Growing native flowers in a salad box

I love lupines and I wanted to grow some for my yard, but also for some school gardens that I volunteer at.  I had read that growing them in a take out food container was a good way to let them grow up enough to more likely survive and stop animals from eating them while tiny.  I started in a regular take out food container, but it was small and they outgrew it quickly.  Then I moved them to these large plastic salad boxes that we get from eating so many green salads.  I drilled 3 holes in one side of each box, so I could use the second container as a flip up top. I wove a string through and tied it. The plants are protected but they can grow up to be pretty big before I plant them out.  Of course I stabbed a slit in the bottom for drainage and in the top so a bit of rain can come in.  They maintain moderate moisture this way.   I have been planting some out and so far about half have survived.  I'll keep gradually planting more out to see if they'll make it.  It seems so much cheaper than buying a full plant.

John S
PDX OR