Article written by: Jason Danaher Ph.D.
The seasonality of specialty crops is crucial for their optimal growth and economic viability of the cropping system. By aligning planting and harvesting with the right times, farmers can ensure crops have the ideal conditions to grow, such as proper temperature and photoperiod, while ensuring revenue is maximized. This alignment helps to improve crop quality, yields, and reduce the risk of losses from disease. Understanding the climate and weather patterns of your specific region is crucial in determining which crops are suitable for each season, as different crops have different temperature requirements. You should check with your local extension office to determine optimal planting schedules for your region. The following link provides the University of Florida’s Institute of Food and Agricultural Sciences recommendations for optimal seasons of vegetable crops grown outdoors in soil-based systems in the state of Florida.
Florida Gardening: Suggested Planting Schedule For Soil-Based Systems
But, having an indoor aquaponic system can allow for environmental control and production of specialty crops out of season; therefore, extending the growing season and resulting in a better market price for the producer over soil-based cropping systems with limited growing seasons. A key aspect to achieving success in controlled environmental agriculture is the production of healthy vegetable transplants. The production of good quality vegetable transplants (Figure 1) is essential for optimizing crop growth and maintaining aquaponic production system efficiency. High quality vegetable seedlings can be expensive to produce (i.e. materials and labor), so buying and planting the correct quantity of seeds along with planning out the space requirement to produce the required quantity of transplants is important. The good news is some simple calculations can be used to help in the planning and production process.
Figure 1. Recently germinated seedlings grown in soilless substrates for aquaponic vegetable production.
The following calculations will assume the small aquaponic facility has a staggered plant production plan with a weekly harvest from a portion of the system. After harvest the farmer will require 1,056 transplants each week and each specialty seed packet contains 650 seeds. We will also assume the germination rate of seeds is 92% and 80% of the germinated seeds will grow into a quality seedling 28 days after seed planting. The farmer is using a standard 1020 plant tray with dimensions 11.0” x 21.4” and a 72 square cell propagation tray. Let’s get calculating!
1) First, the farmer requires 1,056 transplants each week and the seeds have a germination rate of 92%. How many seeds need to be planted to compensate for the germination rate?
2) Second, the farmer knows 80% of the germinated seeds will grow into a quality transplant. How many seeds have to be planted to ensure not only good germination, but also enough quality transplants are available 28 days later?
Now the farmer knows 1,435 seeds are needed weekly to account for the germination rate and percent of germinated seeds reaching optimal transplant size 28 days later.
3) Third, he or she needs to determine the quantity of seed packets required to supply 1,435 seeds weekly.
4) Next, the farmer calculates the quantity of 72 cell propagation trays required each week.
Because the farmer will not be cutting and altering tray dimensions, he or she will round up the result to the nearest whole number; therefore, the farmer will plan on a weekly transplant production area requiring 20 trays.
5) The farmer now needs to calculate the required space the 20 trays will occupy in the nursery area.
Each week of transplant production will need 32.7 ft2 of growing area. Twenty-eight days or 4-weeks of transplant space will require four times the area. The 32.7 ft2 represents one-quarter the space requirements; therefore, a total of 131.0 ft2 is required to produce the required quantity of transplants on a weekly staggered production cycle for the aquaponic system. The following are some tips for storing your seeds to ensure the quality is maintained for ideal germination rates and growth in the future. Store seeds in their original packet so seeds are easily identified for future plantings. Keep opened packets in a cool, dry place with low humidity. An airtight container or plastic bag in a refrigerator works well. Keep the seeds away from heat (>90oF), out of direct sunlight, and in an area free of rodents. Open packets of vegetable seeds are generally viable up to 1 year in a proper storage environment without affecting germination rates. Closed packets of vegetable seeds stored in a proper environment are generally viable up to 2 years or longer from their packaging date depending on the vegetable type. Feel free to call Aquatic Equipment & Design, Inc. staff at 407-995-6490 or email info@aquaticed.com if you have additional questions on planning your transplant production.