Evaluating Ornamental Plants as Cut Flowers

Larry Johnson
Fair Field Flowers, Brooklyn, Wisconsin

A challenge in the cut flower business is to provide our customers with something “new” or “different”.  This trial includes five perennials (20 plants each) sold at a local specialty perennial nursery for use in a home garden or landscape setting. The trial will determine whether they can be used as “new” cut flowers in this area (southern Wisconsin – the new zone 5).
Perennials, by nature, take time to develop and so the results of the trial during this first year are limited. A short summary of each variety is provided below.

Origanum rotkugel (showy oregano)
This species has great promise as a cut flower. In fact, my wife liked them so well that she “snitched” several stems from the test plot for the house. The pink/purple flowers are on 18-inch stems with an average of four stems per plant (first year). They bloomed in late to mid July. Vase life was at least a week.  
Part of the trial is to evaluate the longevity of the plant relative to harvest intensity: will the plant come back strong next year after it has been cut? To test this factor the twenty plants were divided into four groups of 5 plants each. Group 1 – all stems were cut to the base. Group 2 – all stems were cut at 6 inches from the base. Group 3 – half of the stems from each plant were cut to the base, the other stems were left uncut. Group 4 – no stems were harvested, the plant will be allowed to regrow with no cutting. The plants are marked with flags to identify them next year.  We’ll see what happens.

Vernonia latissma (tall ironweed)
Tall ironweed is just now starting to bloom. The purple flowers are on stems averaging 36 inches long with about three saleable stems per plant. The plants were partially shaded and received limited water. They’ll be moved to a better location next year.

Persicaria virginiana (Compton’s form)
The green and purple foliage has done well this year. The red whips are beginning to form.  Some of the leaves will be cut to test as a foliage product. The stems with leaf damage will be saved to evaluate the flowering whips.

Gaura lindheimeri ‘Summer Breeze’
Gaura takes a while to develop as a viable cut flower. The first-year airy stems are unusual and appealing; however, it would take stems from all 20 plants to make one decent bunch. The plants should continue to develop and the stems should become more numerous in coming years.
Lespedeza thunbergii ‘Gibraltar’ (bush clover)
So far, this plant has been slow to develop, maybe because it was planted in partial shade, – the only “dry” place ready when the plants were ready. Critters dug/pulled out some of the plugs, too. A better location next year will likely provide better results.

Exploring Low-Tech Possibilities for Heating Hoophouses with Compost

Diane Szukovathy
Jello Mold Farm, Mount Vernon, Washington

Every fall and winter we make loads of 160-degree hot compost using fish scrap, alder sawdust and farm debris. Last fall I applied for an ASCFG Grower Grant because we were constructing our first hoophouse and I’ve always wondered if there might be a low tech and practical way to harness the heat from the compost piles to help boost shoulder season crops.
My objective was to build a system which would circulate water through tubing in the compost pile where it would gather heat and then disperse it in pipes laid at ground level next to crops in the hoophouse. Crops chosen for study were sweet peas, ranunculus and anenomes. I wanted to see if I could measure differences in crop timing, quality and yields by taking heat from the compost pile and releasing it at the root zones of the crops.
The part of this experiment I thought would be difficult – building a pump system – turned out to be fairly straightforward. I purchased a rain barrel, a 2600 gph submersible inline pond pump, and laid 300’ of 1/2:” PVC piping at ground level in my hoophouse beds. I plugged in the pump and the recirculating system worked like a charm, sending water first through tubing in the compost pile, then through the PVC pipes and returning water to the barrel with a reassuring gentle stream. Sweet music!
Everything to do with harnessing heat from the compost pile, however, has tried my undauntible farmer optimism. Initially I thought to use copper tubing in the pile because it would facilitate quick heat exchange. So I buried a very snazzy contraption made from about 450’ of 1/4” copper tubing into a two-yard pile of fish scrap and sawdust and dead dahlia foliage. Every morning I eagerly checked my compost thermometer and waited and waited and waited but my pile simply would not heat. Cursing did not help. So I rebuilt the pile using more nitrogen and still it didn’t help. It would heat to about 82 degrees and stop. Hard not to take this personally.
After a few more tries at making the pile go, I noticed that the edges of the pile were heating, but not the center, stuck a thermometer in the corner and read that it was 50 degrees hotter than the center of the pile. I can only guess that either the mass of my contraption or the fact that it was made from copper, or both factors were keeping the pile from heating properly. So I rebuilt the pile larger using 250’ of 3/4” rubber hot water hose. Within three days the pile had heated to 158 degrees. It was a highlight of my geek life to switch on the system and see that the water in the pipes had heated to 105 degrees!
The water stayed hot for about two minutes and then dropped down into the eighties. The compost pile temperature dropped from 158 degrees to 132 degrees in four hours of continuously running the pump and was in danger of shutting the pile down entirely. So I purchased a percentage timer that would run the pump for a couple of minutes to circulate the warm water, then shut the pump off to give the pile a break for about eight minutes. I believe with a five-yard pile this system will work well.
By this time it was March and I didn’t have time to collect data from my crops this year. Meanwhile I took a look at a latitude map of northern Washington State and realized we are farther north than much of the state of Maine, meaning that we have very short days in fall, winter and early spring. Since many shoulder season crops are daylight sensitive as well as responsive to soil temperature, I plan to add daylight hours using supplemental fluorescent lighting on a timer as well as heating the soil with the compost pile. I also plan to expand the crops I study to include lupine, stock, sunflowers, and campanula.
As I write it is late August. Flowers are abundant everywhere and demand isn’t that high. If we can get even a few weeks of crop acceleration during the time of year when there are hardly any locally grown flowers available, especially Easter and Mother’s Day, it could make all the difference for us in profitability for our farm.

Use of Gibberellic Acid for Extending Stem Length, Increasing Stem Count and Cold Substitution in Various Cut Flower Crops

Becky Devlin
Back Bay Flower Co., , Virginia Beach, Virginia

In November 2007, I submitted an application for an ASCFG Grower Grant. In my southern coastal zone 8 climate of Virginia Beach, our brief springs days morph quickly into 90 degree summer weather, and by the time we start pulling out our sweaters and embracing fall, winter seems to have arrived. Because these seasonal changes are so fleeting, fall-planted plugs have a brief window in which it’s cool enough to be planted and still leave enough time to be well established before a frost hits. Likewise, spring flowers need to be timed well: planted only after the temperatures are warm enough, but soon enough to bloom before the heat takes over and snuffs them out. These factors make it tough to get nice, long stems and big blooms on many spring-planted or even some spring-blooming crops.
So, in search of magic, I applied for a grant to support research that would test the use of gibberellic acid –  a substance derived from naturally-occurring plant growth hormones – on various cut flower crops to increase stem length and/or stem count, and vernalization substitution. I had used GA3 successfully in the past to increase stem length in sinuata statice after reading about its use for substitution of vernalization, or cold period. I also wondered why it isn’t used more, since it’s a natural substance and easy to use.
I ordered my GA3from Peaceful Valley Farm Supply, as I had in the past, for about $80 for a small jar (about 1 cup, maybe). The white powder is so concentrated I had to dig deep in my math skills to convert the large numbers on the dilution charts I found in order for dilution to be correct for my 5-gallon sprayer.
Here is the conversion information I found:  “The basic stock solution of 1000ppm is prepared by dissolving GA3 in water at a rate of 1mg in 1 ml. Therefore, a 100mg packet is dissolved in 100ml of water or a little less than 1/2 cup (0.42 cup), a 500mg packet in 500ml (2.1 cups), or a 1000mg in 1000ml water. Ummm….yeah. Sure.
Believe it or not, I eventually figured it out for my research. And wrote it down. With a Sharpie.
According to JL Hudson Seeds, gibberellins are regularly used in agriculture to decrease or increase fruit set, delay fruit aging, and aid in seed germination. These effects are highly dependent on concentration and stage of plant growth. For example, ten micrograms of GA3 applied to pea seedlings nearly doubled shoot length if applied at 3 days old, but barely affected 9- day-old seedlings. GA3 is also used to trigger flowering of sweet potatoes in breeding programs and to help tomatoes set fruit at high temperatures in the tropics.
So, with all this fabulous scientific mumbo-jumbo dancing in my head, I planned on planting:
• Spring-flowering sweet peas and hoophouse-grown late winter/early spring flowering sweet peas, summer field-grown Karma dahlias and fall hoophouse-grown Karma dahlias, early spring-planted elatum and belladonna delphinium, ‘Foxy’ foxglove, ‘Champion’ campanula, and lisianthus (early-, mid- and late- blooming varieties). All were to be sprayed with various concentrations (400, 600 & 800 ppm, 1 and 2 applications each) of gibberellic acid once well established.
• I also planned to use two different control groups of all but the sweet peas and the dahlias: one spring-planted with no GA3 applications, and one fall-planted (vernalized) with no GA3 applications. Stem length, bloom size, number of stems and bloom time would be recorded for all groups.
Of course, “planned” is the key word. I submitted my grant application in November.  I received my approval – and check – in December. So excited about actually receiving a grant and anxious to deliver results, I made some calls to order plugs asap. I ordered everything except the foxgloves, which weren’t available, only to find it too cold to plant the plugs when they arrived. I bumped them up to larger cells and kept them in the hoop until I could get them planted. In hindsight, I should have waited until the following fall to get started since it ended up being March before they could go in the ground safely.
In addition, I was having a massive rodent problem in my greenhouse. Mice were digging up and eating both seeds and seedlings as fast as I could plant them. I reordered seed 2-3 times from September to March and gave up on a few crops that needed to go in the ground in fall or early spring, with sweet peas being one of them. At my wits’ end, I finally direct-seeded some sweet peas to make a last-ditch effort to have a crop that spring. They came up, but by the time they started to flower, our temps shot up to 92 and stayed for a few days. It was just enough to send them to seed after only one application of GA3.
I have since gotten cats on the recommendation of other growers on the Bulletin Board and have no mice on my entire 7 acres!
I had a similar situation with campanula and delphinium; both were planted too late, and bloomed short when temperatures shot up. Karma dahlias also went in late, as plugs weren’t available until June, which was just the right time for the beetles to start snacking. Needless to say, my research did not go as planned.
The following year I had planned to start from square one, but was up to my knees in the organic certification application process for the first time. When fall rolled around, I was afraid to order and plant any plugs for fear of not qualifying for organic certification (annual plugs have to be certified organic and perennials have to be grown for one year to be considered organic). Another grower had told me that if non-organic plugs were planted in a field that some certifiers may not consider that entire field for certification for 3 years. Until I had straight answers from my certifying agency, I was afraid to plant anything I had not grown from seed. By the time my certification was complete and I had answers, it was again too late to order or plant any plugs.
While the whole plan sounded fabulous to me on paper and in theory, it hasn’t exactly been smooth sailing. We had moved our hoophouse in the summer of 2007, so the rodent problem was new and not something I could have foreseen. My enthusiasm about the project itself caused me to jump the gun a bit on getting started and the organic certification process threw off all of our systems a bit last year. But, now that I’m back on track, the cats are at play and we have a year of being certified (and I know the rules) under our belt, I’m ready to roll. Plugs are already being planted to (finally) repeat the research study now, and hopefully I’ll have solid results to report.