just my 2 cents:

1. They would be equally effective. Given that I have never found interplanting effective for pests I spose I should say equally ineffective so you might just want to discount this answer ;-)

2. Not really. If you move the containers out of the garden area you might see fewer pests as they will have a wider area to cover, but beyond that I have not found container growing to offer pest/disease advantages over in ground growing with the exception of avoiding soil born diseases.

Hi justaguy2, you may be right about companion planting and pest control. I couldn't find much info other than anectoctal of which there is tons. A study at Virginia Tech on Marigolds and Squash said marigolds with squash had no effect other than marigolds providing a haven for spiders who helped. But a paper by ATTRA (link below) says that the African marigold releases thiopeneÂa nematode repellentÂmaking it a good companion for a number of garden crops.

The link below has good info on companion planting and beneficial plants. I know that when imported cabbage loopers attacked in force my various potted pac choi's etc, they left my raised bed cabbages alone because they went after my radishes instead giving me time needed (trap cropping). But I know, it depends on tons of variables whether a particular companion planting will have any effect.

I think you're right on #2. Other than being able to move containers out of harm's way, I guess there's not much advantage. I suppose the right person could answer that there are disadvantages!

~tom

Here is a link that might be useful: companion planting: basic concepts and resources

The use of certain kinds of marigolds to control some species of nematodes is much misunderstood. The flowers aren't used as a companion crop, but as part of a crop rotation system. Entire sections of a garden need to be planted entirely (solidly) in marigolds, which are allowed to grow and develop normally. The FOLLOWING season, the nematode population will be much decreased, though temporarily.

Marigolds and nasturtiums make great TRAP plants, real magnets for spider mites, for example. I'd never plant them in containers hoping to repel specific critters.

Keeping your container-grown plants free from disease problems is largely dependant upon the quality of your potting mix, your watering practices, appropriate fertilization, and other factors. Trust me....your container grown veggies can end up with all kinds of fungal and bacterial disorders, too. ;-(

Visit a decent hardware store and purchase some copper screen. If you use that in the bottom of your containers, you'll never have any slugs. You can also secure a two or three inch strip of copper or copper screen around the outside of your pots to repel slugs and snails. The mucous from the snail creates a bit of an electrical charge when it touches copper; it doesn't kill the darned things, but they suuuure do hate it! ;-)

lol that's great pratical advice on slugs! thanks,
~tom