Skeptic here, too, for the most part. I *have* found nasturtiums to work very well, though. You have to remember, however, that they're a trap crop, not a repellent. Nasturtiums are more attractive to some pests than the crop you're trying to protect, so they go to the nasturtiums first. You can then kill the pest on the nasturtiums (either by organic or synthetic pesticide or by simply removing the nasturtiums along with the resident pests). Whatever method you choose, you're sacrificing the nasturtiums on purpose to save the crop. In our in-ground garden, I plant a row of nasturtiums next to the row of crop I want to protect. With pots, I'd definitely have the nasturtiums in their own separate pots. As far as repelling pests, I still haven't found any plant that lives up to the companion planting hype. The problem is, the majority of them only work when they're jostled or crushed to release the offensive (to the pest) scent. That just doesn't happen enough in the average garden unless the plants are right on the path getting stepped on and brushed against. I just don't have the time and space for that. The dill and brassicas combo is the one other CP that has worked well for me. I have no idea why. It's just been a consistent observation that the years I plant a row of dill in between my rows of broccoli, I have healthier plants and bigger harvests. *shrug* That's not to say that that would happen for everyone, though. Another lucky gardener here who doesn't have to deal with slugs. We have them, but not many. They stay way out by the slough (pond) with the snails and the only place I've ever seen them in the garden is under the rhubarb when I haven't had time to keep it tidy and off the ground. My dad used to have them, though. Horrible things. He used to send me out with a salt shaker when I was a kid. *shudder*

I got those blue and pink ones, they do a great job with primulas to put color into the landscape. Mine have finished blooming and I broke off all their spent flower stalks to let them look neat again. I got a lot of Japanese primulas now, they are self-seeding reliably, there is one in my picture of h.'Dick Ward' in a recent posting. Bernd

I grow marigolds on the edges of my lasagna beds, but it's more of a pretty factor than a companion factor. And with this years bed rotation, the marigolds are on the edges of pepper, squash, and bean beds, and not along the tomato beds at all, lol. And I thickly direct sow marigold seed too- that way it's a nice bushy border and if/when they get bug-tacular I can just pull those plants if needed. This year it's carrots and leafy greens edging the tomato beds- but that's more of a got that little space left over I can cram them into rather than companionship. But hey, if it helps, why not? I've never been sure how basil is supposed to improve tomatoes either- I always figured it was kind of an old wives tale because tomatoes and basil are so often companioned in cooking rather than the growing aspect of it. I would never grow garlic in my tomato bed- my garlic gets it's own beds, and honestly is one of the only beds that is perfectly picked clean of anything that could compete with the garlic. Garlic might be good for tomatoes, but I wouldn't want to chance tomatoes out competing my garlic. Borage gets it's own growing space too, because it has it's own application, and I don't want it competed with. I grow calendula aside too for the same reason. My sage is in the herb garden, and I don't grow chives because I have large swaths of my lawn that are thick with wild chives so I don't need to grow any. Nasturtiums can be a great companion plant as far as I'm concerned- but as a companion plant only as a trap plant that I'm willing to sacrifice. I had a nasty aphid infestation last year, and the nasts trapped almost all of them- and when a bit of the plant got infested, I promptly cut it off and drowned it. I grew them next to peppers and squash last year, and they didn't get a single aphid. I wouldn't rely on nasts as a companion to just let sit and do whatever. But then I have the tendency to grow hedgerows of nasts because I use them a lot for various eating too, so I can use them as sacrificial companions and eating plants.

@sepulvd since we don't know the balance of your current planting design you can always follow your own thought, "maybe add different colors of heather". It would certainly be a safe solution since most of the textures will blend. Monocultures of one genus can be captivating.