Foliar application of microbial products

by Guest blogger: David Stark
of Holganix, LLC

Listen to his podcast HERE

Why to apply

Of course some microbials, for example Bt products for insect control or others designed to suppress above ground fungal and bacterial pathogens, are specifically meant to be applied as a foliar spray.  But what about the majority of microbial products where the benefit is in the soil? In general, there is no harm in applying these as a foliar application. This is good news since many growers don’t have the equipment to apply soil microbes via injection or subsurface irrigation.  There are a few important considerations however when using microbials as part of a foliar spray. And as always please follow the manufacturer’s label instructions.

How to apply

When spraying soil microbes onto plants the most important practice is to use enough water to wet the microbes into the soil so they wash down to the seed or plant roots.  A good rule of thumb is at least 30 gallons of total liquid applied per acre, with more even better. This is important because UV light from the sun will kill the microbes, so we don’t want them applied with little water so they sit on the surface with no protection.  In addition all microbes need food and water, and soil microbes find these below the surface and ideally along plant roots, so use enough water to put them in close proximity to the roots. Many soil microbes can grow and multiply along the roots, but they’re incapable of movement by themselves so they need to be watered in close to growing roots.  This is particularly important for many bacterial products and fungi including Trichoderma and mycorrhizae.  
For most microbial products mixing the microbes with fertilizer is fine, but many products recommend against mixing with crop protection chemicals.  Also bear in mind many microbial products recommend de-chlorinated water since chlorine is very effective at killing microbes. While any method of spraying is fine, some manufacturers caution against using pumps with excessive pressure or small screens since the shear force may damage some microbes.

When to apply

Generally, the best time during the season to apply microbes is at or close to planting.  Beneficial microbes can help with root establishment, nutrient cycling and may protect roots from disease-causing microbes.  The specific benefits one should expect depends entirely on which microbes are applied. Many microbial products require additional applications through the growing season, some as often as every week.
Foliar applications generally are perfectly acceptable, but are there any actual benefits to foliar application?  Again, this depends entirely on the product being used. Some products contain microbes that colonize on and in the plant and these microbes can suppress foliar and fruit diseases and aid in stress responses.  Microbes naturally fight each other for space and resources, so having the beneficial microbes there first helps exclude incoming pathogens. Some products contain agents like fulvic acid, yucca or seaweed extract, and some bacteria produce biofilms.  All of these agents may help with foliar uptake of nutrients so some microbials can assist with a foliar feeding of fertilizer.

Which to apply

Microbes can do amazing things as part of a soil health, plant health program.  Choosing which microbes to use can be daunting. Bear in mind healthy soil has billions of individuals and thousands of species of bacteria, fungi and protozoa in every teaspoon. This diversity matters; each microbe type and species plays a role in breaking down plant and animal debris, cycling nutrients, protecting plant roots, building soil structure and organic matter.  Choosing a product that keeps the complete beneficial microbiome in balance is important since your plants won’t perform their best in soil that is not balanced. 

My recommendation

Holganix Bio 800+ products are a liquid suspension of over 800 species of beneficial soil bacteria, fungi and protozoa; the most biologically diverse microbial product available.  Bio 800+ also is extremely flexible in how it is applied. In over 15 years of use on dozens of professional and college athletic fields, over 700 golf courses, homes, businesses, orchards and farms across North America, about every method has been used successfully somewhere.  There is no need to worry about using dechlorinated water, and application commonly is made via in-furrow injection, through drip tape, fertigation, boom sprayers, backpack sprayers, hose-end sprayers, tractor-mounted sprayers or even watering cans. Foliar application is encouraged because in addition to hundreds of species of soil microbes, Bio 800+ also contains microbes that will protect leaves and fruit. Additives like fulvic acid, yucca and seaweed extracts also are in the product and aid foliar feeding.  Bio 800+ is best used at planting and for row crops this is the only application needed. For produce crops and berries 1-3 applications after planting (depends on the crop) results in fantastic yields and flavor. Bio 800+ is designed to take the guesswork out of choosing which microbial to use; it is a complete biome in a jug. Please give us a try.

UrbanFarm.org/foliarfeeding

About this author:

Dr. Stark is President of Holganix, LLC where he leads the company’s efforts to expand its business into agriculture. Dr. Stark spent over 25 years with Monsanto Company where he held various senior leadership roles in technology, corporate affairs and business operations.
In 2015 he went to work for Holganix, sells a line of 100% natural bionutritional products for turf, ornamental and agriculture use. The product starts with a proprietary process for making and concentrating a diverse mix of over 800 species of beneficial bacteria, fungi and protozoa. The end result is the most complete mix of Organic beneficial microbes on the market.

How to reach David:        

Website: holganix.com

Email: dstark@holganix.com