By Penny Pawl, U.C. Master Gardener of Napa County

Some time ago I wrote a column about African keyhole gardens. These innovative gardens are circular and have a place in the middle for worm composting bin. The design has performed so well that you can now buy a wooden kit for such a garden.

Last winter, I had an invasion of gophers who were eating my produce before I could. All my raised beds needed to be emptied and new wire put in the bottom.

I had been thinking about adopting the keyhole garden method of composting. Here was the opportunity to put my plan into effect.

My helper and I cut the bottoms off of two garbage cans so the worms could move back and forth. Then we drilled holes all along the sides. These garbage cans were placed in the bottom of the beds right on top of the gopher wire. Then we surrounded them with soil, keeping the rims of the cans above the soil, and put the lids on.

Next I had to supply the bedding for the precious red wiggler worms I planned to add to the cans. Red wigglers are used in composting because they are the only worms that eat decomposing materials such as kitchen scraps, coffee grounds and plant waste. Any seeds that end up in the compost—such as seeds from watermelons or tomatoes—may reseed in the bin or when you spread the compost around, so be careful what you put in the bins. I once had a compost bin full of maple seedlings because I had added maple leaves.

The idea behind this type of composting is that the worms will move in and out of the cans and, as they do, will take some of the compost with them. By this method, the compost gets spread around and helps the plants thrive. Worm compost is a balanced fertilizer and helps improve the texture of your soil.

I fill the bins with plain cardboard, which the worms love, as well as newspaper, kitchen scraps and soft trimmings from plants. On top of the bedding, I put large black plastic bags to keep the bedding moist. Something good is happening in there.

I have noticed that these cans seem to dry out faster than my regular compost bins. Maybe moisture leaches out of the bins into the soil. I check the bins often and water once a week with a garden hose. I also noticed that these bins were warmer in winter than my free-standing bins, which is good for the composting process. The soil around the bin must be keeping it warmer.

Online I found red wigglers from Africa. They are bigger and longer and eat more. I put them in one bin only so I could check on how they do.

I don't know if I will need to clean these bins out like I do with the free-standing ones. In spring, I plan to take out all of the uncomposted material and see what the bottom of the bin looks like. That's where the compost it.

Since I created these bins, they have attracted other creatures such as snails and slugs. And greeting me when I check the bins are some small toads that catch all the fruit flies. One bin has six tiny toads in it. I have also seen two alligator lizards and a black racer snake.  

Workshop: U. C. Master Gardeners of Napa County will hold a workshop on “Garden Basics IV – Landscape Thoughts” November 3. There will be a discussion of firewise and hillside landscaping; rain gardens and swales; different mulches and permeable hardscapes as well as possible solutions to problem landscaping areas.Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment).

Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.

Penny Pawl, U. C. Master Gardener of Napa County

Worms are not native to North America. About 20,000 years ago, our continent experienced an Ice Age, along with Europe and Asia. The phenomenon decimated the worm population, with the only survivors in parts of Turkey and the Mediterranean.

Over time, as Eurasians and Europeans began migrating to new lands, they brought plants for their new homes with them. Worms and other critters hitched a ride. On the East Coast of the U.S., these worms have changed the ecosystem because they eat the fallen leaves that trees also depend on for nutrition. This phenomenon is changing East Coast woodlands.

As the immigrant settlers moved across the country, so did their worms. In the Western U.S., worms have benefited the land and consequently the crops that people grow.

If you dig in damp soil, you will probably run across at least one worm. These earthworms (Lumbricus terrestris) live in the first 12 inches of soil. Their digestive systems turn soil into ever finer soil, and their castings improve the health of the soil. Worms also turn the soil, creating tunnels for water and roots. They won't thrive in compacted soil.

Night crawlers (Eisenia hortensis) also live in the soil. However, when the air is damp, they come to the surface and feed on plants there. They are much bigger than red wigglers. Once I put two night crawlers in a worm compost bin. When I cleaned the bin the following year, there were still just two night crawlers in the bottom of the bin. These worms had no interest in composting. However, some night crawlers from Europe and Africa will apparently do this work.

Red wigglers (Eisenia fetida, also known as fishing worms or manure worms), are the kings of composting. They are the worms you find under a stone, pot or pile of leaves. They only eat decaying matter.

Once I put a layer of maple leaves in one of my bins. I seem to have raked up some maple seeds, too, because a week later I had a crop of baby maples in my compost. The worms ate the leaves but not the seeds, which were still fresh enough to sprout.

Red wigglers eat or chew 90 percent of what you give them and that includes newsprint, plain cardboard, egg shells, daffodil leaves, spent flowers, vegetable leftovers, coffee grounds and animal fur. From these materials they produce compost, a mild fertilizer that you had a hand in.

Spread your worm compost over a garden bed, water it in, and the nutrients return to the soil. A lot of gardeners also put a little worm compost in the planting holes for their vegetables for an extra boost. I feed my potted plants with a handful of worm compost.

African red wigglers (Eudrilus eugeniae) grow much longer than our red wigglers and eat more. The two types can survive side by side because they are not necessarily interested in the same decaying material. The African worms need higher temperatures, but I have corresponded with someone in Michigan who is successful raising them in his garage.    

Other critters will move into your bins, too. Sow bugs or pill bugs will be the first to arrive, and their manure is just as good as worm castings. My compost-bin residents have included small toads, earwigs, slugs, snails, an occasional small snake (they like worms), a few lizards, ants and various flies. Most of these creatures coexist but I do get rid of the fruit flies.

This year I am experimenting with putting compost bins in my raised beds, a technique common to African keyhole gardens. I put a compost bin in the middle of each bed so the worms can travel back and forth and hopefully fertilize the bed they are in. Only time will tell whether this experiment is successful, but I will report back.

Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Rose Care” on Saturday, June 2, from 10 a.m. to noon, at University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Roses will grow without any care.  But they will thrive with a little TLC! Master Gardener rose experts will answer your questions regarding rose care at this popular forum. By June, the first spring blooms have faded, and many plants are beginning to show stress. Look for black spot, rust, mildew and aphids. Bring samples of what's plaguing your roses. Online registration (credit card only); Mail-in/Walk-in registration (check only or drop off cash payment)

Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.

I have a manure farm in my backyard. Before you decide to move on to another article, you should know that my farm is small, only about two square feet in size. It consists of a plastic bin in which live hundreds of small, red worms. Known as "red wigglers", they are different from the earthworms you find in your garden. These little wonders will eat your food waste and create nutrient-rich manure that you can use in your garden. 

My worms live very comfortably in their little storage bin, nestled in a bedding of shredded newspaper. Every now and then I take some leftover vegetables and place them under the bedding. Before long, the little red wigglers are all over it, chewing it up and turning it into the garden version of "black gold."

Their manure, or castings, looks much like soil at first glance. It is, however, around five times more nutrient rich then regular soil. The worms are good at their job of consuming and excreting up to half of their body weight in organic matter each day. This leaves me in awe. What if I could attempt such a feat?

Getting started on worm composting, also known as vermiculture, is easy. Obtain a wood or plastic container roughly one foot deep. Drill ¼-inch holes on the sides and bottom to allow air and moisture to pass in and out of the container.

Fill the bin with 1-inch thick strips of damp, but not wet, newspaper. This bedding will help your worms stay cool and damp, as well as give them an additional food source. Glossy newspaper inserts or magazines won't work as bedding. Choose a location that is not too cold or hot. I keep my bin in a shady corner of my patio, but many people keep theirs inside in the basement or laundry room. 

Now that you have built your worm home, you can add worms and begin feeding them table scraps. Don't overwhelm them with too much food at first. Watch to see how quickly they eat what you give them, and raise the amount as the population grows. They reproduce rapidly, so you won't have long to wait.

Your new friends will be happy to have any leftover vegetables, fruit, dead flowers, tea bags, coffee grounds and even egg shells. They are vegetarian, however, so don't feed them any meat or dairy products. It is also best to minimize acidic foods such as citrus.

If all goes well, in a few months you will start to see worm castings accumulating at the bottom of the bin. There are many ways to harvest them, but I find the following method to be the easiest. First, remove the finished compost and set it aside. After adding fresh bedding, place hardware cloth across the top of the bin. Put the finished compost on the hardware cloth and let the sun or another bright light shine onto it. The worms will move away from the light, through the compost, and out the bottom into the new bedding. Afterward, pick through the compost to find any stragglers that you can transfer by hand.

Now you have a highly nutritious, homemade fertilizer. You can use it wet, but to store it for later use, let it dry. Just sprinkle it in your garden before watering to enrich your soil. I also like to put a handful in the bottom of a planting hole to give the new plant a healthy start in my garden.

Red wigglers can be found at many fishing supply stores and online. You can also get some worms and a free bin if you attend a Master Gardener worm-composting workshop (https://compost.naparecycles.org/). The workshop is also your chance to get more detailed information on vermiculture. I started my bin after attending such a workshop, and now can't imagine how I ever gardened without it.

Workshop: U. C. Master Gardeners of Napa County will host a workshop on “Landscape Trees, Shrubs and Maples” on Saturday, June 10, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. The workshop continues from noon to 2 p.m. with a field trip to a local garden. Trees and shrubs add pleasure and value to your garden. Discover an array of options for the home garden and how to add structure and interest with landscape trees and shrubs. Tips for selecting, planting, and caring for trees and shrubs will be discussed. Please bring a sack lunch, dress for outdoor conditions and wear good walking shoes. Online registration (credit card only)
Mail-in registration (check only or drop off cash payment).

Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.

 My worm hobby began in 1999 after I attended a Master Gardener composting class. This hobby continues to fascinate me. Worms recycle my kitchen garbage, and I'm still amazed by the process.

    Two years ago I went to North Carolina State University's annual vermiculture conference. The conference was so inspiring that I went again last year. It is the only conference about earthworm farming and mid- to large-scale vermicomposting in North America.

     The conference, coordinated by a university extension specialist, offers science-based information. One of the topics was the difference between vermicompost tea and leachate.

     Both begin with red wigglers, which are small earthworms that live near the top of the soil and consume organic matter. I feed my worms kitchen garbage and disease-free plant debris from my yard. My goal is to create vermicompost and aerated compost tea for nourishing a healthy, chemical-free garden.

     To make aerated compost tea, you need a 12- to 24-hour aeration cycle, de-cholorinated water and finished compost. Alternatively, you can make the tea in a bucket in three to seven days by stirring occasionally.

     By introducing air, you encourage the proliferation of aerobic microorganisms and discourage the anaerobic microorganisms that may produce byproducts unfavorable to plant growth.

     Vermicompost tea contains a large diversity of bacteria, fungi, protozoa and nematodes. These microorganisms increase soil biological activity, encourage plant vigor, yield, bud break, fruiting, flowering, color, root volume, seed germination, and pest and disease resistance. You can use vermicompost as a foliar spray or soil drench.

     Many worm composters are unfamiliar with the topic of aerated compost tea, preferring to use the leachate that many vermicompost systems encourage. Although leachate seems to benefit plants, it comes with some risk.    

Research suggests that the use of leachate should be discouraged. Vermicompost is not leachate. The excess water that drips through a worm bin is leachate. It picks up undigested material which may contain pathogens and chemicals toxic to plants and humans.

A properly maintained worm bin will not collect or seep excess water or leachate.

Use leachate to water a favorite weed, or flush leachate down the toilet. Using leachate on plants, especially edibles, is not worth the risk of pathogenic contamination.

     As for the vermicompost produced by red wigglers in the worm bin, the worms and microbes gobble up the pathogens in their environment and do not release the pathogens back into the soil.

     Microbes are part of a worm-bin ecosystem. They live and work amongst the worms in the vermicompost, eating and overpopulating the pathogens while being ingested by the worms.

     The vermicompost is ready to use when you don't recognize the original feed stock. It should smell clean and earthy and appear brown and crumbly.

     I wondered if the pathogens the worms previously digested are freed upon their death. Otto D. Simmons III, a professor of biological and agricultural engineering at North Carolina State University, says that “live worms digest the dead ones and the pathogens are eaten by the surviving worms.”

     So why use aerated compost tea? Because it adds organic life to the soil, improves soil structure, water retention, root depth and growth.

      A foliar spray of vermicompost tea protects plants from pests and diseases, thus reducing the need for chemicals. I love the idea that my plants seem happier and stronger due to my kitchen waste.

     Be sure to use non-chlorinated water when making tea or watering your worm bins. City dwellers can set a jug or bucket of water out for 24 hours to de-gas the chlorine. Rain water collected in buckets is a good alternative.

Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. Napa County Master Gardeners (http://napamg.ucanr.edu) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4221, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions?