Wednesday, November 28, 2007

The Dream of Sweet Corn.

You put a big pot of water on the stove and walk into the field. The sweat drips off your face and a light breeze cools you. You pick a dozen or two ears, husk them, and throw them right into the water.

That is the taste of summer.

Yet, sweet corn production has long eluded us. To the point we have not tried to grow it for our CSA. You may rightfully ask, "Why?" As you drive down rural roads or into our valley you see lots of sweet corn, so how hard can it be?

If you are going to use conventional practices it is not that hard. Just fertilize it, douse the area with herbicides, and apply lots of pesticides and you are done. But for an organic producer or for someone like us, not organic but strictly sustainable, it is not so easy.

To start with corn is a heavy feeder. It LOVES its nitrogen. This coming year that should not be that big an issue, but in the future the recommended rotation for sweet corn is to precede it with 2 years of clover or legume cover crops. Then it needs lots of phosphorous which is an issue. Fertilization can be sustainably achieved with foliage feeding (spraying the leaves) to reduce the cost of fertilizers, but they are still pretty expensive.

Then come the weeds. You can plant corn under plastic mulch, but that makes planting harder. You can also use straw mulch, but that is pretty labor intensive (without a spreader which we do not have.) The options are to hand weed (hoe) or flame baby weeds. Both are options but time is always a huge issue for us (remember we work full time jobs in addition to the farm.)

And once you get past all that you are faced with the biggest issue of them all. BUGS! Corn worms are a huge problem. There are some varieties of sweet corn which are more resistant to Corn Earworms, but not being open pollinated we would prefer to avoid them. So what is a grower to do? To not do something is to loose 80%-95% of your crop, obviously not acceptable.
So you take vegetable oil and mix it with Bt (well-known microbial pesticide commonly used to control lepidopterous pests). But aerial application of it does little good. So instead... "direct application of Bt mixed with vegetable oil to individual corn ears, applied two to three days after silks have extended to their maximum length (full brush.)"

Time it wrong and you are done. And ideally you will repeat the treatment 2 or 3 times. So you have to individually treat the silks of each ear of corn multiple times, and then you should loose only about 20% of your ears... Other pests love sweet corn to, but theBt takes care of some of them and other methods like strong rotation or foliar spraying of Bt can control those pretty well.

In 2008 we plan on doing a small trail of sweet corn. It will be expensive, and I'm not sure most will realize the difficulty in us growing what others seem to so easily, but we want to try. I would be surprised if members got much more then a dozen ears during the season, but it will be a start.

Just remember next summer, when you buy your sweet corn, to ask that grower the same questions you would other farmers. Sustainable sweet corn is possible, but difficult.

1 comment:

Anonymous said...

I am looking forward to even a dozen ears of yummy corn! Summer Dreaming...