Treated seeds

We've decided that once we pull an early crop (e.g., spinach, arugula) out of the ground, we should replant with peas while it's still early in the season. That way we supply some nitrogen to the soil (since peas are legumes) and get a vegetable to harvest in the fall. Much to my dismay, I opened up my 5-lb bag of shelling peas to find I had accidentally ordered treated peas. (The seed company we were dealing with was great and agreed to take back the bag and credit my account.)  

The red peas (L) are treated.

Treated seeds are treated with a fungicidal powder (typically Thiram or Captan) as a preventative against damping off diseases and seeds rotting in cold damp soil. The chemicals used to treat seeds can be harmful to human health, and although they are designed to have short half-lives and cling to soil particles so they erode and pollute less, they are also harmful to the environment. Many corn, bean, peas, lettuce and melon seeds, among others, are available treated. 

Treated seeds were developed primarily so large scale growers could benefit from an early yield: treated seeds planted in cold damp soil in early spring are less likely to rot. This increases the germination rate and future yield. But if profit's not your motive, you can just wait until the time is right, when the soil's warmed appropriately for whatever seed variety you are putting into the ground, and you don't have to worry about rotting seeds. With increasing population, high-demand global markets and rising food prices, how could we ever wean ourselves from big ag's use of treated seeds?

As a small-scale grower or home gardener, we have the choice to buy treated, untreated conventional or organic seeds. When you buy seeds online you can be sure to check the box that says "will NOT accept treated seeds" if you plan on growing organically and you will never be shipped a treated product. But another way to avoid treated seeds is to save your own and maybe eve join a seed saver exchange. That way you and your fellow exchange members control both the seed and the growing conditions, ensuring a safer, more locally-appropriate crop.