One of the most difficult aspects of growing without chemicals is weed management. No chemicals means no herbicides. Many people think that means lots of time is going to be spent hoeing weeds. I hate that. Hoeing weed can really eat up the time of our employees and I often wonder if we really can make enough money selling kale to pay to have these guys out there weeding. I have several strategies to keep everyone out of the hoeing business. The most important is to have a zero tolerance for mature weeds. Once a weed blooms it is able to develop seeds that populate the soil and can cause problems for years. If weeds are closely managed and no seeds repopulate the soils, eventually the fields will get cleaner and cleaner due to simple reduction in viable seeds in the soil.
Not only do we try to never let a weed bloom and make seeds, we also plant our crops very close together in order to shade out any new weed seedlings. This means that in the few weeks just after the crop emerges, we might need to quickly hand hoe any weeds that emerge. But, within a short time the crop should grow up to the point that it shades out any area that weeds might germinate in. The weeds really can’t grow in the dark area under the crop.
In addition, it helps to cover any open areas in straw. This not only smothers any weeds that might germinate in the walk ways, it also continually adds organic matter to the field. We used to try to straw all under the crop but discovered that the straw was constantly in the way when we harvested. So now straw only goes in the walkways and under trellised crops. We took this idea of smothering potential weeds to a new level this year. When we pulled out our winter crops, we simply laid them down on the ground in the row by the newly planted crop. The idea is that this plant debris will eventually break down and help build the soil. It also saves time and labor by not having to haul the old plants to the compost pile and then haul the finished compost back to the field. I remember when I was in graduate school studying plant diseases I was taught that the key to preventing diseases is to keep the field extremely “clean” with no plant debris or old plants around. It was pretty hard for me to break this rule and just lay down old plants to rot between the rows. To be honest, I really haven’t seen any increase in plant diseases using this method. That is a little against the traditional plant pathology wisdom, but it works for me. If this beautiful dance is timed correctly, very little hand weeding has to happen. I know our farm helpers thank us for this.