service of UNH Cooperative Extension Replied June 02, 2025, 2:56 PM EDT

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