Abstract:
A device and method that uses the application of light to retard the wilting and spoilage of cut flowers. The lamps used can direct focused illumination in the targeted wavelengths known to positively and optimally affect the viability of different types of cut flowers, hi the most preferred embodiment, an LED light source is positioned to direct light upwardly toward the flowers, either from a base structure upon which a vase holding the flowers and having a transparent bottom surface is placed, or from a position within an opaque vase holding flowers that is substantially below the flower stems. Optionally, light can be directed from the side or overhead, but such a configuration is not optimal. Side-by-side testing confirms that flowers exposed to the light lasted more than a week longer than those not having the added illumination.

Description:
TECHNICAL FIELD 
       [0001]    This invention relates to flowers, and more particularly to containing cut flowers so as to lengthen their useful life. 
       BACKGROUND 
       [0002]    This invention relates to the field of preserving cut flowers, specifically to a device and method for extending the vitality of cut flowers so they can be maintained in a fresh looking condition during transport, while on display prior to sale, and for an extended period of enjoyment by the consumer after sale, without the flowers experiencing premature wilting, browning, fading in color, or otherwise spoiling.* 
         [0003]    Cut flowers have a limited shelf life, and are adversely affected by elevated temperatures, drafts, low humidity, vibration, and other environmental factors. Many cut flowers must be disposed of unsold due to spoilage in transit and while they are on display prior to sale. Attempts have been made to prolong the usable life of cut flowers during transport, so that they arrive at their destination while still looking fresh and viable and in condition for display and sale. Flower vendors also attempt to prolong the usable life of cut flowers as much as possible while they are on display prior to sale to attract a good customer response. Consumers expect at least 3-4 days for the shelf life of purchased cut flowers. Consumers are displeased when they bring home cut flowers, unwrap and place them in fresh water, only to have them unrecoverably wilt and/or turn brown on the first or second day. 
         [0004]    Irrespective of the means used to prolong the useful life of harvested flowers, they inevitably will wilt, fade in color, and often turn brown. The time period before such wilting occurs is widely variable. It depends in part upon the variety of flower, the length of time since it was originally cut, the type of transport and storage employed between cutting and use, and the ambient conditions to which is subjected during transport and display. While cold temperatures are known to extend the life of cut flowers, most people&#39;s homes are not kept sufficiently cold to optimize the life of cut flowers while they are on display. Also, for flower wholesalers and vendors, commercial refrigeration is expensive. Frequent changing of the water into which cut flowers are placed, frequent making of fresh cuts in the stems, and the adding of chemical preservatives to the water in which freshly cut flowers are placed, are other commonly used ways in which to extend the life of cut flowers. However, each of these methods of cut flower preservation is either labor intensive or expensive, or both, and none extends the viability of the cut flowers for more than a few days. In contrast, the present invention at least doubles life of cut flowers meaning the time cut flowers maintain a fresh, presentable appearance, and viability is extended more than two weeks longer in some instances, than identical test flowers not subject to the present invention light. 
         [0005]    Another means of prolonging the shelf life of harvested plant material is disclosed in U.S. Pat. No. 5,464,456 to Kertz (1995). The Kertz invention employs a pulsed electrical field around a plant or portion of a plant during handling, shipping, and marketing of cut flowers, greens, and trees, to prolong their freshness, and also uses the same pulsed electrical field to promote plant growth in non-harvested plants. An aspect of the present invention is extending the usable life of cut flowers in a manner providing ease of implementation and cost-saving advantages compared to the pulsed-electrical field technique of Kertz. 
       SUMMARY OF THE INVENTION 
       [0006]    The primary object of this invention is to provide an effective means of prolonging the viability of cut flowers, including but not limited to roses, in many cases for at least a week longer than untreated flowers in a normal home environment. A further object of this invention is to provide a means of prolonging the viability of cut flowers that is reusable, easy to use, and requires minimal maintenance between uses. It is also an object of this invention to provide a means of prolonging the viability of cut flowers that is not labor intensive or cost prohibitive. It is a further object of this invention to provide a means of prolonging the viability of cut flowers that is made from durable materials for long-term use. 
         [0007]    As described herein, properly manufactured and used, the present invention is a family of devices and methods that uses the application of light sources to direct effective, preferably optimal, wavelengths of light toward cut-flower stems to retard their inevitable wilting and spoilage. The LED lamps or chips predominantly used can direct focused illumination in the targeted wavelengths determined to positively and optimally affect the viability of different types of cut plants, specifically flowers. Also, a suitable controller can be used to select plant-specific wavelength regimens determined to optimize the preservation of particular flower species. 
         [0008]    The apparatus and method of the present invention preferably uses LED lamps or chips to direct focused illumination in the wavelengths determined to positively and preferably, optimally affect the viability of different types of cut flowers. However, any lamp with a filter or that otherwise can produce the needed wavelengths for cut flower preservation can be used. Typically, the LED light or other alternative light source is positioned to direct light upwardly toward the cut flowers, either from a base structure upon which a container, which we refer to for convenience as a vase, holding the flowers and having a translucent or, preferably, transparent bottom surface is placed, or from a position within a transparent or opaque vase holding flowers that is generally at the lower end of the flower stems, wherein the stems are illuminated. The foliage may also be, but not need not be, illuminated. The light can be directed from above or the side, although this will not be the optimal configuration. Also, a small watertight unit with integral battery and light could be placed in the bottom of a vase, varying in diameter with the size of the vase. 
         [0009]    We have found that for roses the concentration of dissolved oxygen remains higher in the water of those whose stems are subjected to light from a red LED (650 nm plus or minus 5 nm) as compared to untreated roses. In the alternative, other light sources and lamps in combination with wavelength-selection systems, for example, filters, can be used to provide the needed wavelengths. In the most preferred embodiment, the LED light source is positioned to direct light upwardly through a vase in which the stems of cut flowers are held, either by use of a vase having a transparent bottom to hold the flowers placed upon a base structure supporting a light source able to produce the needed wavelength of light, or when an opaque vase is used, the light source is placed into a position within the vase that is generally near to the lower end of the flower stems. An immersable light with integral battery can be placed in the bottom of a vase before adding the water and the flowers. The foliage may also be illuminated. Side-by-side testing with LED light sources confirmed that cut flowers exposed to the light source lasted more than a week longer than those not having the added illumination, and some flowers even lasted more than two weeks longer than identical untreated cut flowers in specific environmental conditions i.e. conditions known to reduce the viability of cut flowers such as low humidity, and high heat will also negatively impact the effect of the light. Experiments indicate that even in the harshest environment with ambient of temperatures above 90° C., the light at least doubled time of flower viability. The test set up is described below. 
         [0010]    We have also tested orchids, which are notoriously delicate and short-lived as cut flowers. We have shown that, similarly to longer lived roses, the useful life of orchids as cut flowers can be doubled, from 2-3 days to 5-6 days, by shining red light on the stems at intensities achievable with available LEDs. Significant improvement of cut-flower useful life has also been shown in trials with irises, carnations, tulips, daisies and chrysanthemums. All of these cut flowers, like roses and orchids, have longer useful lives when red light was shone on their stems (alone or in combination with blue and/or green light). 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  presents in elevation a vase sitting upon a base containing an LED chip light source, with a light source positioned adjacent to the stems of the cut flowers, with battery or outside supply. 
           [0012]      FIG. 2  presents in elevation a vase sitting upon a base containing a source of white light and a filter. 
           [0013]      FIG. 3  is a perspective view of the immersable version of the light source. 
           [0014]      FIG. 4  is a cross-section of the device of  FIG. 3 . 
       
    
    
       [0015]    File numbers in the figures refer to like elements. 
       DETAILED DESCRIPTION OF THE INVENTION 
       [0016]      FIG. 1  depicts a preferred embodiment of a base for use with transparent vases for holding cut flowers. Transparent vase  8  contains water  12  and cut flowers  10  whose stems are immersed in the water. Of course, any desired additive can be included in the water. Supporting vase  8  is base  4 . Base  4  contains LED light source  6 . Light source  6  is in visual communication with the bottom of vase  8  and, thus, with the stems of flowers  10 . thus, any protective cover over the light source is translucent or, preferably, transparent (see  FIG. 4 ). Light source  6  is alternatively powered through power cord  7  to an external electrical source (not shown) or batteries  15  insertable in base  4 . It is not required that base  4  include both power sources; only one power source is required. Switch means to turn light source  6  on and off (not shown) will be included. A surface-mounted mechanical switch may be utilized, as may an internal switch operable by wireless remote control. Light source  6  may have a selected, fixed wavelength. Alternatively light source  6  may have selectable wavelengths. Powered by either electrical source, light source  6  illuminates the stems of flowers  10  with light of a selected wavelength. 
         [0017]    With light shining upwardly as shown in  FIG. 1 , foliage, if any, of flowers  10  will also be illuminated to at least a minor extent. Alternatively, light source  6  could be supported above the bottom of vase  8  on base  4  located so as to be adjacent to a lower portion of the vertical side of vase  8  so as to shine light across the stems of flowers  10 . Use of a colored transparent or translucent vase results in some filtering of incident light, as will be appreciated. We prefer not to rely on colored glass to filter white light, however, because colored glass is a poor filter and an LED provides a much higher percentage of the desired wavelength photons. 
         [0018]      FIG. 2  shows another embodiment of a base for use with a transparent vase. As in  FIG. 1 , vase  8  sits upon base  4  containing light source  6 , with light source  6  positioned outside vase  8  and under it to direct light of specific wavelengths upwardly toward the cut flowers  10  held by vase  8  to retard their wilting and spoilage and prolong their viability during transport, storage, and display. Light source  6  may be used in addition to other viability prolonging means, such as a reduced temperature, a humid environment, or the use of chemical solutions prepared to maintain the hydration of freshly harvested flowers  10 . Further, while the drawings herein show light source  6  being supported by a base  4 , in the alternative, it is also contemplated for light source  3  to be placed within vase  8 , and such placement within vase  8  is required when the bottom of vase  8  is opaque. 
         [0019]    The embodiment shown in  FIG. 2  differs from the embodiment of  FIG. 1  described above in the nature of light source  6 . Base  4  in  FIG. 2  contains a white-light source  6  and filter  9  for selecting the wavelength of light to be projected through vase  8  to the stems of flowers  10 . In other respects the design of base  4  is as described in connection with  FIG. 1 . 
         [0020]      FIGS. 3 and 4  depict a preferred embodiment of a self-contained drop-in unit  3  according to this invention. Unit  3  is conveniently circular in planar cross section to conform to cylindrically shaped vases, but any shape may be used, as long as light can be directed into stems of flowers in a vase containing unit  3 . As better shown in  FIG. 4 , unit  3  comprises water-tight case  14 , which includes transparent lens  13 . Within case  14  are light source  6  and its batter power source  15 . Unit  3  may include a reclosable watertight door (not shown) for batter replacement. Alternatively, unit  3  may be a disposable unit without a door for batter replacement. Light source  6  is positioned so as to project light upwardly through lens  13  such that, when unit  3  is placed in the bottom of a base, light will shine onto stems of cut flowers placed in the vase. 
         [0021]    Light source  6  can be imbedded within base  4  or unit  3 , as long as the base or unit is made from transparent or translucent materials. In the alternative, base  4  or unit  3  can be made from materials having any decorative color and or surface texture or design, as long as it has transparent or translucent inset (or lens). Also, if it is contemplated for base  4  or unit  3  to be reusable, access must be provided for light source  6  or at least battery replacement. In place of batteries, or in addition thereto, it is contemplated for a power cord and plug ( 7 ) to be used to bring electrical power to light source  6  so that it can provide the needed illumination for retarding the premature wilting and spoilage of cut flowers  10 . Although an LED lamp or chip with multiple LED lamps is preferred for light source  6  due to its compact configuration, ease of use, and convenience in selecting a desired wavelength for optimal cut flower shelf life, it is also considered to be within the scope of the present invention for light source  6  to include any type of lamp, including incandescent and fluorescent bulbs, as well as any other lighting means that in combination with filters or other wavelength selecting devices can be employed to direct light of a targeted wavelengths toward cut flowers  10  to retard their wilting and spoilage. Should some light sources  6  other that an LED lamp or chip with multiple LED lamps can generate a significant amount of heat, means preferably will be included to wisk or direct any such heat away from the cut flowers so it will not have an affect on their viability. Thus, the size, shape, and or surface appearance of the light source  6  shown in the drawings is not intended to be limiting, but instead are merely provided as examples of a light source  6  usable to prolong the viability of cut flowers. Further, the size, shape, and or surface appearance of the base  4  shown in the sole drawing herein is not intended to be limiting, but instead is merely provided by way of example. When light source  6  is placed within vase  8 , base  4  is not required. Further, although not shown, it is also considered to be within the scope of the present invention for base  4  to provide any batteries, activation switches and/or wireless communication needed for the activation of light source  6 . Also, when light source  6  is placed within vase  8 , its outer housing needs to be water-resistant and non-corroding. Embodiments of the present invention may be disposable or reusable, with disposable embodiments having a predetermined amount of battery power calculated in hours, days, weeks, or perhaps a month. Then, instead of the labor intensive process of purchasing, recharging, and/or installing replacement batteries, and cleaning the base  4  or unit  3  devices between uses materials could be used to make the base or unit last for a predetermined period, but not be so durable as to be usable for extended or multiple repeat use. Bases  4  and units  3 , particularly disposable embodiments, may be sold in an enclosed but closeable state, wherein closure by the purchaser activates the light source. For example, a twist or screw closure of a case portion may complete an electrical circuit and constitute a switch to turn on the light source. 
         [0022]    Ascertainment of light wavelengths useful (that is “effective”) in the method of this invention, that is, wavelengths that at least double the time a cut flowers species is suitable for display, and ascertainment of the optimum wavelength for a flower species, is routine. We prefer a simple test apparatus and method for this purpose. The apparatus comprises a series of bases  4 , each in a test position separated from other test positions by black barriers. We prefer to utilize variable wavelength light sources  6  commonly powered externally through a landscape lighting transformer. We have used graduated cylinders of clear (transparent, not colored) glass as the container (“base”). In addition to periodically measuring certain parameters, we prefer also to include a camera for record purposes. A digital camera permits images to be stored on a computer along with test measurements. 
         [0023]    Light sources for several positions are adjusted to illuminate the vases with light of several different test wavelengths. Periodic measurements may include water uptake, using the cylinder gradations, oxygen reduction potential, using a commercial pocket tester, dissolved oxygen, using a commercial meter, ambient air temperature, and water temperature. Care should be taken to assure that all test positions are exposed to the same ambient conditions, particularly temperature, humidity and natural light. 
         [0024]    We have conducted trials with roses, orchids and other flowers with the apparatus generally shown in  FIG. 1  utilizing clear, cylindrical vases of 4-inch (10.2 cm) diameter. As the light source we have used three LED light sticks, each containing 10 red LEDs, 12 blue LEDs and 20 green LEDs. If none of the LEDs is disengaged (off), white light results. Colors are obtained by disengaging one or more of the LED colors. Red is obtained by disengaging the blue LEDs and green LEDs. Blue is obtained by disengaging the red and the green LEDs. Green is obtained by disengaging the red and the blue LEDs. Yellow is obtained by disengaging only the blue LEDs. Magenta is obtained by disengaging only the green LEDs. Cyan is obtained by disengaging only the red LEDs. Intensity for each color (including white) is obtained by disengaging none, one, two, or all three (the no-light controls) of the light sticks. The LEDs in the light sticks we utilized had the following peak wavelengths: red, 640-650 nm; green, 520-535 nm; blue, 450-465 nm. Our tests have shown that, as long as red light is included at a level significantly above ambient room lighting, a significant improvement, measured days by whole numbers, is obtained in the useful life of cut flowers. We have also tested deep red LEDs, having wavelength maxima in the range of 600-680 nm and found them also to give significant improvement. 
         [0025]    Utilizing optimization-by-trial as described above with particular flower species, including roses, we have determined that light of 650 nm LEDs works effectively and quite well, as stated above. That light is in the red range, nominally in the range of 625-725 nm. By repeating the test with different wavelengths in the red range using variable sources or by using a number of different LEDs in the red range, an optimum wavelength can be determined. Finding optimally effective red wavelengths for other flower species of flowers and determining the optimum wavelength can be routinely ascertained by experiments described above. Useful red light may extend down to 600 nm wavelength. We have determined this by using white fluorescent light as the red light source. The wavelength of the red phosphor was found to have a peak of about 611 nm. Significant extension in useful life was obtained. Also, the spectrum of a red LED having a maximum at 640 nm shows that the peak actually begins at around 600 nm and ends at about 670 nm. 
         [0026]    As shown in Example 2 below, we have investigated the minimum intensity of red light being applied. Significant benefit was noted (sample 33% magenta) at a level estimated to be 10 mW for a 4-inch (10.2 cm) diameter circular base. This translates to 10 mW applied over 12.6 square inches, or 0.8 mW/in 2  or 0.12 mW/cm 2 . Our preferred minimum intensity is twice the foregoing, namely, 20 mW (milliwatts) for a 4″ diameter circular base. This translates to 0.24 mW/cm 2  of application area. 
         [0027]    The type of light source preferably is LEDs. However, neon, fluorescent and incandescent sources, or even low-power laser sources, can be used, as long as the source has a significant emission in the red range and as long as heating is avoided or compensated. For example, an incandescent light source is not preferred, because the heat output from such sources would require inclusion of means to prevent heating water in the vase (container holding the cut flowers) and the flower stems, typically a means to cool the container. 
       EXAMPLES 
     1. Effect of Wavelength 
       [0028]    The apparatus was generally as shown in  FIG. 1 . The light source was LED light sticks as described above. Vases used were 4-inch (10.2 cm) diameter cylindrical clear, transparent glass vases. The test flowers were white roses, six in each vase in approximately 8 inches (20 cm) of water. Each light emitting base contained three operating light sticks as described above, except that, of course, the no-light control contained no operating light stick. Light blocks were used to isolate each vase from the others. The room in which the trial was conducted was air conditioned. Room lighting was kept on except on weekends. 
         [0029]    The eight samples included, in addition to the no-light control, seven colors obtained by disengaging selected LEDs as described earlier: red, yellow, magenta and white, for all of which red LEDs were not disengaged, and green, blue and cyan, for all of which the red LED&#39;s were disengaged. 
         [0030]    Over a 13-day trial we monitored on a daily basis the appearance of the cut flowers to see when they wilted sufficiently to be considered not useful any longer as cut flowers, the appearance of the leaves, and the clarity of the water in each vase. We performed certain tests—amount of water used, amount of dissolved oxygen, and oxidation-reduction potential, but judgments were made on appearance. 
         [0031]    We found that by the controlling criterion of flower appearance (not wilted to the extent of being judged unacceptable for display as cut flowers), the vases subjected to red light, either red LEDs alone or the combinations of yellow, magenta and white, gave significantly longer useful cut-flower life than did the no-light control (that is, ambient room light only), or samples subjected to light other than red, namely, green, blue and cyan. By day 9 the no-light sample was wilted. By day 13 the blue, green and cyan samples showed considerable wilting as compared to the red, yellow, magenta and white samples. Overall we judged that the incident red light extended useful life by 2-3 days, when applied with our without blue light, green light, or both. 
         [0032]    A similar trial was performed in a room that was not climate-controlled and whose temperature reached 90° F. (nearly 38° C.) on occasion. The white roses in this trial appeared to be fresher than those used in the trial reported above. By day ten the differences were striking between the cut flowers whose stems received red light, alone or in combination (particularly magenta and white), as compared to cut flowers whose stems received no red light, that is, green light, blue light or green-and-blue light. The latter were beyond useful life, the former were not. This trial demonstrated a significant extension, measured in days, in useful life by use of red light, alone or in combination. 
         [0033]    Water clarity appeared to correlate with the difference in appearance of the flowers. The water in the vases subjected to red and red-containing light never turned cloudy, whereas water in the other samples did. 
       2. Intensity Range 
       [0034]    Using the same test apparatus described above, a trial was run with red light of varying intensities. Here again, six white roses were used per vase. Eight samples included, in addition to a no-light control, (a) three samples utilizing red LEDs of three light sticks (red, magenta, white), (b) two samples utilizing red LEDs of two light sticks (red, magenta), and (c) two samples utilizing red LEDs form only one light stick (red, magenta). The trial was continued for 19 days. 
         [0035]    Three observations were made: (a) when the majority of roses turned (wilted), (b) when the foliage appeared to have died, and (c) when the water turned from clear to cloudy. The no-light control gave results as follows: (a) 9 days, (b) 11 days, (c) 11 days. In contrast all the other samples gave results of at least: (a) 19 days, (b) 15 days, and (c) 19 days. Red light, alone or in combination and over a wide intensity range, were judged to extend useful life by about ten days over the no-light control. We did observe an anomaly in two samples, in each of which one of six flowers died much earlier than the other five. We suspect that these two flowers were damaged or had an embolism when they were cut. Otherwise the performance of the six flowers in each sample were reasonably uniform. 
         [0036]    While the description herein provides preferred embodiments of the present cut flower prolonging invention, it should not be used to limit its scope. For example, variations of the present invention, while not shown and described herein, can also be considered within the scope of the present invention, such as programmed variations in the wavelength of light used for cut flower preservation; the placement of the light source in or out of the vase; the type of light source or sources employed, and the number of light sources used. Thus, the scope of the present invention should be determined by the appended claims and their legal equivalents, rather than being limited to the examples given.