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Nh

Been a while since I’ve tried to grow a respectable pumpkin. I was a little late getting planted, so this year I put up a 12 x 14 greenhouse instead of my usual small 4 x 8 hoop house. The bigger greenhouse really pushed the plant. Fastest I’ve ever had one get to around 14 ft, with a nice Christmas-tree shape and first secondaries around 8–10 ft.
I rolled the sides up once it started running out. Pollinated a pumpkin on July 8, plant was around 16 ft at the time. Soon after, the bigger secondaries behind the pumpkin slowed to a crawl. Tips got bunched up with small male flowers and lost that fresh running look. Secondaries past the pumpkin stayed fresher but were still only a few inches to 2 ft long.
After a couple weeks of no real movement, I terminated those stalled tips and buried them. Also cut the main tip around 18 ft. Plant is probably around 200 sq ft now. Fruit was DAP 15 yesterday, about 40" circumference.
Question: Is there a trick to keeping secondaries growing for a few weeks after setting a keeper, or once the keeper takes over is it pretty much “the plant you have is the plant you’ve got”?
Wondering if the stall was mainly from:
fruit becoming the dominant sink
exposure shock after rolling up the greenhouse sides
possible overwatering from first-year drip irrigation
Curious what others have seen.

7/25/2026 8:06:22 AM

Grittyville, WA

Great question. I think there is a nutrient and hormone answer, and it's a balancing act (because having the pumpkin be a strong sink is a good thing). The secondaries can continue to grow they probably need various forms of nitrogen and phosphorus mostly but also good levels of micronutrients. I would speculate that they need sufficient minerals/nutrients both to continue to grow and to synthesize auxins. Nitrate might be the biggest single factor but there are probably other important factors... Just my non professional opinion.

7/25/2026 11:45:08 AM

Grittyville, WA

It will be harder to restart them after they have stalled so it would be best to try to address the problem as soon as you notice it, probably with small doses of a foliar. Could be applied directly to the slow vines so as to not impact the pumpkin. A surge in water, and nitrate especially during hot weather might interfere with the pumpkin. The pumpkin could even abort. Just my half educated opinion... I may be reaching bit. Someone else can answer it better. Andy W or pumpconn or other top growers are pros. at this.

7/25/2026 11:57:27 AM

Ma

I would like to know if anyone has definitively discovered what makes pumpkin vines shoot additional growth? I had hope to grow tertiary vines off my minimal secondaries behind the set pumpkin but I haven't had a one form. I had continued the main vine growing a
but that eventually stopped on its own and shot out a bunch of leaf stems about 20ft past set pumpkin. I sprayed the nodes with 5-2, Sprinkled big foot azos, but zero tertiary growth. The 20ft main past the pumpkin shot secondaries every other leaf node but still no tertiaries starting. My other plant started throwing tertiary vines but only after the sides were 24 ft long and started with new pumpkins. Crazy fun trying to figure this out

[Last edit: 07/25/26 6:07:44 PM]

7/25/2026 6:05:23 PM

Grittyville, WA

Some growers curse at all the tertiaries popping out randomly. They might like to know how to make their pumpkin a stronger sink and have less tertiaries! Ideally the pumpkin would be a strong sink but the plant growth would remain steady? I think advancing eco agriculture mentioned this paradox in terms of tree fruit. Growers want the best of both worlds, nice strong shoots for the next years crop, but also big fruit this year. The brix levels might be the one hinge that lifts both sides of the teeter totter.

7/25/2026 6:35:14 PM

Ma

I guess if the plumbing isn't ideal before or event after setting fruit, you can't fill that sink so understanding how to get some additional vine growth or what may have slowed it down is great knowledge, I just don't got it :-)

7/25/2026 7:26:04 PM

Kalamazoo

I experienced a drip irrigation setback this year as well, easy to over water, so calcualte how much you are actually putting down as a starting point. You could be limiting what the plant can do if you have too much water, I saw a response in growth when I dialed that in, soil needs to breathe. I'd also send in a tissue test to see what's happening, just in case.
What's your fertility program look like? Anything that would be slow release for late season?

7/26/2026 8:27:41 AM

Bethlehem CT

I have noticed all plants react differently once a big pumpkin is packing on the weight. Some plants don't grow much, others keep putting on the vine growth. Some plants have the vines slow down at first then slowly get going again. Either way as long as your pumpkin is growing rapidly that is the most important thing. If your pumpkin had stalled, I would be more concerned that it was something else.

7/26/2026 8:51:20 AM

Upa Creek, MO

Agree 100% Big Moon. The only vine that is still growing at all on my one pumpkin plant is a secondary on the main AFTER the pumpkin. I figure I will let it keep going, but I have hit the plant with all types of ferts and nothing will grow before. Other years, I cannot stop growth.. I terminate and then it pops up terts.

I had a sterile plant that I pulled earlier this month and would like to fill in some of its designated spot, but no luck.

7/26/2026 11:05:30 AM

Nh

So the secondaries on my plant took off like gangbusters. I knew I was late in getting the plant in the ground so I pollinated a fruit around 14ft out on a decent but small plant. Its really only 150 to 175 square feet. Once fruit set it shut down almost everything. I do have one secondary after the fruit chugging along. At 16 days old today, the fruit has a 45 circ and a 112 ott. Not bad and is kinda surprising. Im using only jacks 20-10-20 soluble fert. Think its the peat-lite kind that has micro nutients.

7/26/2026 11:10:12 AM

Grittyville, WA

Thats interesting. Maybe the big plants that are throwing tertiaries have too much energy, even in addition to the pumpkin they are supporting. A smaller plant will be affected by the loss of energy especially in regard to pushing out tertiaries. Even the secondaries may lose momentum. The fact that you have one secondary still growing might be the ideal setup. Plant pruned itself and is fully invested in the fruit. Not a bad problem to have. Still a great question though, next time maybe try for a bigger plant prior to pollinating.

7/26/2026 2:25:54 PM