Earlier this week I spotted a stand of giant ragweed growing next to a parking lot. That brought back memories from long ago when I had a small farm and was growing corn and soybeans. Back then there were a lot of those types of small farms around.
I was a young guy and was excited about my first crop of field corn. It was only 40 acres worth of corn, quite small even back then. I took the first truck load to the local grain elevator. The owner took one look at it and said he would not buy my corn. He told me it was contaminated with a small amount of giant ragweed seeds. He said he had only seen them once before in his entire career — lucky me.
The problem with giant ragweed seed is that although it is shaped differently, it is about the same size and weight as a kernel of corn. The seed cleaning equipment at that time could not remove ragweed seed from corn.
Nowadays, giant ragweed is all over the place. You can spot it in fields and in ditches along the roadways and competing with farm crops like corn and soybeans. It’s become a major problem on many farms.
Not only is it a major weed on farms but in certain areas, it is also a major contributor to the amount of ragweed pollen in the air. A single plant can produce ten million pollen grains a day or about one billion during its lifetime. Compare that to a another plant which produces large amounts of pollen, the corn plant which sheds two to twenty-five million pollen grains its entire life.
Giant ragweed is not as common as its cousin the common ragweed. Because the population of common ragweed is much higher than giant ragweed, most of the pollen in the air is of the common ragweed variety.
Giant ragweed is native to north america. It usually doesn’t show up in an area unless the soil has been disturbed for some reason, like tilling a field, or in this case, building a parking lot.
Fortunately, the grain dealer eventually took pity on me and bought my grain. Regulations allow a shipment of corn to contain a tiny percentage of weed seeds, not enough make a difference in the final product. So much corn was coming in during that harvest season that when my minuscule crop was mixed in to the rest, it virtually disappeared into the tons and tons of corn from other farms.
I came across an old publication about dealing with weeds in farm and garden situations. The author discussed why weeds grow where they do and how we can use that knowledge to reduce weeds naturally without the use of herbicides. Needless to say, that is a large and complex topic, too big to go into detail here.
One item that did jump out at me was a unique way of killing field bindweed.
Field bindweed is one of the most tenacious weeds we have in the garden. If you have ever had a bindweed infestation in your garden, you know what I’m talking about. It grows from a net work of underground roots that will grow several feet deep and have a lifetime of twenty years or more. I’ve blogged about this weed in the past.
Other than using chemical herbicides, the traditional way of controlling bindweed is to starve the root system by cutting back the tops whenever you see them. That may mean as often as every few days or so, especially early in the season. By cutting back the tops, you remove the leaves stopping all photosynthesis. That forces the plant to use stored energy as it sends up new shoots. Eventually, the plant runs out of energy and dies. That process may take a few years.
The author of the weed publication offers a different take on bindweed. He mentions, almost in passing, that dahlia roots secrete a substance that kills field bindweed. I’ve been trying to think back to all of the hundreds or even thousands of dahlias I’ve grown in the past and can’t seem to recall ever seeing bindweed growing with dahlias. I’m not growing dahlias this year and have not grown them for several years.
If the dahlia vs bindweed theory is true, that gives gardeners a new ally against this noxious weed. It would mean taking a piece of ground out of normal production and growing dahlias there for a season, which would not be all that bad of a thing I suppose.
Growing enough dahlias to cover a large area presents a whole new set of challenges. That is a topic for another time.
We had to get our bird netting on the grape vines this week.
The grapes have been turning purple very quickly and are getting sweeter by the day. That whole process of ripening is known as veraison in the wine making world. But for me and the neighborhood birds, it’s just plain ripening.
The birds are starting to sample the grapes and I can tell more fruit was missing every day. They are not eating a lot of grapes just yet. Even though the grapes are becoming a deep purple color they are still not sweet enough. Birds start eating grapes when the sugar content reaches about 15%. Grapes need to be around 22% in order to make wine. A little simple math tells us the grapes will be long gone before they ever get sweet enough to make wine or even grape jelly for that matter.
Really, the only way to keep birds from decimating a grape crop is to install a barrier so they can’t reach the fruit. That’s where the netting comes in. This year we invested in new, premium polypropylene bird netting. The netting is 14 feet wide and 45 feet long — two panels will cover the row.
We unroll, then drape the net over the vines. Then we fold the bottom edges up and fasten it back on itself to enclose the entire grapevine.
Once we get the vines covered and they are protected from the birds, we’ll be able to taste test the grapes at our leisure and pick them once they have sweetened up to our liking.