Farmer-Led Trials Program Spotlight: Perkins Good Earth Farm
Tackling Aphids from the Inside Out: Nutrition, Sap Analysis, and Tomato Health
Written by Mary Hathaway, OFRF’s Research & Education Program Manager, and Dan Perkins, FLT Program participant
This project at Perkins Good Earth Farm will evaluate whether foliar nutrition can improve tomato health and reduce aphid pressure through proactive nutrient management. Results from this study will help organic vegetable growers better understand the impact of timing on aphid interventions.

Farmer Dan Perkins with his backpack sprayer.
Dan Perkins farms at Perkins Good Earth Farm, a certified organic, diversified vegetable operation that utilizes no-till, permanent deep-compost beds. Located in De Motte, Indiana, they grow produce and 18,000 bulbs of hardneck garlic for a 200 member CSA, on-farm stand, commercial kitchen, and local wholesale accounts.
In addition to their garlic focus, Dan has spent years refining his approach to high tunnel tomato production, guided by a commitment to proactive plant health management and ecological balance. His farm includes five high tunnels dedicated to tomato production, each featuring long east-west beds that support intensive, season-extended growing.
With an eye toward both soil health and market quality, Dan is invested in understanding the connection between plant nutrition and pest resilience. His work with sap analysis and customized foliar feeding reflects a broader vision: growing crops that are nutritionally robust, naturally resistant to pressure from pests, and consistently high in quality for his customers.
A Proactive Approach to Aphids
For many high tunnel tomato growers, aphids are a recurring and costly challenge. For Dan Perkins, the question has never simply been how to eliminate aphids, it’s been why are they there in the first place? Dan’s approach to pest management is rooted in plant physiology: the hypothesis that plants with well-balanced nutrition are inherently less attractive to aphids. Specifically, Dan has observed that plants with elevated free nitrates, which can signal nutritional imbalance, may be more susceptible to aphid colonization, as those compounds serve as a ready food source for the insects.
Dan has been exploring sap analysis as a proactive diagnostic tool, likening it to “blood work” for his tomato plants. Unlike standard soil or tissue tests, sap analysis captures a real-time snapshot of what nutrients are circulating within the plant, identifying imbalances before visible symptoms appear. Working with Advancing Eco Agriculture (AEA), Dan formulates customized foliar sprays based on sap analysis results that deliver chelated ions directly to plant tissue to rapidly correct deficiencies and support overall plant immunity.
This integrated approach of reading the plant, responding with precision, and then measuring the result, reflects Dan’s broader farming philosophy. Rather than reacting to pest outbreaks after the fact, he wants to understand the nutritional conditions that allow aphid populations to take hold, allowing him to intervene earlier and more intelligently.
On-Farm Trial Plan

This figure shows the randomized tomato plots being used in the trial.
With technical support from OFRF, Dan is conducting a randomized, replicated trial in his propagation house to investigate how the timing of sap analysis-guided foliar feeding affects aphid populations, yield, and tomato nutrient density. The trial uses 84 ‘Cuba Libre’ indeterminate slicer tomato plants arranged across two adjacent beds, with three treatment groups: a control (no foliar spray), an early spray (first application approximately two weeks post-transplant), and a late spray (first application at the economic threshold for aphid damage). Each treatment is replicated four times across plots of five plants each, with buffer plants sprayed with the early treatment to minimize drift between plots.
Sap samples will be collected before and after each foliar application across all treatment groups to track changes in plant nutrition and support the development of a predictive nutritional model. Aphid populations will be monitored weekly by a designated farm team member, using a consistent method of flagging representative infested leaves at the top, middle, and bottom of the three central plants in each plot. Yield will be tracked by marketable grade (A and B) and unmarketable categories. Fruit samples will be submitted for nutrient density analysis through an outside lab. The design also includes a built-in flexibility: if aphid pressure warrants a second spray in the early group, those plots can be converted to an “early + late” treatment, providing a practical real-world comparison of proactive versus threshold-based intervention.
Trial Updates

Dan planted ‘Cuba Libre’ slicer tomato plants across two adjacent high tunnel beds.
“I applied for the FLT program to conduct research on specific production challenges on my farm. Additionally, being part of a cohort of other farmers sounded fun; farming can be lonely, so connecting with other similarly-minded farmers is important. Working with Mary and Heather has been like having my own research support team. They ensure I stay on task during the busy season and that my questions get answered in a rigorous and valid way.”
– Dan Perkins, FLT Program Participant

Two buffer plants are placed in between spray groups.
This is part of a series of blogs highlighting farmers who are participating in OFRF’s Farmer-Led Trials program. Farmers receive technical support to address their production challenges through structured on-farm trials. To learn more about OFRF’s Farmer-Led Trials Program, visit our website page at https://ofrf.org/research/farmer-led-research-trials/
To learn more about Sap Testing visit ask.ifas.ufl.edu/publication/CV004
To learn more about Perkins Good Earth Farm visit perkinsgoodearthfarm.com/




































Rachel was motivated to implement conservation practices to reduce the risks associated with irrigation costs, one of the biggest concerns on her farm. During the very hot Arizona summers, Rachel can spend up to four hours a day hand-watering her crops. Not only is this time-consuming, but because she operates an urban farm that’s reliant on city water, it can be expensive. She is also passionate about
At Little Lighthouse Farm, soil health was restored because of the years of research on the benefits of cover cropping. Better soil health allows Rachel to grow better crops, which provide nutritious products to community members. Research funding makes this all possible and demonstrates that innovations in organic agriculture research can result in widespread adoption of beneficial practices, helping farms of all sizes and production types meet conservation goals. And the benefits of research extend beyond the farm, too. According to an analysis done by the USDA Economic Research Service (ERS), every $1 invested into agricultural research triggers a 







