Weeds in the garden

 

Sorry for the delay in this post, but when the sun is shining and the garden is calling it’s hard to sit in front of a computer. Over the next couple of weeks we’ll be covering basic garden care and we’ll start talking about insects. We’ll also be starting to feature great gardens around the Greater Lansing areas. If you (or someone you know) has a garden you’d like featured send me a message.

Gardening season is off and running, but for many of us gardening is our hobby or side activity. Life, work and other things can quickly fill the time that you’d like to put into your garden. While there are some times of the year that your garden can handle neglect, early in the spring is not one of them.

Weeds

Those tiny seemingly innocuous weeds you see popping up might not seem like they are hurting your transplants and seedlings, but looks can be deceiving. Besides being an eyesore, weeds can cause lasting damage or setbacks to your transplants and seedlings especially if allowed to stay for a couple of weeks. A lot of research has been done on weed management, but in general weeds should be removed as soon as possible and definitely before they have reached the four to six leaf stage. This means that weeds should be pulled before they have four real leaves.  For some vegetables (like leeks) weed control should be started as soon as seven days after transplanting! A study on cabbage, cucumbers and tomatoes found that plots needed to be kept weed free for 3-4 weeks after transplanting or yields were reduced. In snap beans yields were reduced by almost 50% when weeds (emerged at the same time as the beans) were not controlled. Weeds don’t only reduce yields by stealing nutrients and shading out those transplants. Sometimes, they can also be hiding disease-causing organisms.

This lambsquarter has four true leaves and should be pulled.

 

Weeds can also harbor pathogens. Sometimes a plant can be infected with a pathogen, but it won’t show any symptoms. There won’t be any leaf spots, yellowing, rot etc. Depending on what it is, that pathogen can then infect and cause disease (with symptoms) on your vegetables. Did you know that nightshade, horse nettle and jimson weed are in the same family as your tomatoes, eggplants and peppers? And lambsquarter and pigweed are in the same family as beets and swiss chard. Just like you need to rotate crops to reduce disease pressure, you also need to manage weeds, especially those in the same family. A number of diseases are believed to survive on weeds including powdery mildew, downy mildew, and some leafspots and viruses.

These weeds are small now, but can quickly overtake a young bean plant

So make sure to find the time this spring to get out there and remove those weeds before they get to be a real problem! And I’ll be doing the same. 

Some sources on weeds:

http://extension.missouri.edu/p/IPM1023-45

Turson, N. et. al. 2007.  Critical period for weed control in leek (Allium porrum L.) http://hortsci.ashspublications.org/content/42/1/106.full.pdf

Weaver, S. 1984. Critical period of weed competition in three vegetable crops in relation to management practices.  DOI: 10.1111/j.1365-3180.1984.tb00593.x

Groves, R. et al. 1995. Association of Frankliniella-fusca and 3 winter weeds with tomato spotted wilt virus in Louisiana.

Aguyoh, J. and Masiunas J. 2003. Interference of redroot pigweed (Amaranthus retroflexus) with snap beans.