Mustard Seed Meal in the Orchard



Apple orchards along the Washington by-ways

In the past Bill Piexoto used to tell people that he could no longer plant new apple trees in his orchard – until, that is, he found out about mustard seed meal. Orchard soils, in the process of maintaining healthy trees over time, become imbalanced and often cannot support new saplings without special treatment.

Conventional farmers fumigate their orchard soil to ensure a good start for new trees. What we’ve learned in the last decade, thanks to breakthroughs in DNA sequencing and genomic research, is that  fumigation is like chemotherapy – it actually kills all the life in the soil microbiome for the short-term gain of killing a few bad bugs. We are starting to wonder if there’s something wrong with this approach – aren’t we sophisticated enough to update soil care?


Piexoto participating in trials with Farm Fuel staff

Piexoto has managed organic orchards since the 1980’s in Corralitos, Santa Cruz County, California. He knows there is a symbiotic relationship between plant roots and the soil microbiome – each feeding the other. Some older trees provide a diminishing amount of healthful photosynthetic substances (sugars) to exchange with microbes in the soil for water and nutrients. So they become unhealthy and are removed. The microbes left behind in the soil that were dependent on those old tree roots are ready to devour a young sapling, sucking the life out of its roots before it has a chance to develop.

Replant.Disease.Peach.2     Trunk.Replant.Disease.2

Typical symptoms of replant disease

What is a farmer to do if he or she farms organically? According to Piexoto, there was no point in replanting into the same soil. And in order to maintain his orchard as certified organic, he is prohibited from chemical fumigation. Finding mustard seed meal was a welcome discovery.

When applied at the optimal rate of about 1-3 tons per acre (yes there is math involved*), crushed mustard seed meal, derived at Farm Fuel from a proprietary blend of pressed mustard seeds with the oil removed, revitalizes and rebalances the soil, when mixed with water, due to an explosion of isothiocyanates.

Just like the heat you feel on your tongue when you dip a bite of sushi into wasabi (which is derived from the horse radish root, another brassica), the soil in the orchard row gets a flush of mustard heat when first irrigated.

This flush peaks after about 12 hours, according to research, and then over two week’s time, the mustard meal turns into a healthy vegetable-based organic food for the kinds of microbes that rebalance your orchard soil.

For those in regions where dry and depleted hilltops are being replanted with organic orchards and vineyards, mustard seed meal can kick-start the soil to a high level of productivity in combination with compost blended with trace minerals and perhaps mycorrhizal fungi. Many of Farm Fuel’s customers make interesting blends, including Jeff Chasser at The Soil Makers ( and Maine Potato Lady Alison LaCourse. And Cynthia Sandberg of Love Apple Farms regularly recommends mustard seed meal as an essential ingredient in her double-digging soil building recipe.


Dave Benner of Adams County, PA, giving a tour of some of the orchards where he uses Mustard Seed Meal

For those wishing to replace chemical fumigation in conventional systems (like Dave Benner in Adams County, Pennsylvania, pictured), mustard seed meal, when applied and cultivated deeply two weeks to six months in advance of planting, can awaken a healthy microbial community in the orchard. As a farmer, instead of going to war with bugs and pathogens, you’re building the soil’s immune system.

It’s a different approach to farming – working with nature rather than fighting against threats – to produce a healthy bottom line. As Reuben Stolzfus, of Lancaster Ag Products, says: “I don’t want to kill things. Our passion is agriculture and promoting healthy living through farming and gardening. Our great desire is to use our company to  touch individual people at the heart level, help families to better health, and challenge all of us to leave a greener tomorrow than what was given to us.”

Nature has something to exchange with us – healthy plants and foods for our table when we feed the soil its own balanced feast.

A thriving farm system is almost a closed-loop system except that the plant materials we harvest as fruits and vegetables take some nutrients with them out of the loop. If eaters buy from farmers who are paying attention to their soil, their produce will contain the trace minerals and nutrients we need to thrive. Replacing this nutrition year after year in an orchard is an art and a practice that can be learned and applied to new plantings.

Maintaining orchard soils after the initial planting can include cover cropping between rows, which provides a diversity of foods to the soil microbes, depending on which cover crop cocktails you choose to serve. As Cover Crop Coach Steve Groff says “Just like you need to choose your own spouse, you need to choose your own cover crop blend. People may give you suggestions, but it’s up to you.”

Great places to look for cover crop blend suggestions include the Lancaster Ag Products catalog, Penn State’s cover crop research results website, and their newsletter. You can also talk with Steve Groff, the Cover Crop Coach. Find him on his website:

Not common in California until recent drought years pushed farmers to retain soil moisture, cover cropping has multiple benefits: it can shade out weeds, attract beneficial insects, keep soil loose, prevent erosion, and partner with microbes and worms in the formation of healthy soil aggregates which help soils retain moisture more effectively. It also has the added benefit of sequestering carbon in the soil. The deeper your soil organic matter, the more carbon you are sequestering.

Side dressing with mustard seed meal over the years, especially just before rain, gives mature trees an invigorating jolt of isothiocyanates for rebalancing. But it is really not necessary to till and disturb healthy microbial communities between tree rows, as long as you keep them fed with cover crop root exudates, mulched to retain moisture, and you observe carefully what’s going on with the leaves, blossoms, and bark of your trees.


*This comes out to 1 lb per 7.26 sq feet at the 3-ton per acre rate. You can figure the orchard rows are about one-third of the acreage, depending on your set-up.

2 Responses to “Mustard Seed Meal in the Orchard”

  1. Tim Woods says:


    I have a fifty pound bag of Pescadero gold that i use in my raised vegetable beds.

    Can I apply PG now, 2/17, to my various fruit trees. If yes, what quantity would you suggest?

    Best, TW

  2. EllenFarmer says:

    Depends on the age of your trees.
    For a tree less than 1 year old, use a light application and incorporate a few inches into the ground, then irrigate or let rain soak the mustard seed meal into the soil. For older trees, you can apply up to a ton per acre, or around a half pound around a well-established tree. If you are applying mustard seed meal to an entire established orchard as a side dressing, divide the one-ton per acre rate by the number of tree rows.

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