We inadvertently demonstrated the effect of pressure treated boards on garlic. Last year Jed made three raised beds for me to play with so that the birds wouldn't get into them. Last season we cleared out the duck pond and moved all that "mud" into the two small raised beds (by small I mean 3x12ft) and then layered them with topsoil. These two beds we used to plant our garlic. This year we tried out a variety called Spanish Roja that the local farm supply stocked. Approximately 70 cloves went in to each bed in October. All were planted about an inch down into the soil and covered with about 3 inches of straw. Both were watered at the same time, weeded at the same time, and mulched at the same time. The only difference was that one bed was made using old boards, and the other was made using old pressure treated boards. I wish I could have taken a picture when the greens were growing to show the difference.
It was immediately obvious that the pressure treated bed was not doing well. Of the 70 cloves that we planted in each bed, all of them grew in the plain board bed while only 11 grew in the pressure treated bed. We planted another 70 cloves into the pressure treated bed hoping it was just a bad batch we put in there. Once again, most did not sprout and in total we had only 22 garlic grow.
Around the time that they were mature we placed the baby chicks in with the failed garlic bed and they, of course, ate and trampled all the greens. Not much of a loss as the garlic had technically finished growing.
As the last of the greens in the good bed finished falling over I decided to harvest the garlic this weekend and since I was unable to take a picture of the greens to compare them I thought I'd show you a picture of the harvest for you to see the results. The first image is of the sad garlic in the failed bed when I first put the chicks into the bed. The second image shows the big braid of garlic from the good bed followed by a picture of the small heads of garlic from the good bed, and I did not picture the smaller heads that I put straight into our garlic drawer. The last picture is the entirety of the harvest from the pressure treated bed. (Ivan is helping)The lesson learned from this experiment was that no matter how old the pressure treated board is that you are trying to use in your garden, it seems as though it will continue to leach out chemicals while it is in use. I know many people say that it is safe to use pressure treated boards as edging for your garden and that it won't affect your plants, but the garlic seem to tell us a different tale. I don't know whether to try planting legumes in the same beds to see if this effect is true for more than just one crop or to skip the trial as I'm playing with things that I and my family will consume. Knowledge is power, but formaldehyde is not something I want my food to play with when my family is involved.
And also, for companion planting - garlic and peas do not grow well together. The growth of the garlic is stunted. I did not notice a decrease in productivity in the peas.
