Study of hydroponics in cut flower production to increase water conservation and crop quality

Progress report for FW23-429

Project Type: Farmer/Rancher
Funds awarded in 2023: $25,000.00
Projected End Date: 11/30/2024
Host Institution Award ID: G280-23-W9210
Grant Recipient: Zack Family Farms
Region: Western
State: Utah
Principal Investigator:
Anna Zack
Zack Family Farms
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Project Information


There is an increasing demand for locally grown, sustainable produce, including cut flowers. In Utah, like much of the West, water availability is a major concern for farmers and this will likely only continue. While the benefits of growing locally are substantial, water use for conventionally grown flowers is increasingly unsustainable. 

Many vegetable growers (notably tomato, salad greens and hemp production) successfully grow high quality crops in controlled environments, but little research is available for floriculture. 

We seek to look at the feasibility of growing high-value crops, such as dahlias, hydroponically indoors to mitigate both the high water usage and pest and environmental pressures of field grown crops. Research species will include five common floriculture crops chosen for their profitability and species diversity: dahlias, snapdragons, cosmos, scented sweet peas and lisianthus. We will test the best methods for each crop grown, and compare water usage directly in conjunction with a field crop of the same variety. We will measure water usage, supplemental fertilization and amendment needs as well as the quality of the flowers with this research, focusing on stem number and length per plant, bloom size, and overall quality. 

Our goal with this research is to produce a product of similar or higher quality to field production, with significantly less water and land resources. If we are successful, we aim to share our methods and results with other growers to create a standard growing practice in places with low water availability, few land options, or challenging seasonal conditions for growing conventionally. We will disseminate our findings within our local flower community and extension office as well as nationally through the Association of Specialty Cut Flowers and make our information available online.

Project Objectives:

By studying the feasibility of growing floriculture crops hydroponically, we aim to test methods that could dramatically reduce water input while maintaining a marketable, local cut flower crop held to the same standards as conventionally grown cut flowers. Using this information we would share with other flower farmers the amount of water saved, hydroponic crop quality, costs involved, and best growing methods for specific crops. 


Research Seasons 2023 and 2024: largely the same, with initial fall data processing used to modify second season (if needed) and data processing in second year geared toward total research results. Conclusion of second season and data processing will prompt initiation of education plan, December 2024.

Date Activities Team Members
March Soil samples taken for baseline data; Seeds started in growth chamber; order supplies still needed for upcoming season; review season plan with TA; photo and documentation of process

PI: Anna Zack, TA: Dr James Cohen (Jim Cohen), Benjamin (Ben) Zack

Anna: Soil samples, seed starts, supplies

April Soil amendment applied based off of soil test; fields tilled for planting; drip line laid and tested; seedlings transplanted to larger seedling trays; Hydroponic setups installed, pumps and reservoirs tested; photo and documentation of process

Anna: transplants, field preparation. Documentation

Ben: hydroponic installation and equipment testing. Documentation

May Transplant seedlings in field and greenhouse when weather appropriate; mulch field rows; photo and documentation of process

Anna: transplant seedlings. Documentation.

Ben: Equipment running, routine and troubleshooting maintenance. Documentation

June Monitor plant progress, record findings; harvest and grade as flowers bloom; photo and document process

Anna: Plant care and harvest. Data collection and documentation. 

Ben: Equipment maintenance. 

July Monitor plant progress, record findings; harvest and grade as flowers bloom; photo and document process

Anna: Plant care and harvest. Data collection and documentation. 

Ben: Equipment maintenance. 

August Monitor plant progress, record findings; harvest and grade as flowers bloom; photo and document process

Anna: Plant care and harvest. Data collection and documentation.

Ben: Equipment maintenance. 

September Monitor plant progress, record findings; harvest and grade as flowers bloom; photo and document process

Anna: Plant care and harvest. Data collection and documentation.

Ben: Equipment maintenance. 

October Conclude research for season as frost date arrives; prep field and greenhouse for winter dormancy; photo and document process

Anna: Last harvest prior to frost date. Data collection and documentation. Pull drip lines, mulch and prepare farm for winter months. 

Ben: Remove plants from hydroponics, inspect and clean equipment, remove water and prepare for winter months. 

November Process all data collected for summer; season report created; plan and modify next season's research plan; order seeds and supplies for next growing season

Anna: Data processing, report. Modify plan for next growing season if needed. 

Jim Cohen: Review data processing, review report



Click linked name(s) to expand/collapse or show everyone's info
  • Dr. James Cohen - Technical Advisor
  • Benjamin Zack - Producer


Materials and methods:

Our research plan will compare field grown cut flower crops to hydroponically grown crops to compare water conservation and product quality between the two methods. 

Project site: We will grow on two sites for this project. The first site is our current farm field, where we will conventionally grow crops in 4'x50' raised soil rows. The second site will be an enclosed greenhouse structure outfitted with a hydroponics setup. Both sites will be located in Ogden, Utah. Both will have the same species and number of plants per species, seeds started and grown at the same time and season, and will be provided with the appropriate nutrient amendments, substrate, light, and water requirements for successful growth. 

Research design: We have designed our project using two commonly used commercial methods for growing hemp and vegetables hydroponically: the ebb and flow (or flood and drain system), and the nutrient film transfer system. There are a number of hydroponic methods in use, with ample research to demonstrate the best practices for growing specific food crops. We hypothesize that an ebb and flow model successfully used for hemp would correlate well with larger flowering plants such as a dahlias, that require large root space and plant support. For other crops, such as vines (e.g., tomatoes and cucumbers), we suspect that the nutrient film transfer method would have greater success, and we will implement it for vining sweet peas. Additionally, smaller herbs and greens crops commonly grown in nutrient film transfer systems correlate well for smaller cut flowers such as snapdragons, cosmos and lisianthus. By testing different hydroponic systems, we aim to find the greatest crop success for each species and identify specific needs for each crop. 

We will compare five common and valuable crop species: dahlias, snapdragons, cosmos, lisianthus, and sweet peas. These crops were chosen for three reasons: 1) their popularity among flower farmers, 2) marketable value and 3) diversity in growing condition requirements. All crops will be grown from seed with the exception of dahlias, which will be grown from cutting stock. Seeds and cuttings will be started in the same growth media at the same time for both the hydroponic greenhouse and the field to reduce variability in the test and control. An equal number of seedlings will be allocated to each planting group (field control, ebb and flow, and nutrient film transfer). Only healthy looking and uniform seedlings will be transplanted. 

The field control plot will be soil tested and amended based on soil test results prior to planting. Drip irrigation will be laid at 8" intervals along the 4'x50' raised beds, and will be covered with mulch for weed suppression and water retention. Plants will be transplanted on a timeline according to weather conditions and hardiness. Plants will be watered according to weather conditions and soil moisture meter readings. Additional soil amendments will be added as appropriate throughout the growing season. 

The greenhouse will have two hydroponic setups. The first will be an ebb and flow table, where water and liquid nutrient will fill a shallow table for 5-10 minutes then drain completely, repeating every 6-24 hours depending on plant size and water requirements. The plants will be grown in water-permeable containers sized to their mature growth and filled with soilless substrate. The second hydroponic setup will be a nutrient film transfer setup, where channels are pumped with a small, continuous supply of water and liquid nutrient to passively flow through plant roots. The plants will be grown in mesh baskets placed directly in the channels. Both systems will be tested twice daily for water pH level, salinity and nutrient content, and will be adjusted accordingly. 

Plants will be evaluated from the time of transplanting into the field or greenhouse up until post-harvest storage. We will use a visual qualitative grading scale to determine overall plant health weekly, observing growth, leaf size and color, disease symptom presence/absence, and insect or environmental damage if any. Once flowering, we will add flower qualitative grading, recording flower size and color vibrancy, as well as any defects from disease or insect/environmental damage present. We will also record quantitative values to measure number of stems, stem length at harvest, percentage of marketable blooms of total, and days to maturity. Once harvested, we will store a portion of the flowers in a floral holding solution in a cooler according to post-harvest best practices. We will record longevity in cold storage to determine any differences in transport ability and vase life. 

In addition to overall plant and flower quality, we will also monitor water and nutrient usage. In the field, drip lines will be metered to calculate gallons used over the season. Typical water-conservation measures we take in our field will be implemented, such as shade cloth and mulching. Amendments will be recorded as they are used. Greenhouse water and nutrients will be contained in a 200 gallon tank, with water levels measured at time of water testing to monitor water usage. Additional water added will be metered to calculate gallons used over the season. Nutrient will be supplemented as water testing indicates, and will be recorded. 

Our research will be conducted over two growing seasons: 2023 and 2024, typically May through September for northern Utah. A two-year study will account for normal variation in year-to-year growing conditions. We will collect data throughout the growing season to be analyzed once the season completes in the fall. We will use our data to compare specifically the number of usable stems, overall bloom quality, and water usage between hydroponic and field grown. Additional information collected will compare nutrient requirements, plant health, cost of production, and labor intensity needed to effectively grow the crop. For quantitative and qualitative traits, we will use a Wilcoxon-Kruskal-Wallis test to examine statistically significant differences between treatment and control, and collectively, data will be explored with multivariate methods, such as principal components analysis (PCA).

Participation Summary

Research Outcomes

Recommendations for sustainable agricultural production and future research:

In our first season we focused on the possibility and practicality of growing cut flowers hydroponically. We used NFT channels to grow cosmos, sweet peas, snapdragons and lisianthus flower species and used an ebb and flow table to grow much larger dahlias. Setup of the equipment proved challenging due to significant shipping delays, and once we had all of our materials we spent much of the spring season fine tuning pumps and sensors, finding the appropriate flow rate for our setup and each flower variety and the correct dose of liquid nutrient. We grew one single succession of all plants species simultaneously, starting in early June to harvest stage and mirrored the same species in the field plot. We found that cosmos grew exceptionally well in NFT channels and stem length and sturdiness were very similar to field grown. Snapdragons did similarly well, however the stems were thin. We will trial them again this growing season in spring and fall in addition to summer to see if greenhouse temperature was a factor, and will also grow them in soilless substrate in the ebb and flow table to compare. Sweet peas initially grew well but very few blooms of quality were recorded. This is very likely due to the temperature of the greenhouse as these are cool weather species. We have started our 2024 cool season crops, and sweet peas are being started now in March and will be again in August to see if spring/fall harvests are improved over high summer. Lisianthus grew initially very well with very strong looking plants but did not produce stems or flowers of a reasonable quality. We are looking into nutrition ratios for both lisianthus and sweet peas, and will grow lisianthus in both NFT channels and ebb and flow table this season to compare. We had moderate success growing dahlias with the ebb and flow table. The plants were healthy and large, with attractive blooms on long stems. They produced less blooms compared to the field. Our comparison field plot grew typically of a mid-season in Utah, needing daily watering and experiencing moderate insect pressure but with good production. We had shorter than typical lisianthus stems but had good bloom quality, and uniform snapdragons and cosmos. Sweet peas in the trial plot also did poorly in the heat, although outperformed the greenhouse by more than double. The dahlias grew well with tall stems but had significant loss due to insects in late summer.  With the exception of the occasional grasshopper caught in the greenhouse there was zero insect pressure and no plant or bloom damage from insects in the hydroponics greenhouse.

Looking forward into this growing season, we will implement the modifications listed above and compare water usage in field and hydroponic production. We will implement succession planting over a long season to accommodate both cool weather growers and heat loving species and will continue to compare quantity and quality of blooms produced between field and hydroponic greenhouse. Some considerations that may have affected our first research season were seasonality of plants, temperature of the field and greenhouse, nutrient ratio preferences and water flow rates. 

Education and Outreach

Participation Summary:

Education and outreach methods and analyses:

To date, we have not applied any outreach methods. We intend to supply in person and digital information dissemination at the conclusion of our study, and beyond speaking with grower peers in our area do not intend to provide any outreach before the completion of our study. 

At the completion of our study we intend to use the approaches 1) in-person discussions, 2) digital video information dissemination, and 3) plain language literature to target our research to our regional community specifically and are eager to also extend it farther to others interested in hydroponic floriculture.

Education and outreach results:

We have not conducted any outreach objectives, and as such until the completion of our study will not have results on our outreach findings. We are eager to process our data and share our information, but want the data be analyzed and completed prior to outreach to avoid any premature findings. 

Education and Outreach Outcomes

Recommendations for education and outreach:

We intend to disseminate our final results at the conclusion of our 2 year study. We will put out a fact sheet of our findings and recommendations, and intend to provide it in both spanish and english. We will also offer our results to both the Utah Cut Flower Farmers Association as well as to the Association of Specialty Cut Flower Growers. 

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.