June 2013 Issue 2
In this issue:
1) Botany in the News: Plants Discovered Chatting On Their Own Internet!
2) Gardening Tip: Dealing with Gophers, Voles, and Mice in the Vegetable Garden
Botany in the News:
Plants Discovered Chatting On Their Own Internet!
Turns out that plants are talking to each other. Okay, not as in “Hey neighbor, grown into any good bits of compost lately?”, but they do have ways of telling each other bits of important information.
Most plant species (95% of those studied so far) develop a symbiotic relationship with mycorrhizal fungi, which connect plants together underground. (The slimy photo above is of a plant root connected to this mycorrhizal net.) The plant makes sugars that it feeds to the fungus, and the fungus gathers minerals from a wide area and feeds them to the plant roots. But there’s more...
What Chinese researchers discovered recently is that plants use these mycorrhizal networks to send messages to each other! When one plant is attacked by a plant disease, it sends a chemical signal over the network to alert nearby plants, which then start to produce chemical defenses against the specific disease.
We silly humans tend to think of soil as just a substrate that gives plants a place to anchor their roots, and that any old substrate will work as long as we add fertilizer. While it is possible to grow plants that way (as in hydroponics), when we do we have completely bypassed the intricate natural mechanisms that have evolved over millions of years to support life on planet earth by recycling nutrients. The more I learn about soil and the almost infinitely complex living web of life that exists there, the more I love, trust and appreciate nature’s wisdom in the way “she” provides health-giving food to all of earth’s creatures.
Application to Raised Beds
In framed raised-bed gardening, we use potting soil, which is a lifeless mix. It is designed to provide a root substrate with pore spaces for air and water penetration, but it does not have a thriving natural soil ecosystem of earthworms, springtails, good bacteria, actinomycetes, fungi or mycorrhizae.
Since there is a lot more going on in the plant world than meets the eye, I wonder whether the plants in these situations get lonely for their natural ecosystem. Do they miss their fungi and bacteria friends? Do they miss chatting with their neighbors on the mycorrhizal net? But most importantly for us, are they as deeply nutritious and vibrant as if they were grown in rich, living, natural-ecosystem soil?
I tend to trust nature the way God designed it, which is one of the reasons I garden in the first place.
So if you are a raised-bed vegetable gardener, I recommend setting your raised beds directly on the earth, with no barrier between the ground and the potting mix in the bed. Over the years, as you add lots of homemade compost (which is rich in carbon and nitrogen materials, lignins, humus and microorganisms), you will eventually develop a natural soil ecosystem in your raised beds. Earthworms and other macrofauna will come up into the bed, and your vegetables will be as healthy, disease-resistant and nutritious as possible.
This entry came in response to a reader’s question (thank you Maria!): “How can I keep gophers out of my garden, without trapping or poisoning them?” Gophers, voles, prairie dogs, moles and even mice can cause a lot of damage to a vegetable garden. One day everything’s fine, and the next day plants are drooped over and dying because their roots have been eaten out from underneath them.
Controlling Gophers in the Vegetable Garden
This is a tough one, because the garden is so inviting, like a smorgasbord for burrowing critters. There are a few things you can do organically to deter them, but it takes a consistent effort to deter them enough to avoid any loss of produce.
Dog and Cat Poop
Gophers don't like fresh dog or cat poop put down their holes. These poops won't actually hurt anything in the garden, but it's possible that they could carry parasitic worms, so just make sure to wash carrots or other root vegetables extra well after harvest. But here's the weak part of the plan: gophers will at first just dig more holes. This is why you have to keep up with it, but eventually the gophers will move out. (And here's a good one for you: I read a long time ago in Organic Gardening Magazine that lion poop is very effective! So if you can, just go up in the mountains and rustle up a little cougar poop, you'll be all set! )
Hot Pepper Cotton Balls
Gophers also don't like really extreme hot pepper. Try to find extra hot powdered cayenne (try Whole Foods or a Thai or Mexican specialty shop). The best is to grow or buy habañeros, dry them and powder them yourself. But habañeros need more dry heat than other peppers to quickly before they rot. Whiz the dried peppers in a blender to powder them, but do it outside and wear a mask and gloves. Seriously, this will make you cough and will burn your hands if you're not careful. Buy a bottle of castor oil (available at Whole Foods or some drug stores), which is very thick and viscous compared to other vegetable oils, and pour two cups in a jar. Mix in a quarter cup of dried cayenne or habañero, and then soak cotton balls with it and stuff it down the gopher holes. Again, you'll have to keep up with it, stuffing new holes as they appear.
Cages or Buried Fence
Make cages out of chicken wire, dig big holes and bury them in the garden, and then plant your garden plants in them. Make sure they stick up above ground far enough to keep the gophers from going over the top. If you’re building raised beds, staple chicken wire or "hardware cloth" (which is 1/2" mesh wire) on the bottom of the raised bed as it is installed it to keep out burrowing rodents. A more radical (and expensive) choice would be to hire a Ditch Witch to dig a deep trench all the way around your garden plot, and then to build a fence all around the garden that has galvanized hardward cloth buried around the perimeter. If you have a serious problem, this might be worth it. (When I lived in Montana, my neighbor up the canyon had to build a 12-foot high fence all around his garden to keep the elk out, so I guess you gotta do what you gotta do!)
Eating gophers is these guys’ job. They can be very effective, but also, I'm afraid, pretty expensive. Gopher snakes aren't poisonous, are gentle around people, and one snake can clear out a garden area fairly quickly. You can buy them on the internet.
deep root seed starting trays