What's causing this odd discoloration in my brassica seedlings? - Ask Extension
Hello! I’d love some help diagnosing what’s wrong with my brassicas. I’m a 2nd year gardener on the windy Oregon coast in Florence, and felt ver...
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What's causing this odd discoloration in my brassica seedlings? #867136
Asked May 05, 2024, 6:42 PM EDT
Hello! I’d love some help diagnosing what’s wrong with my brassicas. I’m a 2nd year gardener on the windy Oregon coast in Florence, and felt very prepared and excited going into this growing season, but now I feel like I’m questioning everything.
I have an in-ground garden bed that has brassicas including the anemic looking arugula and kale pictured, and I don’t understand what is causing them to struggle so much. I started them from seed indoors 35 days ago and transplanted them into the garden about 16 days ago. When they were transplanted outdoors they looked great. I did this many times last year with great success though not this early in the season. In the past two weeks they have slowed down considerably and are starting to change to this weird dull brown. It’s been cold and wet here but not crazy cold, probably averaging lows of 40s and highs of 60s. I was under the impression that brassicas are pretty cold hardy so I didn't think they would struggle so much.
I did a soil test last fall and most of the nutrient levels were optimal, though phosphorous and potassium were incredibly high and nitrogen wasn't measured. I planted the brassicas with some worm castings and a bit of light organic nitrogen fertilizer and have been avoiding using any fertilizer with phosphorous and potassium because the levels were so high in the test. I’ve also applied worm tea once every other week and the plants show a tiny bit of growth but lots of discoloration now and seem super stunted. My instinct tells me they just suffered in the early cold/wet/windy conditions, but I’d love to know if there’s something else at play here, especially if it has to do with soil fertility or disease so that I don’t have this same issue throughout the season. In particular I'm curious about whether or not this discoloration is from a lack of phosphorous, and if there's anything I can do to make the very high levels of that nutrient already existent in the soil more readily available to the plants so that I don't need to add more in fertilizer.
Thanks in advance for your help!
Lane County Oregon
Expert Response
You are doing everything right and the weather is doing everything wrong. Purpling is a common sign of too cold, esp. for a young plant and of saturated soil. It is a stress response. Now that the weather is warming, and perhaps less wet, they should start to grow. Few plants can tolerate a low oxygen environment as in saturated soil.
Thanks so much for your reply! That is encouraging to hear. Hopefully things turn around with the lovely weather now!
You are welcome. Good luck!