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Tauranga, NZ

Here's this season's grow on the 1584 Martin. Would welcome a view in terms of what could be causing the deficiency and ways of treating it. I'm thinking either Sulphur or Mn.

http://www.bigpumpkins.com/Diary/DiaryViewOne.asp?eid=340056

- Deficiency in new growth only
- Lots of rain over the past 40 days
- Temps between 10 - 20 degrees C. Former is night-time

7/24/2023 8:06:21 AM

Western NY

what kind of mulch is that?

7/24/2023 8:15:10 AM

Tauranga, NZ

Hi Andy, that is a straw mulch i'm using.

7/24/2023 8:17:28 AM

Grittyville, WA

Add magnesium to the list of could-be's... or is that what you meant? Mn Manganese, Mg magnesium... and whats worse is they can have overlapping visual symptoms. Hows your soil ph? If you have low ph and lots of rain I think it will really lock out magnesium badly. So badly that applying magnesium sulfate wont even change the appearane of the plant, unless you apply it very heavily in the rootzone, but then you could slighty mess up your calcium? Given the choice between adequate calcium and adequate magnesium, I'd choose adequate calcium. I may be unwise, who knows. Watching your ph/ buffering against acidity could help with both.

7/24/2023 10:11:04 AM

Grittyville, WA

Plant lools really good... kinda just looks like bad weather.
Ok, the truth is I dont really have a clue, lol... Other than some soils are really stubborn and I think the stubborness is a ph thing.
The fouth thing to consider is your soil may be perfect and it might just be the weather. I hope someone will agree, or disagree, with this...?

7/24/2023 10:20:38 AM

Grittyville, WA

Side note: Let's practice staying on topic on this thread rather than getting personal and just see how it goes...

7/24/2023 10:24:23 AM

Tauranga, NZ

I was more leaning towards Mn more than Mg, although won't rule out Mg. I guess a tissue test would confirm either way. What I didn't add at the beginning is the neighboring plant (2350) doesn't have this issue, and is arguably in the prime spot of the patch i.e. lighter soil (more perlite etc). The 1584 spot is perhaps on the heavier side and more likely to hold water.

7/24/2023 10:33:37 AM

Grittyville, WA

Waterlogging could cause a lot of acidity... and low transpiration and high soil acidity would deplete magnesium. That idea gets a thumbs up from me. I dont know what the quickest solution is, I have a theory that the plant will deplete magnesium from its leaves in order to protect its roots. Even if foliar fed, the plant will continue to move any & all magnesium out of its leaves, down into the roots, which is a really weird theory, and I have nothing to back it up except that magnesium is a highly mobile nutrient within the plant. I my theories are like nails on a chalkboard to some of you...! I do apologize for this.

7/24/2023 11:49:21 AM

Grittyville, WA

The leaves wont improve until the plant is certain its roots are no longer threatened. Crazy, and perhaps 100% wrong, :)

7/24/2023 11:52:00 AM

Springfield, VT

A saturated soil can cause the discoloration in the leaves, until the soil dries not much you can do about that. Usually it only shows on new growth.

7/24/2023 3:01:27 PM

Bethlehem CT

Lots of good advice here. Cold wet soil is enough to induce some deficiency's by itself.

7/24/2023 7:55:56 PM

Upa Creek, Mo

20C is low 70sF, that is cold for a high... very cold. I'm with Wilbur and Big Moon, I'd let the soil dry out a bit if possible.

Why do you have the straw mulch on when it's already so wet? I'd want my soil to breathe. Just asking since I am in a completely different climate than you.

7/24/2023 10:12:18 PM

Tauranga, NZ

I think we have consensus, thanks all. My immediate thought was to tackle what I thought was a nutrient deficiency, not so much what might be causing it. All the clues were there, extended wet period, low temps, moisture retentive soil, and a thick mulch over the grow area.

Next steps... Hope for some better weather and begin removing the wheat straw I put down at the beginning of the season. Last year I used a liberal amount of milled straw in grow which worked well for weed control and retaining moisture, in what was a warmer year than this one. Milled straw is also quite friable, which let the soil breath and gave it structure. This season I used straw bales for convenience and cost reasons, although I didn’t anticipate the mat it would create over the dirt and the subsequent issues that fell out what I thought was a good decision at the time. You live and learn as they say.

7/25/2023 4:27:46 AM

Bethlehem CT

Your plant looks nice and you obviously know how to grow. Don't beat yourself up to much over it. I have grown on straw mulch before, buy my vines were grown on top of it.

7/25/2023 8:12:30 AM

Grittyville, WA

Ive tried thick matted hay also for weed suppression and soil improvement, but it needs warm temps to release nitrients and very little if any irrigation. Thin mulches, an inch or less, are my go-to standard now!
Other than removing or fluffing the hay (which could be useful, unless you're in for a hot/dry/or windy August) I'd try throwing down some magnesium sulfate. (But without watering it in, any extra water at all, will really not help).
I think broadcasting the magnesium sulfate salt on the hay would help dry it, in the same way people salt the hay in their barn to help dry it?
In its non-hydrated form its considered a drying agent (a desiccant). If do you get a sunny or dry day, it will convert to its non hydrated form, but then it can absorb moisture again at night. It might only suck a few pounds of water out of your patch, but it shouldnt be harmful. The little things we do, they do add up!
Just an idea.

7/25/2023 11:09:59 AM

Grittyville, WA

Ps I was just out on my own patch throwing handfuls of magnesium sulfate under the leaves. It can be done without getting it on the top surfaces of the leaves, just have to stoop down and cast it out from near ground level, more like the guy on the right:

https://ericcressey.com/pitching-mechanics-release-point#:~:text=In%202019%2C%20his%204-seam%20fastball%20had%20an%20average,throws%20a%20sinker%20at%20a%203%3A48%20spin%20axis.

7/25/2023 11:21:39 AM