Abstract: Observing the vegetative growth of Humulus lupulus ‘Cascade’ over the course of three weeks in two growing methods. Plant 1 will be grown in a store bought Miracle-Gro Aeroponic system, and Plant 2 will be grown in potting soil. Both plants will be grown indoors and will be administered artificial light from a LED light that is built into the Miracle-Gro Aeroponic system. Both plants will be watered from the same source and pH will be recorded; as well as given the same amount of liquid fertilizer over the period of recorded time. Throughout the three weeks both Hop plants progress will be documented through measurements, photographs, and other visible observations. The goal of this experiment is to see which method will allow the Humulus lupulus ‘Cascade’ to exhibit the most vegetative growth of the documented period.
Objective: Will Humulus lupulus ‘Cascade’ exhibit faster growth indoors with artificial light, in an Aeroponic system or in potting soil.
Hypothesis: The Humulus lupulus ‘Cascade’ that will grow in the Aeroponic system at a faster rate than the other in potting soil.
Humulus lupulus, Hops, is classified as a perennial vegetable and is widely known for providing the flavouring and preservative used in beer (Crawford, 119). Hops is a part of the plant family Cannabaceae alongside Cannabis. Both of these genuses boast similar visual, aromatic, and medicinal similarities that people have taken a liking to (Eyck, 30). The plant is dioecious and the female plant produces the cones containing acids and oils used in beer brewing. These cones produce a resin called luptulin, which is made up of essential oils and alpha & beta acids. These acids are what give beer its distinct bitterness and/or aroma. Each hop variety has its own particular balance of acid levels that can also vary from year to year (Eyck, 34). There are over two hundred varieties of hops, including Humulus lupulus ‘Cascade’ the best-selling American-grown hop known for its strong aroma (Hieronymus, 74). Cascade’s aroma characteristics are medium intense floral, citrus, and grapefruit like tones (Eyck, 44). Its acid levels are 4.5-7% alpha, 4.8-7% beta and contains a total oil content of 0.7-1.4% (Hieronymus, 143).
Hops that are grown outdoors do best between latitudes 30º and 52º. They require 15 hours of daylight, 120 days with no frost, and 6-8 weeks of dormancy below 40º F (Hieronymus, 89). Hops are typically grown and propagated from rhizome. The reasoning for this, is that it hops are heterozygous and by propagating asexually this ensures the same genetic plant is being grown (Eyck, 32). A hop plant is capable of growing 40 feet under ideal conditions in one grow season. Its roots can reach depths of 15 feet and its rhizome can reach 5 feet in length (Eyck, 31). A hop plant will produce shoots that will need a support system. The plant binds around these support systems, and in the industry growers have trained the apical meristem to bind around things such as rope, trellises, walls, and bamboo. The secret to its binding ability is in hops’ trichomes which allow it to barb in to whatever it chooses to support itself with and climb (Eyck, 33-34). Female hops typically produce their cones in midsummer and once harvested at maturity they will be cut back and left to go into a dormant state for the winter. Cascade is known to reach maturity medium to medium-late in the season and yield a harvest of 1,800 to 2,000 pounds per acre (Eyck, 44).
Hops are not typically grown indoors because of cost reasons. But as technology progresses and movements like vertical farming, urban gardening, and hydroponics continue it may become more popular in the future. Currently in the USA hops are primarily grown in the pacific northwest of the country, since their climate and soil is ideal for hop growing (Artist). Growing indoors allows for a controlled environment. Where things such as temperature, lighting, and air flow can be programed. It also separates what you are growing from pests and diseases that can be obtained outside. Vegetative and bloom cycles can be altered as well since you are regulating the light schedule. Indoor growers use a variety of mediums to grow in from potting soil to water and various lighting units such as halogens and LEDs. These are things that can be expensive and make indoor growing not cost effective. LEDs are rumored to be reducing in price as technology advances. For indoor growing LEDs are ideal as they are extremely efficient and can be tailored to certain wavelengths (McEwan).
No know research currently seems to exist for Hops being grown in an Aeroponic system but proof exists of it has been grown hydroponically. Aeroponics is a version of hydroponics, growing plants without soil in water. What Aeroponics is defined as is plant grown in a chamber of air and nutrients were roots are suspended and misted with water periodically (Cervantes, 410-11). This way of growing is fairly new and wasn’t developed until 1985 when Richard Stoner made the first patent (Cervantes, 410).
One study does exist that observed plants grown in a variety of hydroponic formats, including Aeroponics. Plants with rhizomes such as ginger were used and did not respond well to being in a nearly entire wet environment. The conclusion was that further research will be needed in creating a hydroponic system that would be more ideal to maximize rhizome biomass productions (Hayden, 536-38).
Materials and Methods: For the purpose of this experiment each plant will be shortened to H1 (the Aeroponic grown Humulus lupulus) and H2 (the potting soil grown Humulus lupulus). Upon obtaining H1 and H2, they will immediately be transferred into their planned medium. Each plant will be given water from the same source, tap, and a pH reading will be recorded. On day one they will be given a mild 4mL amount of fertilizer (Miracle Gro Liquid Plant Food, 4-3-6) to reinforce growth. Each plant will be set under the supplied LED light apart of the Miracle Grow Harvest system and supplied 16 hours of artificial light for every 24-hour day. Both plants’ height will immediately be recorded. From that point on H1 and H2 will be periodically observed (every 2-3 days) and height will be measured and documented as well as any new developments in growth habits. Photographs will be taken in order to compare and contrast further changes. When needed the LED light will be adjusted so it will not burn the plants’ leaves. Water will be given to H2 when needed and the Aeroponic system’s water will be changed when needed. On the 16th day of the experiment both plants will once again be given the same fertilizer dosage as before in order to continue reinforcement of healthy-expedited growth. On the 20th day the experiment will be concluded and the recorded data will be analyzed. The primary piece of equipment used in this experiment will be the Miracle-Gro AeroGarden Harvest. It is essentially a compact Aeroponic garden unit advertised as a house-hold unit that grows plants five times faster than soil. It features one 20 watt LED unit and several concealed misters that spray water and nutrients from a water reserve that plant roots are submerged in (AeroGarden)
Results/Discussion and Conclusions:
H1: Water based Aeroponic system (Miracle-Gro Harvest)/LED
Water pH: 7.2 (tested 3/29).
Temperature of Room: 60 degrees Fahrenheit.
Planted, fertilized (4 mL of Miracle-Gro Liquid Plant Food, 4-3-6).
Height Recorded: H1- 3.1 inches
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H1: No noticeable changes, Height recorded: 3.1 inches
H2: No noticeable changes, Height recorded: 2.8 inches
H1: Noticeable leaves have begun to appear (bigger than H2/ darker shade of green), Dominate terminal bud. Height: 3.6 inches
H2: Noticeable leaves begin to appear (smaller than H1/ lime green color), Dominate terminal bud. Height: 2.8 inches
H1: Two ‘twin’ shoots are developing/ competing. Broader and bushier foliage has developed. Height: 5.2 inches
H2: Plant has surpassed H1 in nearly every way. Main shoot has shot up and broader leaves have grown. Two lower shoots are also making an appearance. Watered. Height: 6.8 inches
H1: The shoots have extended and new leaves continue to appear as well as broaden. No new shoots have appeared. Height: 8 inches
H2: Plant continues to surpass H1, and tripled in height since last documented. Several new shoots have appeared and old leaves have grown broader. The apex shoot/stem has begun to show its vine characteristics as it hugs the nearby law for support. Height: 18.1 inches
H1: Fertilizer (M.G. 4-3-6) added to system. Third shoot has emerged. Continued growth of two prior shoots, they are both beginning to ‘crawl’ out. Height: 13.5 inches
H2: Roping was installed to support plant. Growth is continuing at a vigorous rate. 6 shoots have been counted from the main stalk; as well as 1 new shoot emerging from the soil. Plant was watered and fertilized (M.G. 4-3-6). Height: 23.6 inches
H1: slight discoloration in leaves noted. One of the ‘twin’ shoots is reaching outward from the LED light, while the other is reaching toward the LED light alongside H2. Height: 17.5 inches
H2: Plant has completely outgrown this system and is in need of transplanting. The apex shoot has begun to wrap itself around the string installed to support it. Discoloration in leaves, especially larger leaves noted. Possible Burning from LED, or from outgrowing plastic pot. Lesser shoots are reaching out in all directions and new shoots continue to emerge. Height: 34 inches.
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Day 20 (4/14) End of Experiment.
H1: Discoloration is waning in leaves observed on previous day; they’re beginning to look healthy once more. No new shoot growth, continued growth of ‘twin’ shoots. Height: 22 inches
H2: Discoloration continues in main shoot’s leaves. Other shoots are expanding further out. Height: 40.5 inches
H1’s Height H1’s Growth Difference From Previous Day H2’s Height H2’s Growth Difference
Day 1 3.1” 0 2.8” 0 Day 4 3.1” 0 2.8” 0 Day 6 3.6” .5” 2.8” 0 Day 10 5.2” 1.6” 6.8” 4” Day 13 8” 2.8” 18.1” 11.3” Day 16 13.5” 5.5” 23.6” 5.6” Day 18 17.5” 4” 34” 10.4” Day 20 22” 4.5” 40.5” 6.5”
Both plants started off growing at the same moderate pace, and H1at first even showed signs of being the faster growing plant. Between day 6 (3/31) and day 10 (4/4) is when things began to significantly change. H2 took the lead and began to grow at immensely faster rate, while H1 grew moderately. From day 10 to day 20, H1’s slope when graphed was 1.7, while H2’s slope was 3.4. These numbers show that H2 completely doubled H1’s growth rate, with the difference between slopes being 1.7. On another note, when the fertilizer (M.G. 4-3-6) was added to both plants, H1 continued at the same rate of growth while H2’s rate bolted up. From day 1 to day 16 H2’s slope of growth was 1.4; however, after the fertilizer was added on day 16 the slope increased to 4.2 (day 16 – day 20). In comparison Hops when grown outside are estimated to grow a 1 foot a day (Eyck, 31). The closest the Hop plants in the experiment got to this rate was H2 between day 13 and day 16, were it grew 11.3 inches. This is not to say that under the right indoor conditions that these plants could have proven that, but due to the lack of equipment that would be needed to establish a successful indoor plant grow room as well as this being a study of juvenile plants in their first 20 days. This work should not be shown as a representation to doubt the effectiveness of indoor plant growing.
This experiment was a success and is an accurate example of Humulus lupulus ‘Cascade’ juvenile growth in indoor conditions. Both plants showed growth in the mediums they were placed in and adapted satisfactory to the artificial light that nurtured them. My hypothesis was proven wrong, due to the Hop plant that was placed in the potting soil medium becoming the more vigorous grower. The reasoning for this could be that H2’s rhizome could expand more in the soil medium than its counterpart in the Aeroponic system, or that the potting soil gave it more essential micro and macro nutrients that it needed to be a more successful grower. H1 was more contained within the Aeroponic system with its rhizome fitting in a hole the size of 1.5 inches compared to H2 in a 4-inch pot. Whether it be a space issue or an issue of the Hops’ roots not enjoying being submerged in water, these conditions were unable to be altered in the experiment. If this experiment were to be conducted again a more elaborate Aeroponic and lighting system would be needed. Both plants in their later days surpassed the maximum height the Miracle Grow Harvest unit’s LED light could extended upward. Because of this both plants in the later part of the experiment didn’t receive as much light as they received prior. This lighting issue may have also caused burning of both plants’ leaves, which was observed and documented in the log on day 18 – day 20. Population size is also a problem in this experiment. Since it was a problem of obtaining several candidates, only two were documented; one for each medium. Ideally, I would have experimented with 3:3 or at least 2:2, but that was unfortunately not possible. With several candidates in both mediums you avoid running into possible bad genetics within the plant itself, which is something that could have happened for not all plants are created equal. Regardless of the variables this experiment encountered, it does prove that Hops can be grown indoors under artificial light and that potting soil was the superior medium to a water based Aeroponic system for Hops in this incident.
Artist, Samurai. “Hydroponic Year-Round Fresh Hops Could Change Everything.” New School Beer. The New School, 02 Dec. 2015. Web. 17 Apr. 2017.
Cervantes, Jorge. The cannabis encyclopedia: the definitive guide to cultivation & consumption of medical marijuana. Vancouver: Van Patten Publishing, 2015. Print.
Crawford, Martin. How to grow perennial vegetables. Totnes, Devon: Green , 2012. Print.
Eyck, Lauren Ten, and Dietrich Gehring. The Hop Grower’s Handbook: The Essential Guide for Sustainable, Small-Scale Production for Home and Market. White River Junction: Chelsea Green Publishing, 2015. Print.
Hayden, Anita L. “Aeroponic and Hydroponic Systems for Medicinal Herb, Rhizome, and Root Crops.” Hortscience, vol. 41, no. 3, June 2006, pp. 536-538. EBSCOhost, libproxy.temple.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=puh&AN=21060537&site=ehost-live&scope=site.
Hieronymus, Stan. For the love of hops: the practical guide to aroma, bitterness, and the culture of hops. Boulder: Brewers Publications, 2012. Print.
McEwan, Gavin. “New Places to Grow.” Horticulture Week, 13 May 2016, pp. 29-30. EBSCOhost, libproxy.temple.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=puh&AN=115593345&site=ehost-live&scope=site.
“Miracle-Gro AeroGarden Harvest – Black – AeroGarden Harvest – AeroGardens.” AeroGarden Indoor Garden Store. Miracle-Gro, n.d. Web. 17 Apr. 2017.
Aeroponics for Humulus lupulus ‘Cascade’ Christopher LeClair 4/17/17 Abstract: Observing the vegetative growth of Humulus lupulus ‘Cascade’ over the course of three weeks in two growing methods.