Since we use only organic fertilizers and don't use any pesticides, not even ones that could be used under the organic label, I am often asked why I don't go through the paperwork required to obtain the certified organic label.
To be certified I would need to track our sources of seeds, transplants and seed potatoes back a generation to ensure that the previous generation of plants had been grown using organic methods. This presents a challenge to us for 2 reasons. First is the high cost of certified organic seeds and especially organic seed potatoes which would require us to charge more for our produce. We use only untreated seed, but they aren't necessarily certified organic. The other challenge is that we don't have our own greenhouse for starting tomatoes, peppers, broccoli etc, so we rely on a commercial greenhouse that isn't certified organic to start our transplants.
So our promise is that from the time the seeds and transplants are in our soil, they are grown without pesticides. Many of our customers feel this approach is preferable anyway, because they don't have to worry about residue from even "organic" pesticides on the produce they buy from our farm.
In order to grow the produce on our farm without any kind of pesticides we rely on a variety of techniques that focus on soil and plant health rather than trying to completely eliminate pests. Here are some of the sustainable techniques we incorporate.
We rely heavily on cover crops to maintain the organic matter, texture and nutrients of the soil. Our field is very long and narrow, so we can easily rotate our crops. I've found potato beetles in particular aren't very mobile and are controlled by planting the potatoes far from where they were the year before. This doesn't completely eliminate the beetles, but the ones that show up can be easily picked off.
For cabbage worms and flea beetles, we use floating row covers on our broccoli, cauliflower and cabbage which lets in the light, air and moisture without permitting the insects to get to the plants.
Our tomatoes eventually get blight in the field, so we plant repeatedly to help ensure that there is a steady supply of healthy plants coming into production rather than trying to keep the old plants producing once they get blight. We also had good success last year with tomatoes in our hoophouses where we water them with drip tape. Since their leaves didn't get wet, they didn't get blight and they produced well from late June into October.
We also use varieties of vegetables that we've found do well in our soil and conditions and seem to grow with less trouble from pests, downy mildew or adverse weather conditions. I no longer grow sweetcorn, because I was disappointed with the quality of the corn without any pesticide use. (The sweetcorn for our CSA subscriptions and farm stand are from Evan Showalter's farm.)
Some of our crops have less pest trouble certain times of the year. For example turnips for us get hammered by flea beetles in the spring but don't seem bothered by them in the fall. And fall carrots aren't susceptible to carrot rust fly like the midsummer plantings, plus they are much sweeter.
With eggplants, which seem to be the favorite of many insects, I've noticed that we have an advantage over home gardens that only have a couple of plants. We plant a long row of hundreds of plants. Every year the couple of plants on the very ends get hammered by pests, but seem to shield all the rest of the plants in the middle from attack. It's as if any pests in the neighborhood looking for eggplants settle in to eating the "sacrificial" end plants and don't want to go any furthur, which protects all the others.
With over 25 types of crops (over 50 varieties) that all have their own specific soil needs, pest pressures, and ideal weather progression, there is always more to learn.