Hello, my seedlings haven’t been doing well. They are getting plenty of light but I may have overwatered them at first. I have been watering them less but the bottom leaves continue to get yellow/purple/red and fall off. Many of them are getting white spots on the outside of the leaves that start to work there way in (it almost looks like a burn). Some have stopped growing even though they’ve been replanted in bigger pots. I’ve also been seeing white patches on my kale. I’m wondering if this is normal or indicative of a fungus/blight. I sprayed them with diluted neem oil at some point thinking it was a fungus but the seedlings continues to do poorly. Pictures attached of the various problems.
Ingham County Michigan
Thank you for contacting us with questions about your vegetables. You may have several unrelated issues, so I'll try to address each.
Red and purple tones in the lower leaves can generally be attributed to a couple of things. At this time of year, the most common is exposure to cold temperatures, especially at night. If your plants are outside, give them nighttime protection whenever the temperature may dip below 55 F.
If your plants are indoors and consistently in warmer temperatures, the issue may be that the soil lacks certain nutrients (but this would not be the case if you are using a potting soil that has nutrients already mixed in.) It is not possible to determine specific deficiencies without a soil test. Normally, I like to give seedlings a very weak nitrogen solution when they get their first set of true leaves. You can use fish emulsion at half-strength once a week, or use a balanced fertilizer (like MiracleGro or other) diluted to half-strength or less every two weeks.
A word of caution: if your plants begin to get too tall or put on too much new foliage, cut back on the fertilizer. You want them to grow roots, not foliage at this stage.
The lesions on the leaves are more difficult to assess without a physical inspection. If there are only a few leaves involved, I suggest you remove and destroy them (do not compost.) If it is more prevalent, it would be worth your while to contact your county Extension agent's office. I don't want to suggest a control without first getting a proper diagnosis. You can contact them here:
5303 S Cedar St, Lansing, MI 48911, United States