Healthy Soils Require Amendments
It is unrealistic to believe you can keep farming or gardening, and keep taking nutrients out of the soil without putting something back now and then. In the late 20th century, this was done with chemical fertilizers. No doubt, chemical fertilizers are still used today. When properly applied, qualified experts will argue that chemical fertilizers offer a critical nutrients essential for soil health. No arguments there by me.
In fact, with a nod to the organic growers that condemn all chemical products, I will assert that on occasion, I will find more living soil microbes and better overall soil health parameters in soils of conventional farmers who know how to manage their nutrients than I find on organic soils managed by growers who fail to replenish key nutrients. Farming simply isn’t as black-and-white as the terms “conventional,” and “organic.”
Chemical fertilizers typically include simple salts like ammonium nitrate or potassium sulfate. To be considered a complete fertilizer the three elements nitrogen, phosphorus, and potassium must all be present. This is an unfortunate legal definition because it implies that nitrogen, phosphorous, and potassium offer “complete” nutrition, but such is far from the truth. At least 17 elements are considered essential for plant growth. The soil microbiome requires these and others.
In addition to nutrients, soils require living organisms in order to support robust plant life. Crops in farms and gardens may also benefit from various growth regulators and many other substances that improve plant performance. Many of these fall under the category of biostimulants.
What is a Biostimulant?
To be truthful, this is a question that receives different answers from growers, scientists, regulators, and policy makers. In the most literal sense, a biostimulant is something that stimulates a biological process. Such a literal definitions doesn’t serve industry, government, and academics well, so they hold meetings and convene experts to arrive at definitions that work on labels. As a result, even experts in the production and distribution of biostimulants can’t always tell you what a biostimulant is.
Nonetheless, in a world concerned about growing demands for healthy foods and healthy soils, the question is drawing attention at local and global scales. Patrick du Jardin from the University of Liège recently tackled the need for a widely accepted definition by proposing that a biostimulant is “any substance or microorganism applied to plants with the aim to enhance nutrition efficiency, abiotic stress tolerance and/or crop quality traits, regardless of its nutrient content.”
In a recent EPA draft guidance, plant biostimulants are defined as “a relatively new, but growing, category of products containing naturally occurring substances and microbes that are used to stimulate plant growth, enhance resistance to plant pests, and reduce abiotic stress.” Furthermore, the EPA notes that biosimulants “do not provide any nutritionally relevant fertilizer benefit to the plant.”
Biostimulants are gaining popularity in both conventional and organic production systems, much like probiotics are gaining popularity in healthcare, simply because they offer big benefits when used properly.
The problem is, determining how to use biostimulants to achieve peak crop performance may take more effort than simply reading a label and following directions. Keep in mind that biostimulants work because of the partnerships that they make with plants and microbes. Like people, each plant and each microbe differs.
Anyone who has ever been part of a big family or a big office group knows that partnerships are complicated. When you find the perfect partners, you build Apple or Amazon together. When you force bad partners to work together, your life becomes the Office. The results you get using biostimulants can be equally complicated.
Just like there are some basic guidelines for building a good team, there are some basic guidelines for choosing effective soil amendments and biostimulants. If you understand basic soil health principles, such as those taught in Building Better Soils, it becomes easier to decide when a biostimulant may be appropriate.
When do you Need a Biostimulant?
Biostimulants can improve many aspects of plant performance. They can improve nutrient uptake, help plants resist freezing, drought, or heat waves, deter pests, and much more. In rare cases, a gardener is so proficient at replenishing the soil and creating a healthy ecosystem that his or her plants may not benefit from adding formulated products. In essence, these people are growing their own biostimulants.
Growers using humates, active composts, kelps, and various home made teas and tonics are essentially applying biostimulants. Integrated permaculture and regenerative methods such as those taught through Work in Beauty, or integrated with indigenous practices like those modeled at Covenant Pathways may already be introducing enough natural biostimulants to maximize plant production. If you are willing to learn how to make your own, local materials may be the best source of biostimulants.
But for the average, time- and labor- limited grower, a commercial biostimulant may hold the ticket to successful growth. And for a commercial farmer, a prepared biostimulant may be easier to document and validate for certification purposes. If you decide to go with a commercial product, there are many to choose from. This leads to the next question…
What Biostimulant Should I Use?
There are simply too many variables acting at each site to make on-size-fits-all recommendations. This leaves the consumer two options. You can contact a consultant who will visit your site and work with you to improve your plant production, or you can figure it out yourself by setting up low cost experiments at home. Simply choose what seems to be a good biostimulant, and start using it on a small growing area.
Rapid Indicators of Biostimulant Effects
If you want results for the coming season, there are three tests you can run at home that will quickly reveal whether a biostimulant is boosting the growth of your system.
Simple tests you can do affordably at home include:
- take leaf Brix readings before and 24-48 hours after applying foliar biostimulants. A general rule of thumb is that plants with leaf Brix above 8 are doing real good. Plants with leaf Brix of 12 are prospering.
- run seed germination trials with your regular water and fertilizer, and with added biostimulant. If a seed sprouts and develops more quickly in the presence of a biostimulant, it is likely having a positive effect. Most seeds germinate within a week of planting, so your results will come quickly.
- test whole plant growth either on a small section of the property to be treated, or in containers. Container garden experiments can run an entire growing season. These will take more time and planning to set up, but they will allow you to observe more details about how your plant is responding. You can include germination rates and Brix readings as part of your experiment.
- Containers allow testing to occur without making permanent changes to your growing area.
- It is important to run your tests under growing conditions that are similar to where your plants will be growing.
Running an Experiment Sounds Like Work, Is it Worth It?
This depends. If you are gardening for something to do, maybe not. If you are growing for profit, or growing to produce food that nourishes you and your family, you are going to be growing for a long time. Taking time today to learn secrets that will make production easy for years to come can be really worthwhile.
Every time I set up an experiment, I complain to myself about the extra work it takes to treat both controls and experimental treatments. Careful documentation is the most time consuming component, and the first one to get skipped when other demands call. But always, I learn things from experiments that change the way I approach gardening.
Recently, I tested two commercial biostimulants. One product is the Bloomin Minerals product available through the Youngevity network I buy my vitamins from. The other product was developed for commercial growers. It contains minerals and humates comparable to those in Bloomin Minerals, but it also contains a carefully selected blend of living microbes, kelp extracts, protein hydrolysates, and other good stuff. I honestly expected that the new product may outperform the Bloomin Minerals, simply because it had both the nutritional and the living components plants need. I also expected that all plants would grow well, and observed differences would be small. The surprising results are discussed in Biostimulants Can Reduce Damage Caused By Salt Stress.