My question is in regard to my cucumber and tomato seedlings. This is my first year starting seeds, so not sure if this is cause for concern. The small lower leaves on the tomatoes are yellowing slightly and the leaf edges on the cucumbers seem to be dry. They're both about 5.5 weeks old and have spent a little time outside in the sun in the last few days (zone 8a). Certainly not a lack of water. Thanks!
It's normal for the first set of leaves (called seed leaves, or the cotyledon) to turn yellow and eventually fall off as the second and later sets of leaves (true leaves) develop. While the dry edge on the leaf doesn't look like sunburn (which causes leaves to turn white), it's worth knowing that seedlings grown indoors usually need to be accustomed gradually to outdoor light levels; this is called "hardening off". It can be accomplished by setting trays of seedlings in the shade (which, even though it's shade, is much brighter than indoor light) for a few days, before transferring them to full sun. However, the dry edge on the leaf may just be mechanical damage from being pinched by something... who knows? Probably nothing to worry about.
That's probably it. Those cucs went from a windowsill to direct sun outside. Good to know...thanks so much!
