Saturday, September 29, 2012

Plant Health Management

I went to a workshop about organic farming/gardening down at Fort Valley State University this past week. Most of the speakers addressed the administrative end of things - how to get a farm certified as being organic, who needs to get certified, who qualifies for financial help and where to get that help. That was all great information, but that wasn't all we heard about.

Dr. Elizabeth Little, a plant pathologist with UGA, was also there, and her talk was very different. She said some things I've been trying to tell people for years, but she said it all better and with the authority of a PhD who has been doing actual, official research into the topic. The gist of it was this:
There are no organic products that REALLY work for disease management; switching to organic farming or gardening isn't about simple substitutions of one chemical for another. Essentially, in organic operations, it's all about prevention.

The organic farmer/gardener takes a systems approach to plant health - based on fertility, plant selection, crop rotation, sanitation, and site selection. The organic system also relies a lot on biological interference with disease; by promoting a good ecological system in the soil (a wide range of fungi, bacteria, and creepy-crawlies), the organic gardener/farmer heads off many potential problems.

Any problems that crop up typically indicate an underlying health issue.
She emphasized that healthy plants resist disease, and that we can promote good root growth and beneficial microflora (and by doing so improve plant health) through providing compost and other organic amendments, by mulching, by reducing the amount of tillage, and by using cover crops.

Encouraging predator insects, parasitoids, and microbes as allies was also brought up. Relying on an ecological approach of planting flowers that are attractive to these beneficial organisms was part of the biological approach of disease prevention. Some diseases are in the wind and can't really be intercepted or diverted, but others are spread through the feeding of insects, kind of like the way mosquitoes spread disease from one animal to another. The "beneficials" help by attacking the disease-spreading insects.

When I spoke with Dr. Little later in the day, when we were touring the campus farm, she emphasized the "right plant in the right place" approach to plant health in a great example: She said that she had seen lone tomato plants out in the full sun, with good mulch around them, well-fertilized and mulched, and they were completely unblemished - no signs of disease anywhere - when other tomato plants in the area were definitely ailing.

It was great that she chose Tomato as her example, because that seems to be the garden vegetable that is most affected by disease, in a way that causes the most distress to the gardener, in Georgia. Usually, when someone asks me about disease in the garden, we end up talking about tomatoes.

I left the workshop feeling extra-motivated to keep emphasizing the importance of all the little steps - using compost, paying attention to plant varieties and their disease resistance, making sure there is adequate sunlight for the plant, and using mulches and cover crops.

All in all, it was a great day.


  1. Love Dr. Little's point..

    "There are no organic products that REALLY work for disease management; switching to organic farming or gardening isn't about simple substitutions of one chemical for another. Essentially, in organic operations, it's all about prevention."

    That is interesting. Organic farming then goes hand in hand with living healthy lifestyle. Preventative care (vitamins, water, exercise) while more difficult in the beginning is better for the long term.

    Looking forward to reading more of your stuff, just found you via Google.

    PS I still haven't raised tomatoes without squirrel pirates or bugs eating them before I do.

  2. Well, there certainly are parallels between the methods of organic farming and of improving human health, and it isn't a huge surprise, considering that we are both (plants and us) living.

    I think that the "more difficult in the beginning" part of organic gardening is why organic certification for farms usually takes so long, and also is reflected in John Jeavons' ideas (Ecology Action research group and author of "How to grow more fruits, vegetables...") that building soil fertility and health are long-term projects.

    His book talks about expected harvest weights for beginning vs. advanced gardeners, but I think that really refers to the development of soil fertility. Beginning gardeners are working with soil that has a less-developed ecological system, usually. Building that up can take awhile, especially in the kinds of soils we have.

    My sympathies on the squirrels and bugs. They've been especially bad this year. Part of that reflects the drought - thirsty squirrels are going after the juicy tomatoes. The bugs, I think, are partly a result of the crazy-warm winter that didn't kill any of them off for us.

    Thanks for the note! -Amy

  3. Interesting point. When you make bread, it seems as if the first loaf of the year fails. But the more one makes it the better it turns out. Perhaps it has something to do with the yeast or something in the air...

    One year I even put water out for the squirrels hoping it would help. Nope.

  4. Atlanta Tree Pro,
    For me it's pie crust rather than bread, but I know what you mean. Apparently, I've made a lot of bread in my life because I don't usually end up with an awkward loaf after a big break between bakings - they're pretty much all good. With pie crust, though, I tend to have one or two less-than-great crusts each fall - which at my house is pie season.

    About the small mammals - there seems to be very little most of us can do about them. The best way around them actually tends to be a combination of methods - place water far away from the garden, and spray the crops with a hot-pepper spray, and put out traps or sticky stuff that will be annoying on their little paws... One strategy alone won't be enough to deter them.

    Maybe this time around we'll have an actual winter and more normal rainfall. Those would both help!



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