Gardeners: Would using roofing tar to coat the inside of a garden box be

[BlackberryMac]

safe when growing vegetables? To give more support and protection to the wood of a garden box my friend suggested coating it with roofing tar. It is already done, but now I am a little afraid of growing veggies in it. Another friend of mine says with all the soil to filter it probably would be fine. The tar is hardened so will it even be a problem?

Will chemicals seep into the soil and then contaminate my veggies? Someone on another site made the point that they use the water that runs from their tarred roof into a water barrel on their garden. Would that contaminate?

If so, what solutions could be possible now that it is done (aside from not growing the veggies and only flowers). Would a liner of some sort work?

In need of answers before I start to plant anything, please.

 

[walt]

Tar never really dries out and will leach into the wood and soil. I would suggest a heavy plastic liner on the sides and gravel in the bottom, not keen on tasting tar in any of my veggies. And your friends rain water is only on the roof for short periods. Moisture and soil would be in constant contact with it in the box.

 

[GeeWally]

We have no idea what chemicals are in that tar. There may be some nasty ones. Next time line the box by stapling thick plastic to it. You'll need to punch two or three holes in the bottom.

Fill the bottom fourth of the box with styrofoam packing peanuts as the roots love the air plus it make the box lighter. Then fill with dirt to the bottom of you plant depth. Next put your plant in and arrange how you like them to be. Then fill dirt around the plant to the top of its roots. Enjoy!