Stupid sunflower question

[Natty Dread]

I'm sure you master gardeners will laugh at me, but how does one grow a sunflower to be 6 feet tall? I've tried growing sunflowers from seed for the past two years, starting them in pots and transplanting the seedlings to containers outside when it gets warm enough, but the seeds I've planted have set one small bloom at about 18" and then nothing. (I haven't pinched or anything - I was always told that sunflowers are the easiest plant to grow, so I just planted 'em and watched 'em grow.) Are those huge Kansas-style sunflowers perennials that take a few years to get that tall? Any info appreciated!

Rhonda Richmond, VA USDA Zone 7

******** Basic human psychology is one of my subroutines.

[Doug Kanter]

Get a soil test. Either buy a kit and do it yourself, TWICE (in case of errors), or pay the very small price to have it done by your cooperative extension. You have to eliminate soil factors first, and then other reasons.

[Mark Anderson]

You need the Massive Sunflower seeds or something similar. Not all sunflowers are alike and many don't grow that big. I've gotten them 8' high growing them in a container with no problem. The sunflowers in my wildflower mixes only get around 4' high. The Menards by me has an entire section dedicated to different sunflower seeds producing plants of all different shapes and sizes.

In the following pic from early July last summer, these are 7' high grown in a 20 gallon Rubbermaid tote. They're volunteers from the previous years so they're part massive part some other breed made by the bees. The year before these were well over 8 feet high. I don't have to plant sunflowers anymore. :-)

[Callen Molenda]

Hi Rhonda,

I'm in Charlottesville, so we're practically neighbors.

I found that when I started sunflowers from seed they got too leggy, no matter what I did. Just sowing them directly into the bed after May 1st and then ignoring them works much better for me.

Of course, make sure your seeds are the really tall variety, too. There are so many different kinds out there and some of them are quite short. Callen in VA

[Chuckie]

There are no stupid questions. We all have to learn what we know at some point.

[Wolf Kirchmeir]

You get a variety that will grow that tall. :-) One such has been sold hereabouts as a Russian Sunflower, and has grown to over 8ft tall in my front yard. It has white seeds, not black or brown ones, but the birds don't care, they gobble them up anyway. I have no ides what other names it goes by.

[Hal]

at # 2548.

Regards,

Hal

[Natty Dread]

Well, in response to everyone that said get the variety that grow that tall, according to the seed packs I have, the varieties I've planted are supposed to grow to 6 or 7 feet in height. The problem is that mine have never gotten over 2 feet tall. The are leggy with thin stems and few leaves, not at all thick and full like the pictures Mark posted, for example. So do these plants actually grow 6 feet over one summer? How early in the season should I be planting them so they have sufficient grow time to get that big?

ND

[Timothy]

This sounds like a classic low nitrogen and or too little water issue. Sunflowers are somewhat heavy feeders and require a larger amount of nitrogen than you may think. You can deal with this issue in a variety of ways , one being to amend the soil with steer manure or blood meal. I like to plant sweet peas with my sunflowers. The peas will use the sunflowers as a trellis and help to feed the sunflowers. The peas will fade off in the summer heat and stop supplying the nitrogen and not affect the flower head production.

Sunflowers require lots of water. Sunflowers has been used for centuries to drain and reclaim swamp land in Holland. Under watering will stunt there growth just as badly as low nitrogen.

I would recommend that you amend your soil to at least 12 inches. Sunflowers will put out a massive root system if they have the room. Add compost, manure, blood meal..etc and a good handful or two of bone meal. Water well in the summer and you should have great sunflowers.

Good luck.

[Jim Elbrecht]

-snip-

I'm in NY & I grow Mammoth [a variety name] Sunflowers- plant them in mid May, and by mid August have had 10 footers with seed heads 2 feet across. [note that the page Hal posted has 'days to maturity' for many of the flowers- there are some 6footers there that say 60 days-- and others that need 100]

I'm with Tim- your problem is probably Nitrogen or not enough water. [mine seem to like well tilled soiled, too. Or maybe the ones in the well tilled soil are just better fed.]

Jim

[Garden Viking]

Go to Home Depot in Short Pump this weekend and see Kevin in garden.

[Jim]

Hi Rhonda,

I wonder if something might be stunting them during the starting and transplanting stage. I've grown huge sunflowers in zone 3 by direct seeding in the garden. Maybe a good test would be to direct sow a few at the same time you set out your seedlings. I'd bet a nickle the direct sown seeds will outperform.

$.02

Jim

[Andrew Ostrander]

I had 8 foot sunflowers last year, and will try for taller ones this year. The most important thing is the seed. If the parents were tall, yours will likely be tall. Many varieties of sunflower are short. Perhaps that's what you have.

I have found that starting them indoors in LARGE inverted drink cups and transplanting them to the outside has been most effective for me, because of my very short summer (latitude 50 N, zone 3) but if there is ANY root disturbance during transplanting the plants are set back and never really recover. In zone 7 I would work a lot of manure into their bed and just plant them outside well separated from each other.

Andrew