Pumpkins with yellow leaves -- what do I need to do?

This is my first year growing pumpkins.  I started them in peat pots and planted them in my new hugelkultur. When I planted them I dug down to the dirt, and made a well then I filled it with a mixture of organic compost (I don't have any of my own yet, so it is the kind you buy)  Organic chicken manure, and an organic veggie fertilizer, I think Dr. earth and Down To Earth Organic Bio-Live Fertilizer Mix 5-4-2, 5 lb.   They are growing amazingly well.  I have been so impressed with the results.  Now the pumpkin on the Hugelkultur mound that is built with the walnut that fell this year's leaves that are closest to where the plant comes out of the ground are turning yellow.  So I used what I planted them in with the addition of bone meal, and sprinkeled a little around each plant and worked it into the soil a bit.  I didn't put a lot, maybe 1/3 cup around each plant.  I didn't want to burn them.  I did this about 1 week ago.  The yellow leaves continue to go down the plant.  Everything elce is still very green and the pumpkins are growing like mad.  I don't know if I need to be more patient, or try a liquid fish fertilizer, or a compost tea.  
The pumpkins planted on the hugel that was built with old wood that was not walnut are still very green and showing no signs of nitrogen deficiency.  My guess is this has more to do with old wood versus new wood rather then walnut versus other.
What should I do to keep this pumpkin healthy?

We always got the biggest pumpkins by fertilizing them with milk. I think it had to do with the calcium, but I am not sure. We would pluck flowers to limit the pumpkins produced per plant, then water the plant with excess milk we had.

Yellow leaves or vines are typically a sign of lack of nitrogen, and with a mix of 5/4/2 you would get that. Of the NPK, that fertilizer is highest in nitrogen, but it is only 5, and for a starter fertilizer is kind of sucky. Usually a starter fertilizer is low on N, medium on P, and extremely high in K. My starter fertilizer is 5/16/41 if that tells you anything, then I fertilize later in the summer with a high nitrogen fertilizer. This is called "side dressing", to give the plants a fertilizer boost just before producing its crop. For me, that would be a fertilizer with a 42/0/0.

By giving the plants low nitrogen at first, it impedes weed growth, but the high potash (the K) gets the roots firmly established. Later when the weeds are crowded out by the vigorously growing plant, you "side dress: with nitrogen to give the plant the boost it needs just before producing.

You can easily tell if you lack nitrogen by looking for an inverted yellowish Vee on the leaves or vine. If it is there, you need nitrogen. If it is purplish color, you lack phosphrous (the p)

If it was a black walnut it is very possible you are encountering the Allelopathic nature of walnuts.  They have a chemical which inhibits growth in the soil around it. It is the way the tree fights competition.  The roots of your pumpkin are probably finally reaching down to the walnut wood and having a reaction.  All is not lost. The effects of this will lessen with time, so the Hugel is not a complete loss.

John Tietjen wrote:If it was a black walnut it is very possible you are encountering the Allelopathic nature of walnuts.  They have a chemical which inhibits growth in the soil around it. It is the way the tree fights competition.  The roots of your pumpkin are probably finally reaching down to the walnut wood and having a reaction.  All is not lost. The effects of this will lessen with time, so the Hugel is not a complete loss.

I forgot all about that John as we do not have Black Walnut here. I think you are very much onto the problem!

It is English walnut, and most of the new wood is at the bottom of the hugel. Some of the smaller wood in the middle and the top may be walnut, but  is a mix because I took it from the burn pile.  
This is the reason I have two hugel's instead of one. One with walnut, I without.  A kind of experiment.  Not a fair one though, because one has not only English walnut, but it fell this spring,. The other I tried to keep the walnut out, and It's wood that has been sitting around for two to three years.  In the beginning I could see no difference both hugel's where doing very well, honestly better than I thought considering the hugel's are new.  I planted the pumpkins about the end of July, this is the first indicator that something is out of balance.  Even being new I only have to water once a week, which is less than normal for this area and time of year. Thanks for your information.

Love Pumpkins!! Theyre my favorite to grow, next to squash.
This year i have an epic volunteer pumpkin patch in my compost pile. I love things that grow naturally in compost pile because its just one big amazing natural selection at its best fest!
I'm going to harvest the seeds from some near perfect pumpkins this year, and next year im going to start them early and plant seeds in both my garden and the compost pile, just to see how each does, and take notes about the growth rate, and pumpkins that come from my "experiment" :)

John Tietjen wrote:If it was a black walnut it is very possible you are encountering the Allelopathic nature of walnuts.  They have a chemical which inhibits growth in the soil around it. It is the way the tree fights competition.  The roots of your pumpkin are probably finally reaching down to the walnut wood and having a reaction.  All is not lost. The effects of this will lessen with time, so the Hugel is not a complete loss.

My squash are happily growing on Heartnut (Japanese Walnut). Sounds like nitrogen deficiency, Travis you always have awesome tidbits.

I try TJ.

I think with these things people think I am talking about commercial fertilizers, and while it is easy to just order exactly what a person needs using that, it can easily be done with animal manures. Like sheep have incredibly high nitrogen, so sheep manure would be used to side dress, and for starter fertilizer, steeped wood ash would be used.

It is pretty simple to give your plants what they need and when in natural fertilizing ways.

We always had good luck growing big pumpkins, it was growing big watermelons that we could never do. We would get them basket ball size, but not as big as the ones in the store. BUT...this is Maine.

Oh...here is another secret few people know about.

Those cans of Pumpkin Pie Filling...they are actually made of mostly squash.

(Insert Travis patiently waiting while readers go to their pantry and check the cans of Pumpkin Pie Filling and read squash on the content label)

Crazy huh? Back when we had canning factories here, they only bought squash for this reason.

A homesteader can do the same thing. Squash and pumpkins are pretty much interchangable for flavor.

(those of us who live in pumpkin-free lands may make a mean pumpkin pie with the local alternatives and not tell their unsuspecting Thanksgiving guests. Kabocha squash is my favorite, probably more flavorful anyway.)

Tereza Okava wrote:(those of us who live in pumpkin-free lands may make a mean pumpkin pie with the local alternatives and not tell their unsuspecting Thanksgiving guests. Kabocha squash is my favorite, probably more flavorful anyway.)

theyres always sweet potato pie, too!! YUM

I was wondering about chicken manure. I assume it would be too strong to use flash, what about putting a small amount in a bucket full of water, let it sit for a week or so? I did not try it because I was afraid I would burn my plants.

Squash are nitrogen pigs. As long as they are not stressed they can pull it in. In my experience you will get a surge of bugs, so i have been aiming for lower yields with more modest big pressure.

This is no longer an issue, because I must not have latched the door well last night, because I know I shut it.  Any way the chickens were free all day, and now my hugelkultur is down to the top wood,(not the first time this has happened) the vines are still there, but no leaves, and all the good sized pumpkins have holes in them.  They had a very busy day.  I am definitely fencing an area for them.  No more free for all!  The bright side is I no longer have to worry about the health of my pumpkins, and butternut squash.  Time to put the dirt back on the hugel and plant something else