Wilting Brassicas

[invasian03]

Hi all,
I have an annoying problem with growing brassicas, specifically Cabbage and Broccoli.

Problem: Anytime the plants are in direct sun, the plants start to wilt dramatically. It happens within 5-10 minutes of sun exposure.

1. This occurs even during the spring, when temperatures are 60C and really cool.
2. This occurs even though the soil is moist (I have a moisture meter)
3. This occurs even at the seedling stage
4. If the plants are in direct sun and wilt, I cover the plants with shade cloth and they'll bounce back

Some more background:

I know one of the problems I have with my soil is that it is contaminated with clubroot. To combat this, I start my seedlings in sterilized soil mixed with lime. Since wilting even occurs with seedlings, I can't imagine that it is clubroot related. I have also pulled up plants at harvest and in some cases, there is no evidence of clubroot at all.

When I plant into the ground, I amend the soil with lime and garden-tone. Growing under shade-cloth is ok, but I'd like to be able to not have to rely on it all the time.

Has anyone encountered a similar problem or have any suggestions for me to try?

 

[Meadowlark]

Those brassicas do not tolerate high sun angles well, in my experience. They are a cool weather plant that likes relatively low sun angles... again in my experience.

You might be able to help them some if you make sure you have adequate boron present in your soil.

 

[Chuck]

This sounds a lot like some nutritional issue to me. Garden Tone is good stuff but one cannot always go by directions as all soils are different. Do a test. Double the application rate on a plant and compare. On the seedlings you sterilize the soil, which is good, but just what is the growing medium? And how many true leaves do the wilted seedlings have? And are they fed with the Espoma Garden Tone?

 

[invasian03]

Chuck, I will try a double application in a couple weeks when I transplant the cabbages and report back.

For seedlings, I use a half mix of native soil and peat moss mixed with some perlite. I put moist mixture into an aluminum tray, cover it, and then grill on highest setting for 30 minutes. Temperatures reach well above 150C. Papers I've read indicate that this time and temp should kill the clubroot spores (and I imagine most other diseases).

For this fall's seedlings, I mixed with lime and added some garden-tone as well. Right now, cabbage seedlings have about 3 true leaves and if the sun hits it, the largest one will wilt. If left out long enough, I think the plant would shrivel up and die.

I have tried reading up on brassica nutrient deficiencies, but none seem plausible: https://projectblue.blob.core.windows.net/media/Default/Imported Publication Docs/n21y05.pdf

I am also trying this cabbage variety which has clubroot resistance: https://www.osborneseed.com/catalog/item-content/69497/kilagreg-f1/pr_69497 ; seedlings are just starting to sprout, so I'll see how it compares

 

[Chuck]

Chuck, I will try a double application in a couple weeks when I transplant the cabbages and report back.

For seedlings, I use a half mix of native soil and peat moss mixed with some perlite. I put moist mixture into an aluminum tray, cover it, and then grill on highest setting for 30 minutes. Temperatures reach well above 150C. Papers I've read indicate that this time and temp should kill the clubroot spores (and I imagine most other diseases).

For this fall's seedlings, I mixed with lime and added some garden-tone as well. Right now, cabbage seedlings have about 3 true leaves and if the sun hits it, the largest one will wilt. If left out long enough, I think the plant would shrivel up and die.

I have tried reading up on brassica nutrient deficiencies, but none seem plausible: https://projectblue.blob.core.windows.net/media/Default/Imported Publication Docs/n21y05.pdf

I am also trying this cabbage variety which has clubroot resistance: https://www.osborneseed.com/catalog/item-content/69497/kilagreg-f1/pr_69497 ; seedlings are just starting to sprout, so I'll see how it compares

I think you have answered your question. Your seedlings are started in garden soil. I don't think you are heating the soil to a high enough degree and are possibly not using enough lime on the seedlings. If you can stop the seedlings from getting clubbfoot totally and start out with non infected transplants, I believe you will have solved the problem. Here is what I would do. I would NOT use any garden soil starting the seedlings. I would start the seeds earlier in order to have a larger more robust healthy root system. Use only a sterilized potting mix. I would increase the amount of lime in the garden by 25% this year and if the problem persists add another 25% next year. Make sure that your soil Ph is about 7.3 or higher. Another thing you can do is solarize the entire garden next summer. I would still double the amount of fertilizer just in case.