I always pot-up small plants into 1 gal containers to get bigger and make a better root-mass before planting out. Small guys just won't survive our CA summers. I can't imagine that doing the same for yours won't be a benefit as well.

I winter sow lavender and pot the tiny little seedlings in 3" pots, then repot into 1 gal pots before overwintering them successfully. I overwinter my potted perennials by digging a hole in my vegetable gardens (in Oct for zone 6 after the veggie garden has been put to rest) and placing the pots into the holes (pots at soil level) and surrounding the pots with soil. I also allow leaves to accumulate on top but only about an inch or so. This way they are watered by the rain and snow and I don't have to worry about them drying out in my basement or a greenhouse (if I had one). I've never lost anything this way, infact last year I ran out of pots and planted the tree seedlings directly into the garden until I could plant them in the spring.

This year I am also directly transplanting the tiny seedlings into my gardens because I know where I want to put them.

If the plugs you received are that small I would assume the lavender you received is from seed not cuttings (which would have given you a truer lavender).

Grosso does not propagate with seeds, so they are plugs from cuttings. Most likely the hidcote is from cuttings also.

Having said that I have no advice other than to make sure that your potted lavenders are not sitting in drip trays, as they hate "wet feet." I don't do container gardening, all of my lavenders are planted outdoors in the ground.

If you know where you want them placed there's no reason not to plant them outdoors. I'd rig a shade cloth for their first few days, but I'd give it a try with some of them. 150 potted plants are a lot to deal with. You're going to need careful watering no matter whether they are in pots or in the ground.

Keep in mind that I am biased though...I kill plants in pots. I'm very good with growing things in the ground.

:-)