For the life of me, I cannot seem to grow weeds lately for my nursery trials. Most growers would love to have my problem but when you are testing new herbicides it helps if there are some weeds coming up in the untreated pots to know whether the new materials have any effect.
At first I blamed it on the potting mix (I changed from bulk to bagged) but now I am thinking it may be due to how I irrigate. And that may be why growers have weed problems. You see, I don't put on a lot of water; after the initial watering in I only irrigate 3X/week for about 10 minutes each time. I think that I don't put on enough water to keep the media very wet. The plants look fine. Most nurseries water daily and some ever add handwatering. Could it be that if nurseries cut back on their irrigation that they could still get good plant growth and reduce their weeds?
In some work I did about 10 years ago, I found that containers irrigated based on soil moisture had considerably less weed pressure than plants irrigated using timer controllers and used less water with no loss of plant quality.
Last week I set out a rain gauge with a data logger to monitor the amount of water applied. After I get a good handle on that I think I will do a quick trial to test my theory whether it's the potting mix or if it's the water amount. Either way, if there's something that will reduce weed pressure, we need to find out what it is.
Jul 22, 2009