Two sunflower plants on nine-inch centers produced the highest share of heads under four inches across, and the lowest share above six. That is the spacing result Celeste Scott wants to replicate this season, and it came out of three years of University of Tennessee trials built around what Tennessee growers were already doing.
Scott (Commercial Horticulture Specialist, West Tennessee, UT Extension) and Natalie Bumgarner (Associate Professor and Extension Specialist, University of Tennessee) ran a specialty crop block grant project in two locations six hours apart, Knoxville and Jackson. Fertility came first: one pound of nitrogen per thousand square feet for low, two for medium, three for high, delivered as 20-10-20 through a Dosatron, on University of Maryland numbers, the only guidance for the region. Zinnia stem counts trended up as nitrogen rose. Zinderellas culled the hardest. Queeny Limes have to come off at peak color or they look dingy in July heat.
Celosia showed its clearest fertility response in the plume types. Two years of Jackson celosia data went in the bin after early planting, root bound transplants, and off-target herbicide from the next plot over.
On the market side, about 62 percent of surveyed consumers were buying for gifts, 40 percent or more called it an impulse, and half knew they wanted flowers only when they saw them. Willingness to pay rises with the share of local flowers in the bouquet. Five warm season enterprise budgets are built for a quarter acre.
Recorded July 23, 2026 at the second annual Cut Flower Symposium, hosted by the UGA Center for Urban Agriculture with the Georgia Green Industry Association. Segment 3 of 8. Runtime 30:30. CEU Categories: [PENDING].
Chapters
0:00 Recorded Introduction: Bumgarner and Scott
0:56 A Multi-State Program, and How Tennessee Got Here
3:13 The Specialty Crop Block Grant and What It Funded
4:11 Building the Trials Around What Growers Grow
5:15 First-Year Scope and the Data That Overwhelmed Us
6:13 Fertility Treatments and the Maryland Baseline
7:19 Zinnias: Zinderellas, Benary’s Giants, Agaves, Queenys
8:59 Jackson Zinnia Results and Why They Read Lower
10:14 Zinnia Takeaways: Nitrogen, Culls, Harvest Timing
10:56 Celosia Types and the Knoxville Fertility Data
12:34 Why the Jackson Celosia Data Was Thrown Out
13:28 Celosia Cultivars: Sunday Green to Kurume
14:37 Sunflowers: From Fertility to Spacing
15:29 Three Spacing Treatments, Six-Inch to Nine-Inch
16:39 How Spacing Changed Flower Head Diameter
18:34 Sunflower Takeaways and the And More
19:40 Trialing Summary and Production Guides
20:01 Marketing: The Grower and Consumer Surveys
22:05 When and Where Consumers Buy
24:04 Barriers, Willingness to Pay, and the Budgets
26:03 Closing and Handoff to the Moderator
26:38 Q&A: Leaf-Footed Bugs on Sunflowers
28:04 Q&A: Where to Start, and What to Plant
Questions Answered
Which sunflower spacing produced the most usable heads?
Scott compared one plant on six-inch spacing, two plants on six-inch centers, and two plants on nine-inch centers. The nine-inch pairing gave the highest percentage of heads under four inches petal to petal and the lowest percentage at six inches and above. Single plants on six inches produced a high share above six inches, which is less versatile for mixed bouquets.
Which celosia cultivars performed?
Sunday Green for reliably long, thin stems, which matters when fasciation leaves a beautiful bloom on a stem too thick to use. Flamingo Feather as a filler with very long stems and a reliable re-bloom several weeks after a hard cut. Pampas Plume for quality and versatility. Kurume, an older cultivar, for a smaller coxcomb form.
Any organic option for leaf-footed bugs on sunflowers?
Scott saw most damage on foliage, not heads, and harvesting on time means the petals are not fully expanded yet. If pressure warrants control, horticultural oils and insecticidal soaps need excellent coverage, leave little residual, and can cause phytotoxic issues in warm season heat.
Where should a new grower start?
Warm season cut flowers, mostly easy from seed, in a mix of filler, foliage, and focal: zinnias, celosia, gomphrena, Frosted Explosion, ornamental millets, and basil, cut only after the stems feel woody. Bumgarner notes the UT budgets are built for a quarter acre across five cultivars, since nobody starting out needs an acre of zinnias.
Resources
UT enterprise budgets, five warm season annuals, quarter-acre basis: QR code shown at 25:36, no address spoken on the recording
Production guides from the trial work: in preparation as of July 2026
University of Maryland cut flower fertility guidance: the low, medium, high basis for the trials
UT Center for Profitable Agriculture, Pick Tennessee Conference, and a state growers association in development
Cut Flower Symposium · UGA Center for Urban Agriculture · Georgia Green Industry Association
Platform Note (not part of the pasted description)
Length. Everything from the opening line through the footer above measures 4,974 characters, inside YouTube’s roughly 5,000-character description field. That is 26 characters of headroom, far tighter than segment 02’s file, and the cause is the chapter list rather than the prose. Re-count after any edit, however small.
All 23 chapter markers are kept. Each was verified against a block start time in the corrected transcript at Stage 2. A viewer scrubbing a half-hour talk for the celosia cultivar list or the spacing result needs them more than a sixteen-minute talk does, so the character budget was found in the Q&A instead.
Eight of the twelve Q&A pairs were cut. Four carry over. What went, and why:
| Cut pair | Reason |
|---|---|
| Why run trials in two locations | Knoxville and Jackson are named in the lede, six hours apart, and the site difference is not load bearing at this length. |
| What fertility rates, and how delivered | The rates and the Dosatron are in the lede paragraph verbatim. Repeating them as a pair spends 400 characters on ground already covered. |
| Did zinnias respond to added nitrogen | The trend line is in the lede. The Benary’s tradeoff and the reason Jackson read lower are on the website version. |
| Which zinnias gave them trouble | Zinderellas and the Queeny Lime harvest window are both in the lede. |
| What happened to the Jackson celosia data | The failure is in the lede. The full account, including the herbicide drift and the root bound transplants, is on the website version. |
| Why they stopped testing fertility on sunflowers | Setup for the spacing answer, which stands without it. |
| Where growers sell versus where consumers buy | The longest answer in the package and the hardest to shorten without losing the grocery store contrast. Kept whole on the website version. |
| How the purchase decision gets made | The three headline figures are in the lede paragraph. |
All twelve pairs are in the website version. The four kept here are the two chat questions plus the two results a grower would come to this recording for, the sunflower spacing outcome and the celosia cultivar list.
Attribution held through the condensing. This is a two-presenter segment and the condensed answers keep the same split as the Stage 2 package: Scott for the Jackson plots, the trial design, the cultivar takeaways, the sunflower spacing work, and both chat questions; Bumgarner for the Knoxville data, the surveys, and the budgets. No result is credited to the wrong site or the wrong speaker.
No web address is printed, because none was spoken. Bumgarner shows a QR code for the enterprise budgets at 25:36 and never reads a URL aloud. Unlike segment 02, there is nothing here the audio sweep could recover. The budget link has to come from the speakers or the symposium organizers, and the Resources block above says so rather than inventing one. This is the one item that must be filled by hand before publishing.
Timestamp format is M:SS and MM:SS throughout, since the segment runs under an hour.
Scaling Note
Target. Stage 3 derives from the Stage 2 package and scales with it, not with ambition. The segment 02 YouTube file ran 8.8 KB against a 15.7 KB archive summary, a ratio of 0.56. This segment’s archive summary is 18.2 KB, so the proportional target was about 10 KB.
Delivered. 10.4 KB, of which the pasted description is 4,974 characters. The description cannot scale with runtime, because YouTube’s field is fixed at roughly 5,000 characters, so a talk nearly twice as long gets the same budget spread across nine more chapter markers. That is why four Q&A pairs survive here against segment 02’s five: same character ceiling, more chapters competing for it. The overage sits in the Platform Note, which is not pasted anywhere.
What was not scaled. The chapter list. All 23 markers are kept at full length. Cutting chapters to buy prose would make the file worse for the one job a YouTube description does on a half-hour recording.
Processed for UGA Center for Urban Agriculture / Cut Flower Symposium Archives
Source: Stage 2 Archive Package, GTBOP_Archive_Summary_2026-07-23_BumgarnerScottUTResearch.md
Chain of custody: corrected SRT (Stage 1), GTBOP_Transcript_2026-07-23_BumgarnerScottUTResearch.srt (402 blocks), verified against Natalie and Celeste.mp4 at 1830.719 s