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Conventional Seed Treatments And R.O.I

Why Treat Your Seed?

In my earlier post I covered what might be available as a seed treatment for a certified organic grower.  The reason I took the time to do this was that a client of mine found themselves in this exact situation where they heard me touting the returns that other clients of mine were getting by treating seeds before planting started like those you can find here:  And, he thought that by virtue of being NOP compliant that he was precluded from treating his seeds.

I realized that I haven’t really gone into the reasons why treating your seeds is something that is desirable in the first place, so here is my “primer” on what I’ve found out over the last couple of years of working with this technology.

High Return On Investment

I was listening to a podcast by a grower into promoting nutrient dense crops and he made the statement that the highest ROI you can get for fertilizing annuals is with conventional commercial seed treatments.  Although he is a commercial grower of salad greens and tomatoes, he didn’t distinguish what kind of crop he was talking about, and he didn’t elaborate on “why”, so I will do some reasoned speculation here to explain why.

Little Waste

One of the reasons for the high returns on investment is that it takes very little material to cover the seeds that will be employed across an entire acre.  If you are going to broadcast chemicals or biologicals across an entire acre there is a lot of soil that will never interact directly with a plant’s roots — even once the crop is reaching full maturity.

That is what led to the idea of “banding” fertilizer.  Banding is where someone puts a smaller sized, concentrated, strip of fertilizer, usually just outside of the active root zone of a crop and lets the plants’ roots extend into the zone of concentrated fertilization.  The idea is to maximize the amount of fertilizer that gets taken up by the crop in the given year that the fertilizer is put down and to minimize nutrient tie-up that happens with charged particles of fertilizer interact and combine with oppositely charged particles in the soil profile.  The resultant compounds are insoluble in water and unavailable to a plant’s roots.

Treating the seed with an element of fertility is an “extreme” version of banding.  To the extend that the fertility can be absorbed into the seed’s shell or coat, there is little to no waste as all the nutrition can be utilized by the seed during the germination process.

The amount of product used can be as little as 4 to 8 ounces of liquid to cover the seed that would cover an acre, or the approximate size of a football field. Imagine spreading half a can of soda across an entire football field and getting the product evenly spaced enough to be able to effect each plant in that field.  Now you understand the power and rational of treating your seeds.


NOP-Compliant Seed Dressing

Primer On Seed Dressings

The objective of every seed treatment is to enhance seed performance in one or more of the following means:

  • improve germ rates. In conventional cultivation, seed is frequently dressed with synthetic fungicides which minimize seed and seedling losses due to seedborne and soilborne attack.
  • eliminate seed-borne microorganisms or protect from soilborne microorganisms, and
  • optimize ease of taking care of and reliability of planting (reduce gaps in stand or the need for thinning of plants, particularly when mechanized planters are utilized),

Most seed protectants are not necessarily an option for certified organic growers; however, there are some seed treatments, such as priming, pelletizing, and the use of hot water or NOP-compliant protectants, that can be used by certified organic farmers to boost seed performance.

Certain plants are superior prospects for seed treatment due to the nature of the seed (irregularly or small shaped) or the designated production system (conventional versus organic). For instance, pelleted seed is useful in head lettuce production due to the need for accurate seeding, but is less beneficial for dense sowings of looseleaf lettuce in bed cultivation.

All-Natural Seed Treatment Options


Primed seed has absorbed just enough water to dissolve germination inhibitors and activate the early stages of germination. Primed seed is therefore in a suspended state of growth, so it germinates faster and more uniformly over a broader temperature range, reducing the likelihood of thin or very thick plant stands.


A seed pellet is a coating, usually of clay mixed with other inerts, that streamlines the size, shape, and uniformity of a small, non-round seed such as those of lettuce, carrots, onions, and many herbs and flowers. Ideally, the pelleting materials are somewhat permeable to oxygen and absorb water quickly so that the pellet splits immediately upon hydration.

Seed Health Treatments

This is a broad category of treatment options that includes warm water, biological and plant extracts, bleach disinfection, and biologicals (microbes). These treatment methods can improve seed and seedling health by eliminating seedborne microorganisms from the seed or protecting germinating seeds from attack by soilborne microorganisms.

Hot water treatment

The use of hot water treatment option to eliminate seedborne diseases, particularly those caused by plant pathogenic bacteria, is well-established. While the technique does not work for large-seeded vegetable crops, it has proven effective for brassicas, carrots, peppers, and tomatoes, and, to a lesser degree, celery, spinach, and lettuce.

Pro tip: While there are some general guidelines that put the heat around 120 degrees F and the time around 20 minutes to complete the priming and cleaning of the seeds, try experimenting a little bit as some seeds may prove more sensitive to heat than others.

Hot water treatment can cause a reduction in vigor over time, so hot water treated seed should not be kept for longer than a season. Only fresh seed of high vigor should be subjected to hot water treatment method, as old seed or seed of low vigor may respond poorly to the stress of the treatment method and have reduced viability. Hot water treated seed should be used within one season; the storage life of the seed may be reduced by the treatment method.

Oils and Plant Extracts

Evaluating plant extracts and oils as seed treatment options is a new research area so there is currently little data on their efficacy. Plant oils such as thyme, cinnamon, clove, lemongrass, oregano, savory, and garlic show some potential to suppress damping-off, and thyme oil is in use in Europe as a seed treatment option. Pure soybean or mineral oils have been shown to reduce storage molds of maize and soybean. Further research on the disease suppression potential of these oils is necessary to determine the viability of essential oil-based seed treatment protocols.

Clorox Treatment

Bleach can be used to surface-disinfect seeds as an alternative to hot water. Bleach will eliminate pathogens on the seed surface but will not eliminate pathogens beneath the seed coat.

Biological Seed Treatments

Biological seed treatment options, alone or in conjunction with priming and pelleting processes, may have potential in some situations for improving plant health. In studies evaluating the efficacy of these microorganisms as seed treatments or drenches, results have been inconsistent.

In Summary

The purpose of any seed treatment method is to simply to improve the seeds’  performance in one or more of the following ways:

  1. get rid of seedborne microorganisms or protect from soilborne pathogens
  2. optimize ease of handling and accuracy of sowing (reduce gaps in stand or the need for thinning of plants, particularly when mechanized planters are used), and
  3. improve germination rates

Most seed protectants are not an option for all-natural producers; however, there are some seed treatment methods, such as priming, pelletizing, and the use of hot water or NOP-compliant protectants, that can be used by all-natural growers to improve seed performance.