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Eastern Pennsylvania

I've been stuck at 14.5ft for years. A lot of years. I have full sun. Why do my sunflowers bloom before getting mega tall? I try to only add mainly nitrogen fertilizer but that never has worked out.

Can some growers share methods for keeping plants in the vegetative stage for a long time?

2/6/2018 2:04:05 PM

Emmetsburg, Iowa

Have you tried different types of seeds? This was my first year of growing giant sunflowers and I had one grow over 17' without me watering or fertilizing it. Im not sure how i got so lucky lol

2/7/2018 12:11:25 AM

Syracuse, NY

TRY cutting off the leaves except for the very last few
near the developing flower head---i do believe there is a thing called 'apical dominance' you should Google big time on that subject---also, a high- or even average-level fertilizer containing SOME phosphorous will probably assist the plant in FLOWERING, so you may wanna look into 'delaying flowering in sunflowers' or similar; if it can't go OUT, it's gotta go UP, and the reverse----my nickel's-worth for the day - eg

2/7/2018 7:39:09 AM

Bethlehem CT

There was a study done on sunflowers response to daylight, some varieties grow taller under shorter days (12 hour) Others grew taller under longer days (16 hours)
https://hort.cals.cornell.edu/sites/hort.cals.cornell.edu/files/shared/documents/Daylength-response-of-sunflowers.pdf

As far as practical advice from this, and from what I have seen would be to;
Stagger your planting dates and see which ones grow the tallest. Sunflowers can tolerate frost so very early and late planting are possible options.
My tallest ever (16'7") were direct seeded around the first of June in 2016 and grown on a silty soil that held plenty of moisture. I have grow sunflowers for many years and have usually topped out around 14'. I was very happy with the 16'7" as that even tops my best corn height. I couldn't replicate my experiment last year because the deer ate off all my sunflowers and they became multi stemmed at the base.

2/7/2018 9:03:28 AM

Team Canuckle Heads

do you stake and tie your SF

2/7/2018 9:24:25 AM

Central NY

How bout the bucket trick?....

2/7/2018 9:39:22 AM

Team Canuckle Heads

I have grown with and without a bucket and get 20 feet + either way but if you dont stake and tie every 12 inches the stalk will get thick to support the plant and you will do well to hit 15 feet

2/7/2018 11:06:26 AM

Johnston, Iowa

My experience, the Single Head, black seed variety has always grown my tallest in the 15 - 19 foot range. I think adding a support structure would take it to the next level, which I've never done.

2/7/2018 11:42:11 AM

Bethlehem CT

Thanks John

2/7/2018 2:34:06 PM

Central NY

Wow awesome info...thank you...tie tight to stake?(..and don’t worry about size materz...I’ll be on his case this year...)

2/7/2018 8:25:20 PM

Wixom MI.

My best without staking was 16'-2" but marv mitchel and many others that grow 20'+ have a scafolding system so that they can easely climb as they tie their plants to a stake or pole !!!

2/7/2018 9:31:32 PM

Team Canuckle Heads

I tie just tight enough to support them and then loosen up as the stalk grows I also support the head as it grows to keep it 90 degrees cover the head with remay when the seeds are almost mature to keep the birds off

2/7/2018 9:38:45 PM

valparaiso, in

What is the bucket trick?

2/8/2018 12:28:23 AM

Owensboro, Ky.

Gritch, I will try to explain the bucket trick, as I understand it. Was explained to me w/ tall corn. 1st, cut top & bottom off of a bucket or barrel...place it over the top of desired plant, as plant grows taller raise up the bucket/barrel so that the top of the plant sees sunlight, as the plant grows taller, raise up the barrel. See how this works? Thinking I read this plan lots of years ago, w/new record corn plant! Obviously a lot of work to have a barrel on a pulley up high enough to grow a 25 foot tall plant. Lot's of work to just set it up! Peace, Wayne

2/8/2018 1:35:50 AM

Wixom MI.

What peace wayne said but by shading the tip of the plant with the bucket as it grows it is suppose to make the top reach or streach out longer ???

2/8/2018 10:45:43 AM

Wixom MI.

For some reason when you stake your sunflower to a pole every foot or so, it seems to make it stretch out ??? The main stalk is only 1/2 or 1/3 as thick as a free standing plant and the leaves space further apart !!! To me the plant is so thin that it almost look like a vine ! Im not Sure it could suport itself if you cut it from its suport ? The leaves and flower are also much smaller !!! Only my opinion !!! John buttler has much more experience in this subject than i have. Im going only by what i have seen !

2/8/2018 10:59:16 AM

Wixom MI.

In my opinion i don't know if these 20'+ tall plants have any more leaf count than a free standing 14'-16' plant, its seems like by staking them this way you just streatch them out to be taller !!! So this is a good technique for growing a tall plant !!!

2/8/2018 11:06:13 AM

Team Canuckle Heads

When using a 5 gal bucket I try to keep the top of the plant inside the bucket as Chris said. I have had stalks 20 ft plus long that only get to 1" diameter that will not support itself and 2 ft from that stalk another the same hieght with a 2" to 3" stalk that I have untied as it supported itself. same garden same ferts same year. Must be the genetics. They definitely strech out and get taller by tying. If you want to compete with Marvin your going to need to tie, use buckets, lean towards a nitrogen rich fert program, and hope you get better weather.

2/8/2018 11:21:07 AM

President - GPC

What is the WR on tall sunflower?

2/8/2018 11:44:50 AM

Team Canuckle Heads

according to Guiness 30 ft 1 in grown by Hans-Peter Schiffer (Germany)

2/8/2018 12:36:17 PM

Lewistown,IL

Wow there is alot of great info here.Super nice of you guys sharing techniques on how to get a taller sunflower. I did not know any of this.

2/8/2018 12:39:15 PM

Wixom MI.

I knew it but i dont like climbing that high !!! Great job john !!!

2/8/2018 12:41:56 PM

President - GPC

Seems like a lot of folks grow these as well, I know mine never go that high but our winds take care of that, even blows down the corn.... Hmmm

2/8/2018 12:44:06 PM

President - GPC

And also... isnt there a WR for head size too?

2/8/2018 12:45:40 PM

Wixom MI.

Make a strong enough scafolding you wont have to worry about it anymore !!!

2/8/2018 1:05:34 PM

Team Canuckle Heads

WR sunflower head 32.25" Emily Martin 1983 Canada

2/8/2018 1:32:33 PM

Team Canuckle Heads

I have posted an old pic of our growing stand on my diary if anyone is interested , The structure is 19 ft tall

2/8/2018 1:39:20 PM

President - GPC

Hmmm Sunflower.... not a GPC category....Hmmmm

2/8/2018 1:41:39 PM

Team Canuckle Heads

seams to be more interest in sunflowers then I thought.
They are always the hit of the garden by visitors

2/8/2018 1:52:56 PM

Wixom MI.

Hey john what size posts do you use for your scafolding structure ? 4x4 or 6x6 and how deep would you sink them ?

2/8/2018 3:13:16 PM

Salem, Ohio USA

If you are looking for large headed (diameter) sunflowers, we have Rose and Zappa state record seeds (28-29") in our seed sale. www.ovgpg.com Thanks. Ohio Valley Giant Pumpkin Growers

2/8/2018 3:29:54 PM

Team Canuckle Heads

we used 22 ft 6x6 buried 3 ft

2/8/2018 3:36:43 PM

Wixom MI.

Thanks i used 12 foot 2x4 for a long gourd trellis and it was to unstable to lean a ladder against !!!

2/8/2018 3:39:50 PM

Anchorage Alaska

thanks John , I have never heard of that technique before, might have to try it out with my butler sunflower seeds this season..

2/8/2018 11:36:04 PM

valparaiso, in

Peace, Wayne thanks for the explanation. I would like to see that system in action. My plants only got to about 14', but I was aiming for big heads on them. Not sure I would want a plant 20'+ in the air.

2/9/2018 1:21:52 AM

Syracuse, NY

Except for the possibility of strangulation, i see no reason to not grow a sunflower right next to a building or a tree at least 20 feet tall and by either installing a pulley as high as possible or managing a thin rope over the highest point possible and down again with a counterweight of a few pounds allow the rope, through a very soft and gentle collar of sorts around the developing head of the sunflower plant, to pull upward on the sunflower plant. Along with whatever other techniques and genetics are involved, this may help.
A WR awaits you.

2/9/2018 7:35:12 AM

Bethlehem CT

Great information, John that is a really cool tower you built. Thanks for sharing!

2/9/2018 9:06:26 AM

Team Canuckle Heads

I got all of my info from Fred Hain a true pioneer and all around great guy to have a beer with Hi Fred

2/9/2018 9:46:02 AM

Team Canuckle Heads

Good luck with the sun flowers Dale I hope the moose leave them alone

2/9/2018 9:47:48 AM

Wixom MI.

My suggestion is to be sure to make a sturdy structure and don't get skimpy !!! These things are tall and you don't wont to be up 15'feet in the air on a wobbly structure that can topple over !!!

2/9/2018 10:14:01 AM

Lewistown,IL

Here is a question. Does one start the seeds in a GH or just plant directly in the ground ? If started early --- How early ?

2/9/2018 10:40:11 AM

Team Canuckle Heads

I direct plant 4 to 5 seeds per hole (if available) 2 ft apart, put the open end 5 gal pail over the seeds ( keeps the bunnies from eating them when they break ground ) first one to the top of the bucket is the keeper the rest get cut off, Thet will be spindlely lite tie to support after raising or removing the bucket

2/9/2018 11:28:30 AM

Team Canuckle Heads

I use 10 ft pcs. of old top rail of chain link fence duct tape together for stakes. It makes it easier to take down
the SF

2/9/2018 11:32:35 AM

Wixom MI.

You could start in a pot only to germinate. Johns idea is better. I found that the pot will stunt the plant if you let true leaves grow in pot. For some reason they will bud up earlyer started in pots.huh

2/9/2018 1:05:52 PM

Team Canuckle Heads

I have in the past started in pots and found exactly that Chris they do bud early. There is really no need to start in pots as there is plenty of time to grow to maturiy

2/9/2018 2:56:16 PM

Lewistown,IL

Excellent, Direct sowing it will be.

2/9/2018 11:40:16 PM

Partlow,Va

Thanks for all these great ideas and information! I have been growing sunflowers for years and always get 10-14ft tall with tree trunk size stems.

2/10/2018 1:11:46 PM

Eastern Pennsylvania

Just what I was hoping for guys. Thanks for the info everyone!

2/11/2018 9:33:36 PM

NE Arkansas

This has been a great read to learn from, Thanks guys

2/18/2018 10:19:47 AM

On a cliff in the desert

How would growing a tall sunflower next to your house or garage and letting it grow on your roof work? I don't have a tall stepladder or scaffolding.

2/18/2018 12:40:13 PM

Lewistown,IL

Wile coyote, The guys in the UK do just that. I have seen a ton of pictures of them growing the sunflower next to the house and using it for support.

2/18/2018 10:30:40 PM

On a cliff in the desert

I was wondering if the plants would damage the shingles on my roof. I just had my shingles replaced last fall. I have architectural shingles.

2/19/2018 10:32:04 AM

Lewistown,IL

The UK guys grow them on the ends of the structure. Some I have seen are two stories tall. Just to be clear I never seen them attach anything to the roof (shingles). Possibly run or attach a pole to the end of the house at the highest point.

2/19/2018 11:25:17 AM

On a cliff in the desert

I'll use hanging basket stakes to tie the sunflower to until its tall enough to be on the roof. That's what used when I grew Russian Mammoth sunflowers last year in my wife's flower garden.

2/19/2018 11:42:04 AM

Norfolk, UK

Great thread!

11/20/2018 1:55:26 PM