The planting is 99% complete and now all we have to do is take care of everything. Weeds are an ever present challenge as you well know. Today I will address one common weed and its life cycle and how to avoid getting the weed along with some of the controls used battling it.
Tracking soil or mud from one field to another is a sure fire way of getting new and unwanted weed seed into your garden or field. Be vigilant about keeping equipment clean between fields. If you have your garden tilled for you, make sure the tiller gets a thorough cleaning and washing before it sets down on your garden. Make certain there’s no dirt or mud on the equipment prior to tilling. This may come across as excessive, especially if you till gardens in your spare time, but believe me when I say it’s worth it. Same advice goes with your hand tools and your shoes. I’ve brought galinsoga into my garden and greenhouse by way of my shoes.
I know about moving weed seed from personal, as well as professional, experience. We bought a piece of land several years back which hadn’t been planted in at least 40 years. I thought we would have few if any weeds and, after battling weeds here at Johnny’s so long, would be happy to have a plot without them. My well meaning but unknowing neighbor tilled the garden with a tiller used in a conventional corn field. You could tell by the weed germination pattern exactly where it was tilled. The plant population of lambsquarters, redroot pigweed and velvet leaf was easily noticed. I had seen none of these weeds previously and now have my hands full.
Galinsoga is clearly the worst weed we have. If you don’t have it, don’t get it at all costs.
I quote Weeds of the Northeast “Hairy Galinsoga is one of the most difficult to control weeds of vegetable crops”. Be vigilant in your efforts to not get it. Years ago we didn’t have it here on the farm. One year it appeared in field 11 and the rest is history. It now has spread to every field on the farm and most of our isolated fields.
First the bad news: Galinsoga has small yellow blossoms which hold seed that is mature once the blossom opens. That seed has no apparent dormancy so as soon as it blossoms, it can germinate creating generation after generation rapidly. Several generations per year are common. The plants have a large root system so when pulled out and left on the soil surface, they will often reroot. Each plant is capable of producing up to 7500 seeds so you can see the importance of getting all the plants in blooms out of the field.
Now the good news: Galinsoga seed is short lived. Estimated time of viability is two years in the soil. If you have a plot you can take out of production for a couple of years, you can get some control of this weed. Killing Galinsoga is also relatively easy. If cultivated when small it is easiest to kill. It also is susceptible to flaming and kills easily with organic herbicides. Galinsoga is frost sensitive so will turn black and mushy with the first frost. Timing is crucial in controlling this weed; if you are expecting a frost at a certain time, you can let it grow until then and hopefully you’ll get that frost; if you don’t you’ll have to use some kind of control lest it get out of hand.
Until next week, Brian
For more information on Hairy Galinsoga, as well as some pictures, Virginia Tech's weed identification guide website is a good resource.