From

Location

Message

Date Posted

Richmond, BC, Canada

Matt, what a great discssion of what is happening at those leaf margins. I certainly get that in my patch.

8/7/2024 8:34:57 AM

Mill Bay, British Columbia

Yeah thanks Matt, excellent pictures and descriptions. I also see this every year and always wondered about the collection of water droplets and the burnt edges, thanks.

8/7/2024 9:10:18 AM

Australia eastcoastcitrus@hotmail.com

Great stuff the information you put up Matt is much appreciated

8/7/2024 3:18:12 PM

Grittyville, WA

While it may be water or salt related, I dont think this is potassium. A couple ideas, first if the margin has water droplets at night this will hinder transpiration and it may cause chlorosis. I'd try some light foliar feeding of magnesium if that was the case. Second... I think alot of you guys are leaving out molybdenum and in many cases a narrow burn on the margin is actually a molybdenum deficiency. I added molybdenum last year and was pleased to have solid green out to the edge. I think it helped. If someone can point me to the original source that said molybdenum is not needed for pumokins that would be great. Meanwhile I would challenge that accepted wisdom and strongly suggest experimenting with it, there shouldnt be any downside as the plants should tolerate it well even if they dont need it. It should be dosed at a rate even less than boron, but from what Ive read it wont harm the plants even if a grower goes a little over that.

8/7/2024 3:51:35 PM

Grittyville, WA

Growers who use alfalfa products or certain blue fertilizers (some have it, some dont) will not see a molybdenum deficiency, but I think its pretty common for the growers who dont add any? Disclaimer: I'm going directly against the conventional wisdom here and I could be wrong. I hope I'm not way out of line in posting these opinions.

[Last edit: 08/07/24 4:00:28 PM]

8/7/2024 3:57:04 PM

Connecticut

Richmond Dave- This is a sign you are likely fertilizing near the max the plant may be able to take.

North Shore Boyz- If you wash the leaves in the early morning you may be able to prevent the burn. Glad you like the images and description, this only took a couple years to figure out;-)

dale- You are welcome, trying to share the information I have accumulated over the years.

Little Ketchup- Tissue test conformed high (excessive levels) of potassium, and molybdenum is in my Plant Marvel fertilizer. (See posting on June 17th, 2024 or link to label... http://www.plantmarvel.com/wp-content/uploads/2017/07/Tech-Sheet-15-5-30-K-Mag.pdf

8/7/2024 9:52:58 PM

Connecticut

Easy to read format...

Richmond Dave- This is a sign you are likely fertilizing near the max the plant may be able to take.

8/7/2024 9:54:09 PM

Connecticut

North Shore Boyz- If you wash the leaves in the early morning you may be able to prevent the burn. Glad you like the images and description, this only took a couple years to figure out;-)

8/7/2024 9:54:21 PM

Connecticut

dale- You are welcome, trying to share the information I have accumulated over the years.

8/7/2024 9:54:39 PM

Connecticut

Little Ketchup- Tissue test conformed high (excessive levels) of potassium, and molybdenum is in my Plant Marvel fertilizer. (See posting on June 17th, 2024 or link to label... http://www.plantmarvel.com/wp-content/uploads/2017/07/Tech-Sheet-15-5-30-K-Mag.pdf

8/7/2024 9:55:00 PM

Grittyville, WA

Thats interesting.

Your diary is so full of knowledge Matt!

There may indeed be a link between high potassium and leaf margin symptoms but I can show a young leaf that tested high without any margin burn:

A leaf used in the test:

http://bigpumpkins.com/Diary/DiaryViewOne.asp?eid=338079

The test results showing high potassium:

http://bigpumpkins.com/Diary/DiaryViewOne.asp?eid=338081

I like the level of knowledge here Matt, trying to add to it if I can.

[Last edit: 08/08/24 11:54:25 AM]

8/8/2024 11:53:43 AM

Connecticut

Little Ketchup- The marginal leaf burn is more common in environments where the leaves are not exposed to water to "wash" the salts away from the margin. So, the toxicity margin burn is more common in covered environments, areas with minimal rainfall and when growers do not add water to the leaves.

Thanks for sharing your experiences as this is how we all learn through growers sharing what they have seen. By adding your experience it can help everyone and if anyone else has something to add, the option now to diary comments that Ken has provided is a great addition.

8/8/2024 9:36:44 PM

Grittyville, WA

Wow maybe Im needing to learn more... Do salts exude from the leaf itself, or is this regarding foliar sprays? ...Or both? Too much that I dont know! Thanks for the replies.

8/8/2024 11:12:03 PM

Connecticut

Little Ketchup- It is important to rember that when most growers hear "salts" they think of NaCl, but nutrients are also in a salt form so in this case the high level of nutrients (salts) in the plant have increased the concentration in the water that is forced out of the leaves and then there is the resulting margin burn.

8/9/2024 6:59:45 PM