Barreca Vineyards

Barreca Vineyards

From Vine to Wine since 1986

A Caste of Worms

In Robert Heinlein’s book, Dune, giant sandworms produce a drug called “melange” (known colloquially as “the spice”), which is highly prized across the universe for its medicinal and mystical properties.  (wikipedia.org)  Although wildly fictional, some truths linger in that account.  Melange is created when excretions of the sandworms’ larvae react with water and sunlight. At this point the tale gets a bit, shall we say, “messy”.  In the real world, worm excretions, castings, are an indication of healthy soil and contribute to it.  Can they eat sand? How big do they get?  What is really going on down there?

These persistent questions kept making me think of someone one of my grape plant customers mentioned, “Marvin the Worm Guy” in Spokane.  So I Googled it.  Well the closest thing is Marle Worm Growers in Otis Orchards.  As it turns out, the worm guy is Jeff Wood, who runs Marle Worm Growers, and indeed knows a lot about worms.  I finally got a chance to meet him in person and we talked and walked around his place for a couple of hours.  It could have been much longer.  Jeff does educational presentations for Spokane Community College, Master Composters and Master Gardeners.  He looks at worms as not just a commodity he grows and sells, but as a highly valuable component of healthy soil. Building healthy soil is his passion.

Jeff Wood

Jeff called microbes “engines of the soil”.  Carrying that analogy a little further, worms are trains full of microbes spreading them everywhere they go.  Worm castings are not just good plant food, they are highly refined and PH-balanced food that has some surprising qualities.  Seeds drenched in tea from worm castings produce long healthy roots even before emerging from the ground. In a recent episode of the Regenerative Agriculture Podcast, Nicole Masters describes this effect as the highest yield per cost of any enriching application you can do to a crop, costing mere pennies per acre.

It is not surprising then that Jeff makes several kinds of compost tea and says that using compost tea on your plants is a technique that everyone can afford and is tremendously beneficial.  He has a large tea brewer that preheats water, introduces air and grows microbes essentially overnight. So yes, he sells compost tea as well as a huge inventory of other products, besides worms, that are good for the soil.  He also sells soil itself to landscapers, gardeners, greenhouses and farmers.  He points out that crucial consideration are how much time you have and the nutritional needs of plants which change through the course of a season.

Foliar applications of tea enhance growth and can also control insects.  They last 3 to 5 days and need to be modified and applied frequently.  A root drench tea will last 7 to 10 days.  Worm castings added to the soil last a couple of weeks and granular fertilizers, which Jeff also sells, can last a whole month.  Every step of the way means more cost but more time to work with.

When they are young, plants might need some insect protection, mild nitrogen fertilizer and some soluble seaweed extract for its mix of minerals.  With more growth in the middle of the season, plants can feed on more nitrogen-rich fertilizer like aged manures and of course worm castings as the plants put out green leaves. Toward the end of the season, plants don’t need as much feed but you want them to settle into the winter with organic matter that is composting and retaining moisture.

Through all of this, worms have their cycles too.  Being so closely aligned with composting, worms like what compost likes: temperatures from 55° to 77°.  Temperatures above 90° will kill them. At temperatures under 55° they are not very active.  I asked about compost piles that can get to 160° F.  Jeff told me that the worms will move away from the hot compost, usually to the bottom of the pile.  When the compost is cooler but still gooey, they come back to eat.

Worms don’t have teeth.  Like chickens, they grind up their food in a gizzard.  So a little dirt or light sand can help break down the rotten vegetables and fruit (as long as it is not acidic like citrus) that is their main diet.  If you are growing them in a worm bin, it is harder for them to get away from hot compost, so Jeff just adds a little vegetable matter in spots near the top of the bin.  It takes 3 to 4 days for worms to eat a feeding.  They eat their weight in food every day.  If it takes longer, you may be feeding them too much.  They like a combination of green (vegetables, grass and leaves) and brown food (wet bedding and rotten fruit) , with an emphasis on the green.

Marle Worm Growers sells a variety of worm growing equipment.  A common thread is that worms move on to new food when the old is exhausted.  So some systems have you add another box of bedding and food on top of the old, the worms move into the new food after a few days and you can remove the old box to get the castings. Similarly, some systems have two sides with a screen between them.  Feed on one side and the worms move there.  You can encourage the move by letting light shine on the old side and exposing it to a breeze. Worms hate that. Remove the castings from the first side and it is ready for new food.  Keep in mind that the bedding, which can be shredded black and white newspaper, cardboard, peat moss or decomposing leaves in any combination is also consumed.  Keep it as wet as a damp sponge but not too wet.  Worms need air as do compost and roots.

This does sound a little complicated and there is even more equipment in Jeff’s operation to separate worms, castings and unused material.  For small scale growers Jeff is a big proponent of systems that integrate the worms with growing plants.  The most straight forward is a “worm tube”, basically a 6” or so plastic pipe perforated with ½” holes that the worms can crawl through.  Place it straight down in a raised bed or vegetable garden with a fly-proof screen that you can take off to add ground up kitchen waste.  Don’t add meat or oils, they smell and attract pests. The worms do the work of composting the food waste and transporting it to the roots of the plants for 4 to 5 feet around the tube. 

Taking it one step further, there are “garden towers”.  These are essentially worm tubes in the center of a 4 foot high structure that lets plants poke out the sides and feed off the worm castings carried out of the tube by worms.  Additionally, you can pull the worm castings from the bottom of the tower and put them back in on top of the soil.  This is great for gardening on your patio or porch.

What I have however is a vineyard with sandy soil.  I learned from Jeff that the red wiggler worms are going to avoid the sandy soil. They want several inches of organic material on top of the sand.  They will however bury themselves deep in the ground during the winter to avoid freezing.  Even deeper, 3 to 5 feet, are nightcrawlers.  They also produce castings from compost.  Their deep holes help aerate the soil.  They make great fish bait, but are harder to propagate. 

There is a lot more to worms than meets the eye.  The cast of worm species goes on and on.  I am tuning up my compost pile to feed the red wiggler worms.  I’m also covering it to keep in moisture and encourage worms to get closer to the surface. I noticed after uncovering it once that robins were right there pulling out some worms for themselves.  You might want some worms for yourself. Feed them and they will help feed you.


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