Production Notes and Flaming Pigweed

The lovely little oakleaf lettuces in your boxes this week are two varieties that are new to us this year. We are so pleased with them that we will probably put them in our regular lettuce rotation. Let us know what you think.

This week’s fava beans (part of the mystery) are all from our Redman House field. It has been a while since I last grew favas, and I made the mistake of planting them too close together in the rows. The plants grew beautifully (a little too beautifully) but because they were spaced so closely together, the patch became a jungle-like thicket that is a real challenge to harvest. The beans are excellent, however, and because we are picking them on the early side, the skins are still tender. (So don’t worry too much about removing the skins for cooking!)

For some the mystery will be our first pick of summer squash. We had expected to start picking this block several weeks ago but the storms at the end of March, and cool temperatures in April, slowed things down. We will be picking more and more over the coming weeks and we’ll be sure to rotate packing days so that everyone gets some.

As those who have come to our farm tours have probably heard me say, organic growers are at more of a disadvantage (compared to their conventional counterparts) not in dealing with pests or diseases—but in controlling weeds. Our biggest operating expense on the farm is labor, and weed control is among our highest labor activities. In fields with well-endowed weed “seed-banks” (meaning having lots of viable weed seeds), the expense of hand weeding can make some crops a losing proposition. Conventional growers may use fumigation to kill off viable weed seeds in the soil, or band on pre-emergence herbicides at planting time, or even apply selective post-emergence herbicides after their crops have broken the surface—all options that are obviously not available or desirable to organic growers.

We do have some tricks up our sleeves, however, and amongst these my favorite is the use of a propane flamer to kill weeds. This implement attaches to the back of our tractors and has four burners that pass over the top of our vegetable beds. It can be used in a number of ways. One of my favorites is the “stale-seedbed” technique where we prepare our beds for planting as usual, but before actually planting we soak the field a couple of times and wait ten days to two weeks. This brings up most of the viable weeds that are in a position to germinate. We then pass over the field with the flamer to kill off the weeds that have emerged and then plant the next day into a nice clean field. Another way to use the flamer is to make a pass over the field after planting a crop. This works really well with things that take a long time to germinate like carrots, parsnips, parsley and onions. Because most weed species emerge before these crops do, if our timing is right, we can kill most of these weeds, and the crop will emerge a day or two later with very little competition.

We can even use the flamer with some extra-hardy crops like garlic or corn after the crops have emerged. Although these crops may get a little singed around their edges, they can withstand direct contact with the flames whereas the weed seedlings that surround them mostly perish.

It is in this way that I used the flamer on our potato planting last week. We planted the potatoes this year on the back hill at our home farm. It is one of those “out of sight, out of mind” fields that unfortunately doesn’t always get the attention it needs. As a result, it has a hefty weed-seedbank with a lot of pigweed (an amaranthus species) in it. A week after watering in the newly planted seed potatoes, the whole field had a distinct reddish glow from the millions of newly germinated pigweed seedlings that had emerged. I usually make a flaming pass after planting potatoes no matter what field they are in, but I knew that in this instance it would be particularly important. Timing is critical in a case like this, if you make the flaming pass too early, a large number of weeds that haven’t yet broken the surface will emerge unscathed. If you make the pass too late, you will do serious damage to your crop, and a higher number of weeds will survive because they are large enough to withstand the heat.

This year I think I hit it just right. Although some of the potato varieties had already begun to emerge, they were at an early enough stage so that the flame did them little harm. And most of the weed seeds that were in a position to germinate had already emerged. As the rest of the potato varieties emerge and the field begins to fill out, it is particularly gratifying to look out on a clean crop—with few weeds to compete with it. This is the farmer’s version of having a clean house!

Here is a picture of a potato plant that survived a quick pass with the flamer. The weeds around it are dead, but the potato will be fine. This year we planted nearly six tons of seed potatoes (a lot for us!) of six different varieties. We should start digging the earliest varieties as “new” potatoes as early as June.