: I know this is off the main topic but i hope someone out there may
: know the answere to this question. I made a fiberglass tomatoe
: planter using polyester resin and matt glass and wondering if it
: could possibly be toxic to grow some tomatoes in it. I am not
: sure but hope that once it is cured all the way it would not be
: toxic. The planter is a large tomatoe and I plan to grow
: tomatoes in it just for the fun of it. I am an organic gardener
: as well as a kayak builder. Any thoughts on the subject would be
: appreciated. Joe

Most cured resins are not only non toxic, but once they are washed a couple times they can be certified food safe by various governmental agencies. There are fiberglass tanks used for storing water on larger boats, for example.

Harder plastics, and this would include some formulations of epoxy resins do have traces of phenols. BisPhenol-A has been in the news recently because it is in the formulation of the plastics (formerly) used for some baby bottles, and those lexan plastic water bottles favored by campers and hikers. As i understand it, this compound mimics, or can stimulate, the action of the female hormone estrogen, which naturally occurs in very small quantities in men as well as in women. Last I heard there was little evidence that any significant amount of this could leak out of the plastic unless the plastic was heated. There was even less evidence to show that any of it which might leak out of the plastic was absorbed in anyone's body. As a precaution (probably a conference call by a bunch of lawyers) the baby bottle industry and many other companies which package their foods in plastic have been relabeling the products to state they are bisPhenol free. Or they are reformulating the plastics they use. I haven't heard of any recall, and read a while ago that the government didn't think it was a hazard, so they weren't interested in recalls. Lots of people who are super vigilant, however, see this as a problem, so the debate goes on. You can certainly google it. If you are an organic gardener you can compare this to the debates between those who use compost and those who use chemical fertilizers.

If you can find the address of the maker of your resin you can write them a letter and ask them about the MSDS (Material Safety Document Sheet) relating to the ingredients in their mix. The hardener for polyester resin is nasty stuff. BUT, once it has reacted with the resin it becomes benign. I suppose an analogous reaction would be to look at grits, or bagels (depends on whether you are from the North or the South) Grits are made by soaking corn kernels in a bath of lye. Bagels get their nice crust by soaking them in (guess what): lye, before baking. Now lye is a nasty alkaline compound and you don't want to eat a spoonful of it. But it is used safely in foods all the time. Frankly, I like both grits and bagels and I don't think the lye used in them has ever hurt me. We eat a lot of strange things and our bodies seem to accept them, process out what we need, and eliminate the waste. For that matter, I wouldn't eat compost or fertilizer, but I have no problem spreading them around my plants.

As for tomatos. As I recall they are members of the deadly nightshade family. Probably more potential toxins in them already than they would ever pick up from anything that might leach out of cured polyester resin. If you are really worried, though, you can line your planters with a plastic bag before filling them with your growing medium. Or you can paint the inside with a natural latex, a synthetic urethane, or some other covering. Like the bartender says: "pick your poison".

good luck with your gardening. I'd give the planter a couple of good rinses with hot water and a rough scrub brush, and then use it happily.

PGJ