This is my second year of growing Imperial Star Artichokes from seed and planting them as an annual. We had a terrific crop last year. Artichokes are a favourite but almost impossible to find here. When the store does have them they are incredibly expensive and very very tired looking. I start mine in January under T5 grow lights in a sunny window. Last year I experimented with homemade root trainer pots and had some issues with damp/moldy soil on the bottom. The leaves began to form necrotic papery circles. When I potted up I dipped in diluted peroxide and once I started to have them outside to verinalize the problem went away. This year I went with smaller pots, planning on more potting up because of their tap roots, and be darned if the leaves are forming the same papery necrotic circles. Just ugh. I know it has to be something I'm doing wrong.....my guess is too much watering although I try to let them dry out in between, and perhaps I could have over fertilized??? I use a half dilution and only fertilize every couple of weeks. I've raised the lights a bit more, although they are in the correct distance for growing. I have a fan for airflow and temperature is regulated. I'm at a bit of a loss. I've emailed the University of Oregon's Agriculture Program asking them as well. If anyone has any experience with these papery necrotic circles on an artichoke or other plant leaves, I'd be grateful for the input or any suggestions. The photos show the beginning of the circles. They spread and get larger.
Just from looking I would guess its from water droplets on the leaves and heat from the gro-lights ! Similar to a blister ! I assume it hasn`t affected the harvest ! Just looks bad but it isn`t dangerous to the plant !
This photo is a little decieving as usually the spots are randomly on the leaf. This little friendly missed my scissor purge yesterday.
I totally thought the same thing Mart...but the leaves are so darn big they don't get water on them. And when they are quite dry I bottom water. Having said that though....because Arties are more conducive to the mild west coast and I'm trying to trick them out....I wonder if the lights are just too much for them?? Sure presents like some kind of a fungal thing. I'm just stumped. But also...I chopped off all of the sick leaves last year, and you are right. It just kept chunking along. Can't be a coincidence that when I kicked them out last year it stopped?
OK,, Try an experiment ! Before the spots start spray the plants with a diluted milk spray ! About 50/50 ! See if that helps ! Its supposed to help powdery mildew,,maybe it will help on this ! I rarely worry about anything that doesn`t hurt the harvest !
@mart I've put a lot of thought into what you said about the lights. It's been my experience that a fresh set of eyes on a conundrum often leads to the most obvious and overlooked of possibilities. I really appreciate the sage advice about not worrying about what won't hurt the harvest. That is absolutely true and good advice I needed to hear. You're right - we had a great crop even with this weirdness. The plants never became sick, they just had weird leaf spots that eventually killed the leaf ( which I would eventually just chop off). And I also think your're onto something about the lights. It's the only thing that logically makes sense at this point. And they do presest as burns/blisters. I'm going to try elevating the lights to a maximum, just to supplement the window light rather than replace it. As well, I'm going to lower the room temperature a couple of degrees to their happy place. I might have to kick them to another room once the tomatoes show themselves. Only 4 - 6 weeks until they go out on the porch hopefully, maybe even sooner. And that's when it stopped last year....so what you said made a lot of a sense. Once they aren't in the house, if it is still happening I'll try the milk spray. Thanks so much !!
