I was wondering what kind of containers are safe for growing vegetables. I heard about some numbers for plastic containers.
Are those number labeled on the container? I can’t find any numbers on my containers?
Are ceramic containers safe?
Also how do I know whether the containers are wide or big enough for growing different veggies?
Thank you in advance for your help.
Thank-you for contacting Toronto Master Gardeners with your question about vegetable gardening in containers.
Older or re-purposed containers can be attractive but make sure you are aware of the materials used and any paints or surface treatments that could leach into the container soil. The same caution holds true for glazed terracotta. Unglazed terracotta is generally safe but is not always the best pot to used for container-growing of vegetables because of inadequate drainage (there is usually just the one drainage hole in the bottom). Plastics can be good, especially light coloured ones that do not absorb the heat too much, but, as you note, it is best to use food-grade plastics and avoid using plastic containers with recycling numbers of 1, 3, 6 or 7. These numbers are found on the bottom of the pot in the triangle shape.
The following link is to a good listing of the plastic codes and their meanings:
The size of the pot is an important consideration for growing vegetables as well. Here are some guidelines for pot sizes for various vegetables:
Good luck with your container vegetable garden!