Lavender is a full sun plant - 6 or more (preferably more) hours of direct sun. It likes a lean, well drained soil and only requires sufficient water to become established and after then, only when weather or soil becomes very dry. No fertilizer. Lavender will be marginally hardy in your climate, so select from the hardiest English lavender cultivars, Lavandula angustifolia, which tend to have the greatest cold tolerance.

I second all the above advice

we re-did/ edit a perennialplanting last fall, including Lav angustifolia in groups. The ones in the middle of a group hardly had any roots you could just pull them out by hand.

So plant them well spaced, they seem unhappy when getting crowded

I have traditionally not grown lavender, because of how poorly it does in our climate. I saw Lavender x 'Phenomenal' being touted all over the place as a super easy to grow lavender with none of the pitfalls of the species plants. "Yeah right," I thought. So what did I do? Bought half a dozen plants, planted them on the North-West corner of my house(3-4 hr sun a day), under a downspout. "This will be the real test." I expected these plants would be dead by the end of the Spring rains. 10 months and one Winter later, they are FLOURISHING. They had two >6" snowfalls this Winter that each melted in <2 days. I'm in awe. Rarely does a plant make me this giddy, but 'Phenomenal' seems to be a keeper for wet/Northern/part Sun gardens. Give it a try.